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Tektronix WFM91 Stereo System User Manual

1. Short pad Long pad 4 Standoff post inserts gt into LCD display case LCD locator feet 4 9 7 Figure 6 3 Installing the LCD display LCD Display Padding To remove the LCD display padding perform the following procedure 1 Remove the top cover Refer to Top Cover on page 6 7 2 Remove the LCD display module Refer to LCD Display on page 6 9 WFM 90 and WFM 91 Service Manual 6 11 Removal and Replacement 6 12 3 4 Remove the display padding from the side of the LCD display module Clean any remaining glue residue from the side of the LCD display module Refer to Cleaning on page 6 3 To replace the LCD display padding perform the following procedure 1 2 3 4 Peel the protective cover from the LCD display padding Align the padding with the top surface of the LCD display module and press the padding onto the side of the display See Figure 6 3 Install the LCD display module Refer to LCD Display on page 6 9 Install the top cover Refer to Top Cover on page 6 7 Backlight To remove the backlight from the LCD display module perform the following procedure 1 2 3 5 Remove the top cover Refer to Top Cover on page 6 7 Remove the LCD display module Refer to LCD Display on page 6 9 Remove the display padding from the side of the LCD display module where the backlight is installed Remove the two outside reta
2. xiv WFM 90 and WFM 91 Service Manual Introduction Service Strategy Service Offerings Warranty Repair Service NOTE Throughout this manual any field replaceable component assembly or part of this oscilloscope is referred to generically as a module This manual contains all the information needed for periodic maintenance of the WFM90 or WFM91 Handheld Waveform Vector Picture and Audio Monitor Examples of such information are procedures for checking performance and for readjustment Further it contains all information for corrective maintenance down to the module level The procedures diagrams and other troubleshooting aids help isolate failures to a specific module rather than to components of that module Once a failure is isolated replace the module with a unit obtained from Tektronix Inc All modules are listed in Mechanical Parts List To isolate a failure to a module use the troubleshooting procedures located in Maintenance remove and replace any failed module follow the removal and replacement instructions located in Maintenance Tektronix provides service to cover repair under warranty as well as other services that may provide a cost effective answer to your service needs Whether providing warranty repair service or any of the other services listed below Tektronix service technicians trained on Tektronix products are best equipped to service your instrument Tektronix technicians are apprise
3. 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 Adjust the peak to peak detector Plus amplifier and input control fully counterclockwise Adjust the sine wave generator for a display amplitude of 100 IRE 700 mV PAL Note the digital multimeter readout level or the oscilloscope dc level Set the sine wave generator frequency to 3 58 MHz 4 43 MHz PAL Adjust the sine wave generator amplitude for exactly 100 IRE 700 mV PAL of display Check that the digital multimeter readout level or the oscilloscope dc level is within 7 mV of the reading noted in step 19 Set the sine wave generator frequency to 6 MHz Adjust the sine wave generator amplitude for exactly 100 IRE 700 mV PAL of display Check that the digital multimeter readout level or the oscilloscope dc level is within 7 mV of the reading noted in step 19 Select X1 GAIN from the Operating menu Remove the dual input coupler from the instrument Connect the function generator output to the VIDEO IN connector using a X10 75 2 attenuator Select 1H SWEEP from the Operating menu Enter the Configuration menu and select the INPUT category Select EXT REF and SLOW DC REST Set the function generator to output a 60 Hz 50 Hz PAL sine wave with a display amplitude of 100 IRE 700 mV PAL on the WFM 90 or 91 Handheld Waveform Vector Picture and Audio Monitor Connect a black bur
4. 5 2 Table 6 1 Tools required for module removal 6 5 Table 6 2 Removal and replacement procedurelist 6 6 Table 6 3 Equipment required for troubleshooting 6 31 Table 6 4 Low voltage power supplies 6 35 Table 6 5 Fault symptom table 6 36 Table 8 1 Replaceable parts list column descriptions 8 2 WFM 90 and WFM 91 Service Manual Table of Contents vi WFM 90 and WFM 91 Service Manual I Ii General Safety Summary Review the following safety precautions to avoid injury and prevent damage to this product or any products connected to it Only qualified personnel should perform service procedures To avoid potential hazards use this product only as specified To Avoid Fire or Shock Hazards Use Proper Power Source Do not operate this product from a power source that applies more than the voltage specified Use Proper AC Adapter Use only the specified ac adapter provided with this product to connect it to the mains supply Avoid Electric Overload To avoid electric shock or fire hazard do not apply a voltage to a terminal that is outside the range specified for that terminal Do Not Operate Without Covers To avoid electric shock or fire hazard do not operate this product with covers or panels removed Use Proper Fuse To avoid fire hazard use only the fuse type and ra
5. Troubleshooting Procedures Connector Diagram Figure 6 32 illustrates the connector and pin locations of the circuit board connectors listed in the troubleshooting flowcharts 246810 246810 Fuses Ju J 16 as seen from the Bottom A back of the Bottom board board 20 3 5 113579 11 13 15 17 19 9 Jio 2 46 8 10 12 14 16 18 20 J16 5 Ground test point beat 9 as seen from the front of the Top board View of the Top and Bottom boards 57 53 49 45 41 37 33 29 25 21 17 13 9 5 1 as seen from the 59 55 51 47 43 39 35 31 27 23 19 15 11 7 3 keypad side 58 54 50 46 42 38 34 30 26 22 18 14 1062 60 56 52 48 44 40 36 32 28 24 20 16 12 8 4 T J9 13248V J9 14 8V Sa 19 19 15 45V Figure 6 32 Circuit board connector and pin locations 6 50 WFM 90 and WFM 91 Service Manual Options D Options and Accessories This section lists the instrument options and accessories that can be ordered for the WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor Refer to Parts Ordering Information on page 8 1 for information on how to order parts for this instrument Refer to Replaceable Parts List on page 8 5 for the Tektronix Inc part numbers to use when ordering replacement parts Options The options listed below can be ordered with the WFM 9
6. 202 0338 20 378 0418 00 348 1436 00 348 1437 00 174 3287 00 ADC 016 211 0294 00 SJ 100 348 1442 00 MB 100 UC04 H R473 002 T1R ORDER BY DESCRIPTION ORDER BY DESCRIPTION ORDER BY DESCRIPTION 1224 02 00 0541 333 4144 00 671 3044 00 174 3288 00 671 3045 00 671 3045 01 671 3045 02 671 3045 03 671 3045 00 671 3045 01 671 3045 02 8 5 Replaceable Parts List Replaceable Parts List Cont Fig amp Index Tektronix Serial No Serial No Number Part Number Effective Discontd Qty Name amp Description Mfr Code Mfr Part Number 671 3045 03 8030000 1 CIRCUIT BD ASSY BACKLIGHT WFM91 80009 671 3045 03 20 337 4000 00 1 SHEILD BACKLIGHT ECB 0 005 POLY MIDE 80009 337 4000 00 21 211 0878 00 6 SCREW 4 40 X 0 5 LONG PAN HD SCREW TORX 0KB01 211 0878 00 DRIVE BLACK ZINC PLATED W LOCKING PATCH 22 214 4636 00 1 RCPT TURNLOCK F RECEPTACLE USED WITH 94222 82 35 309 56 SOUTHCO SNAP IN STUD 23 200 4201 00 1 BATTERY DOOR MTC POLYCARONATE 80009 200 4201 00 24 358 0792 00 1 BUSHING RETAINR STUD RETAINER SOUTHCO 94222 82 32 401 41 25 355 0286 00 1 STUD TURNLOCK OVAL HEAD STL SOUTHCO 94222 82 11 520 16 26 346 0279 00 1 STRAP CARRYING 1 00 X 11 00 CARRY HANDLE 80009 346 0279 00 27 348 1428 00 1 PAD CUSHIONING MTL 0 062 THICK PORON 80009 348 1428 00 28 210 0589 00 2 NUT SLFLKG HEX 4 40 X 0 246 STL CD PL 39951 ORDER BY DESCRIPTION 29 334 8830 00 1 MARKER IDENT BATTERY 0
7. Check for a display amplitude of 140 IRE 5 IRE 1000 mV 50 mV PAL 12 Select X1 GAIN from the Operating menu Variable Gain Range and This procedure verifies the following requirement Vertical Position Range Variable Gain Range Input signals between 0 8 V and 2 V can be adjusted to 140 IRE 1 0 V display 160 mV and 400 mV for X5 Gain Vertical Position Range 1 V signal can be positioned so that peak white and sync tip can be placed at blanking level with the DC Restorer Clamp on regardless of gain setting 1 Set the VAC for a 999 9 mV output 2 Select VAR GAIN ON from the Configuration menu 3 Check by adjusting the Variable Gain controls that the signal amplitude can be displayed less than 70 IRE 500 mV PAL WFM 90 and WFM 91 Service Manual 4 7 Performance Verification 4 Setthe VAC for a 799 9 mV output mn Check by adjusting the Variable Gain controls that the signal amplitude can be displayed greater than 140 IRE 1000 mV PAL Select X5 GAIN from the Operating menu Set the VAC for a 399 9 mV output Enter the Configuration menu and select the VAR GAIN category Check by adjusting the Variable Gain controls that the signal amplitude can be displayed less than 140 IRE 1000 mV PAL 10 Set the VAC for a 159 9 mV output 11 Check by adjusting the Variable Gain controls that the signal amplitude can be displayed greater than 140 IRE 1000 mV PAL 12 Replace the VAC si
8. press it onto the bottom cover See Figure 6 13 3 Rub your fingers over the battery cushion pad once it is positioned on the bottom cover to make sure the pad is securely in place Line up holes to aid positioning Battery orientation Figure 6 13 Battery orientation marker position 6 28 WFM 90 WFM 91 Service Manual Removal Replacement 4 Peeloff the protective covering of the adhesive surface of the battery orientation marker 5 Position the battery orientation marker in place above the battery cushion pad before you press it onto the battery cushion pad See Figure 6 13 6 Rub your fingers over the battery orientation marker once it is positioned on the battery cushion pad to make sure the marker is securely in place 7 Install the battery cover Refer to Battery Cover on page 6 18 AC Adapter EMI To remove the AC adapter EMI suppressor perform the following procedure Suppressor se 1 Release the retaining latches on the side of the EMI suppressor 2 Pull the AC adapter cord from the EMI suppressor To replace the AC adapter EMI suppressor perform the following procedure 1 Place the EMI suppressor within 12 inches of the end of the adapter cord NOTE The EMI suppressor is most effective when placed close to the end of the AC adapter cord 2 Loop the AC adapter cord through the middle of the EMI suppressor Close the EMI suppressor until the sides of the suppressor la
9. 0 75 Q minimum loss attenuator Connect one side of the dual input coupler to the VIDEO IN connector Connect the 015 0413 00 Peak to Peak Detector Head to the other end of the dual input coupler using the female to female BNC connector Connect the other end of the Peak to Peak Detector Head to the 015 0408 00 Peak to Peak Detector Input Connect the peak to peak detector Output to the digital multimeter or oscilloscope Set the leveled sine wave generator frequency to 50 KHz and adjust the generator amplitude for exactly 100 IRE 700 mV PAL of display Adjust the peak to peak detector Plus amplifier and input control until the green LED is on Note the digital multimeter readout level or the oscilloscope dc level Set the sine wave generator frequency to 3 58 MHz 4 43 MHz PAL Adjust the sine wave generator amplitude for exactly 100 IRE 700 mV PAL of display Check that the digital multimeter readout level or the oscilloscope dc level is within 14 mV of the reading noted in step 8 Set the sine wave generator frequency to 6 MHz Adjust the sine wave generator amplitude for exactly 100 IRE 700 mV PAL of display Check that the digital multimeter readout level or the oscilloscope dc level is within 14 mV of the reading noted in step 8 Set the sine wave generator frequency to 50 kHz Select X5 GAIN from the Operating menu WFM 90 and WFM 91 Service Manual 4 9 Performance Verification 4 10 17
10. 11 12 13 14 15 16 17 18 19 20 21 Select SWEEP from the Operating menu Select SWEEP from the Calibration menu and then select CAL Adjust the Arrow Buttons for one cycle per major division Select CAL MENU and then select SAVE Set the function generator frequency to 100 KHz Select 2H SWEEP from the Operating menu Select 2H SWEEP from the Calibration menu and then select CAL Adjust the Arrow Buttons for one cycle per major division Select CAL MENU and then select SAVE Replace the signal on the VIDEO IN connector with the output from the leveled sine wave generator Use the 50 2 to 75 2 minimum loss attenuator and precision 196 50 cable if the generator specifies a 50 Q output Set the sine wave generator for a 1 MHz output Select MAG ON from the Operating menu Select MAG GAIN from the Calibration menu and then select CAL Adjust the Arrow Buttons for one cycle per major division Select CAL MENU and then select SAVE Select MAG OFF from the Operating menu Replace the signal on the VIDEO IN connector with a 7596 color bar signal from the television signal generator using a 75 Q in line terminator Select 2F SWEEP from the Operating menu Select 2F SWEEP from the Calibration menu and then select CAL WFM 90 and WFM 91 Service Manual 5 5 Adjustment Procedures Vertical Gain and X5 Gain 5 6 Registration 22 Adjust the Arrow Buttons for a sweep length o
11. 19 Check that the display amplitude is within 0 5 dB of the reference level graticule lines 20 Set the audio generator frequency to 10 kHz 21 Check that the display amplitude is within 0 5 dB of the reference level graticule lines 22 Set the audio generator frequency to 15 kHz 23 Check that the display amplitude is within 0 5 dB of the reference level graticule lines 24 Set the audio generator frequency to 20 kHz 25 Check that the display amplitude is within 0 5 dB of the reference level graticule lines 4 14 WFM 90 and WFM 91 Service Manual 7 Adjustment Procedures Adjustment Procedures This section contains the following information m Summary adjustment procedure m List of equipment required to perform the procedures m Adjustment procedures Summary Adjustment Table 5 1 is the summary adjustment procedure and is intended for those who are familiar with the complete adjustment procedures Adjustment titles and page numbers provide a cross reference to the adjustment procedures on the following pages Table 5 1 Summary adjustment Adjustment Preliminary setup Page 5 4 Raster VCO 5 4 Sweep timing and horizontal mag registration 5 5 Vertical gain and X5 gain registration 5 6 Frequency response 5 1 Vector quadrature phase 5 8 Vector gain and X5 gain phase 5 9 Audio gain WFM 90 and WFM 91 Service Manual Adjustment
12. 250 X 11 000 X 0 125 CA ASSY SP FLAT FLEX FLX 20 26 AWG 0 050 CTR 4 0 LCUT amp STRIP X RTANG PCB STAGGERED OWER DC PCB MALE RTANG 2 0 MM DIA M H X 3 3 MM TAIL 3 COND W SWITCH JACK P PIN 7 MTG POST DC SCREW MACHINE M3 X 0 5 X 10MM PNH STL CDPL T 10 TORX DR CONN W SHU 5 TER INAL W O THD LCD FOOT LCD LOCATOR FOOT MOUNT RESILIENT COMPRESSION MOUNT DIA X 0 320 THK COMPOSITE W 0 2 L 4 40 0 280 THD STUD FUSE WIRE LEAD 2 0A 125V 1 SEC MIN 60 SECTROLLED NUT PL ASSEM WA 4 40 X 0 25 STL CD PL SCREW TPG TF M3 0 5 X 10MM L TORX DRIVE BLACK ENDURION NUT PLAIN HEX 0 5 28 X 0 562 HEX BRS CD PL WASHER LOCK 0 521 ID INT 0 025 THK SST PANEL REAR POLY CARBONATE CIRCUIT BD ASSY INPUT BOARD ASSY SP DISCRETE CPD 2 24 AWG 300V TEFLON 2 3 L 1X2 0 079 2MM 0 079 2MM RC CIRCUIT BD ASSY BACKLIGH CIRCUIT BD ASSY BACKLIGH CIRCUIT BD ASSY BACKLIGH CIRCUIT BD ASSY BACKLIGH CIRCUIT BD ASSY BACKLIGH CIRCUIT BD ASSY BACKLIGH CIRCUIT BD ASSY BACKLIGH X 1X4 TWF TWF TWF ACK PHONE PCB FEMALE RTANG 3 POS NT 3 5MM ID 0 354 X 0 137 TAIL T WF M90 T WF M90 90 T WF M90 91 T WFM91 91 Mfr Code 80009 80009 80009 80009 80009 80009 2427 0 01 OLXM2 80009 1415 15915 0 01 93907 13143 0 01 80009 80009 80009 80009 80009 80009 80009 80009 80009 80009 Mfr Part Number 202 0338 00
13. 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor must have been adjusted at an ambient temperature range of 4 20 to 30 C and must have been operating for a warm up period of at least 20 minutes WFM 90 and WFM 91 Service Manual 5 3 Adjustment Procedures Adjustment Methodology 5 4 Preliminary Setup Raster VCO The following information provides you with an overview of how adjustments are made on the WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor Calibration Menu To enter the Calibration menu press and hold the CONFIG button for a few seconds The Calibration menu display consists of a list of instrument adjustments along with two action selections CAL and SAVE Select CAL to enable the adjustment that is currently selected from the list of adjust ments SAVE must be selected after every adjustment to save the adjustment in memory NOTE SAVE must be selected from the Calibration menu after each adjustment is completed to save the adjustment in memory If an adjustment is not saved the instrument will revert to the original adjustment setting on the next power up After you have enabled an adjustment select CAL MENU to return the display to the main Calibration menu Most adjustments provide a POS or PHASE menu selection which allows you to toggle the Arrow Buttons between the selected adjustment and signal positioning to aid in performing the adjustment Perform t
14. ASSY TOP BOARD WFM90 80009 671 3042 01 671 3042 02 B010503 B010903 1 CIRCUIT BD ASSY TOP BOARD WFM90 80009 671 3042 02 671 3042 03 B010904 B011802 1 CIRCUIT BD ASSY TOP BOARD WFM90 80009 671 3042 03 671 3042 04 B011803 B022965 1 CIRCUIT BD ASSY TOP BOARD WFM90 80009 671 3042 04 671 3042 05 B022966 B023841 1 CIRCUIT BD ASSY TOP BOARD WFM90 80009 671 3042 05 8 6 WFM 90 and WFM 91 Service Manual Replaceable Parts List Replaceable Parts List Cont Fig amp Index Tektronix Number Part Number 671 3042 06 671 3264 01 671 3264 02 671 3264 03 671 3264 04 671 3264 05 39 119 4788 00 40 119 4789 00 41 150 0215 00 070 8968 00 070 8968 01 070 8968 02 070 8968 03 070 8968 01 070 8968 02 070 8968 03 42 119 4538 00 119 5507 00 119 4538 00 119 5507 00 016 1330 00 070 8969 03 070 8969 03 276 0838 00 386 6787 00 011 0167 00 Serial No Effective B023842 B010100 B010185 B010525 B020840 B021091 B010100 B010353 B021958 B022966 B010100 B020561 B020840 B010100 B021958 B010100 B020561 B030871 B030220 B020561 Serial No Discont d B010184 B010524 B020839 B021090 B010352 B021957 B022965 B020560 B020839 WFM 90 and WFM 91 Service Manual Qty amp Description CIRCUIT BD ASSY TOP BOARD WFM90 CIRCUIT BD ASSY TOP BOARD WFM91 CIRCUIT BD ASSY TOP BOARD WFM91 CIRCUIT BD ASSY TOP BOARD WFM91 CIRCUIT
15. BD ASSY TOP BOARD WFM91 CIRCUIT BD ASSY TOP BOARD WFM91 KEYPAD ELASTOMERIC FRONT PANEL 17 KEY DISPLAY MODULE LCD 234V X 479H 4 INCH COLOR NTSC PAL BACKLIGHT ANALOG RGB IN LAMP BACKLIGHT FLUORESCENT REPLACEMENT FOR 4 IN SHARP STANDARD ACCESSORIES MANUAL TECH USERS WFM90 MANUAL TECH USERS WFM90 MANUAL TECH USERS WFM90 MANUAL TECH USERS WFM90 MANUAL TECH USERS WFM91 MANUAL TECH USERS WFM91 MANUAL TECH USERS WFM91 POWER SUPPLY 12W 12V 1 0A UNREGULATED 120VAC 60HZ 183CM CABLE W 5 5MM OD 2 1MM ID RT ANG CN C STANDARD WFM90 AC ADAPTER ASSY AC ADAPTER W NOISE FILTER STANDARD WF M90 POWER SUPPLY 12W 12V 1 0A UNREGULATED 120VAC 60HZ 183CM CABLE W 5 5MM OD 2 1MM ID RT ANG CN C STANDARD WFM91 AC ADAPTER ASSY AC ADAPTER W NOISE FILTER STANDARD WFM91 CASE CARRYING DUAL ZIPPER TEK LOGO IN VINYL HAND STRAP BELT HOOP TRI RING CLEAR VINYL FRONT OPTIONAL ACCESSORIES MANUAL TECH SERVICE WFM90 MANUAL TECH SERVICE WFM91 CORE EM HALF EMI SUPPRESS IMPED 298 OHM AT 100MHZ PKG 2 HALFS W CLAMP 0 705 X 0 725 1 28 L WFM91 STAND FLIP METAL COVER HOOD PLASTIC Mfr Code 80009 80009 80009 80009 80009 80009 80009 TK1416 TK1416 80009 80009 80009 80009 80009 80009 80009 14310 80009 14310 80009 80009 80009 80009 83285 80009 80009 Mfr Part Number 671 3042 06 671 3264 01 671 3264 02 671 3264 03 671 3264 04 671 3264 05 119 4788 00 LQ4RA02
16. DSYNC signal is bad replace the Top board oard If the SEL_EXVID signal is bad replace the Top board If the RGB video is bad replace the Bottom board If the Raster Drive signals are bad replace the Top board Are all of the Backlight power supply pu good Yes Replace the Backlight board No Replace the Bottom board 6 37 Troubleshooting Procedures Use this procedure when the graticule is ok butthe Waveform display is distorted or not visible Remove the Display module and Backlight board Power up the instrument and select DEFAULT PRESETs from the CONFIGURE menu Select the Waveform display mode Check the VIDEO IN signal 114 2 21 3 Vpp 0 VDC blanking level Check the input DC clamp circuit Bottom board with a jumper wire Check the VIDEO IN signal J 14 2 1 3 Vpp 0 3 VDC blanking level Check the Waveform display mode horizontal and vertical deflection signals J 9 is on the back of the Top board 194 213 2 VDC vert 193 222 Vpp 2 3 VDC horiz Are the deflection signals ok Replace the Bottom board Check the horizontal and vertical size control voltages These voltages are set in the CALIBRATION MENU J9 7 20 9 VDC 9 8 1 2 VDC Are the size voltages ok Replace the Top board Replace the Bottom board Figure 6 18 Flowchart for distorted waveform display 6 38 Short J 14 4 to the GND
17. Procedures Equipment Required Table 5 2 lists the required equipment and accessory items to perform the adjustment procedures Minimum equipment specifications are followed by an example of equipment that meet these specifications Table 5 2 Equipment required for performance verification Minimum Requirements Equipment Example Equipment Description Television test signal generator 75 color bar test signal forthe television standard of the monitor to be tested NTSC Tektronix TSG 100 PAL Tektronix TSG 111 Leveled sine wave generator Output Level Range 11 55 dBm 200 mV to 0 43 dBm 800 mV Frequency 50 kHz to 10 MHz Tektronix SG 5031 Leveled Sine Wave Generator Function generator Audio generator Voltmeter Frequency counter Video amplitude calibrator VAC Peak to peak detector 75 Q terminator 15 coaxial cable 50 coaxial cable Dual input coupler Audio cable 50 Q to 75 Q minimum loss attenuator Range 0 1 to 5 Vpp when loaded by 75 Q 10 Vpp when unloaded Frequency 50 kHz to 10 MHz Amplitude Range 10 dBu to 8 dBu Frequency 1 kHz to 50 kHz Range 0 VDC to gt 100 VDC Accuracy 0 1 Range 10 Hz to 10 MHz Accuracy 0 00196 Signal Adjustable square wave 0 0 mVpp to 999 9 mVpp Resolution 0 1 mV Accuracy 0 0596 Frequency Approximately 270 Hz Input Signal Range 0 25 Vpp to 1 0 Vpp Flatness 0 2 50 kHz to 10 MHz Input Impedance 75
18. Service training questions may require specialists who are only available between 8 am 5 pm Pacific time Before You Begin This manual is for servicing the WFM90 or WFM91 Handheld Waveform Vector Picture and Audio Monitor To prevent injury to yourself or damage to the instrument do the following tasks before you attempt service m Besure you are a qualified service person m Read the Safety Summary found at the beginning of this manual m Read Service Strategy in this section When using this manual for servicing be sure to heed all warnings cautions and notes WFM 90 and WFM 91 Service Manual xvii Introduction xviii WFM 90 and WFM 91 Service Manual SM Specifications 7 a 0 Specifications This section includes the following information Product description m Characteristics tables Refer to Performance Requirements on page 1 5 for the conditions over which the characteristics listed in this section are valid Product Description The Tektronix WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor is a self contained rasterizing television monitor The instrument has a built in LCD color display device and is powered by batteries or by an AC adapter producing 12 VDC This product can be used in traditional in house applications of television production post production and signal transmission The portability of this instrument allows it to
19. and Lum low pass filters by more than 1 1 V Full Scale 1 V input displayed within 1 of 140 IR E REF Flatfilter selected X5 Gain Gain accuracy within 5 with 1 V input signal REF X5 Gain Registration lt 1 major division of vertical shift from baseline between unmagnified and magnified signal Variable Gain Range Input signals between 0 8 V and 2 V can be adjusted to 140 IRE 1 0 V display 160 mV to 400 mV for X5 Gain Position Range 1 V signal can be positioned so that peak white and sync tip can be placed at blanking level with the DC Restorer on regardless of gain setting REF Specifications apply for full screen height video input signal with Vari able Gain off 1 V Full Scale or X5 Gain selected and Flat filter se lected REF Pulse to Bar Ratio X1 0 99 1 to 1 01 1 X5 0 98 1 to 1 02 1 REF Preshoot x 196 REF Overshoot x 296 X5 x 496 REF Ringing x 296 X5 x 496 REF Field Rate Tilt 196 REF Line Rate Tilt lt 19 Overscan x 2 variation in baseline of 100 IRE 700 mV 12 5T 20T modulated pulse as itis positioned over the middle 8096 of the screen REF 5 plus peak AC REF Displays in excess of 200 IRE 1 428 V may cause frequency re sponse aberrations WFM 90 and WFM 91 Service Manual Specifications Table 1 1 Vertical deflection system Cont Category DC Input Impedance Unterminated Video Input Return Loss Video Out Return Lo
20. battery contacts To replace the battery power connector perform the following procedure 1 Solder the battery power connector wires to the battery contacts See Figure 6 12 2 Install the bottom cover Refer to Bottom Cover on page 6 23 Battery Contacts To remove the battery contacts perform the following procedure 1 Remove the bottom cover Refer to Bottom Cover on page 6 23 2 Toremove one of the battery contacts that has the battery power connector soldered to it unsolder the battery connector wire before you remove the battery contact 3 Pry the battery contact past the retaining lip on the bottom cover See Figure 6 11 6 24 WFM 90 WFM 91 Service Manual Removal Replacement Alignment ridge Battery contacts Figure 6 11 Battery contact installation alignment 4 Push the battery contact through the slot on the bottom cover To replace the battery contacts perform the following procedure 1 Align the slot in the battery contact with the battery contact alignment ridge on the bottom cover See Figure 6 11 2 Push the battery contact through the slot in the bottom cover until the battery contact snaps past the retaining lip of the bottom cover 3 If you replaced one of the battery contacts that had the battery power wires soldered to it resolder the battery connector wire to the battery contact See Figure 6 12 WFM 90 and WFM 91 Service Manual 6 25 Removal and Replaceme
21. battery cover Refer to Battery Cover on page 6 18 Alkaline Batteries To remove the C size alkaline batteries perform the following procedure 1 Remove the battery cover Refer to Battery Cover on page 6 18 2 Carefully pull the batteries out of the battery compartment 6 22 WFM 90 WFM 91 Service Manual Removal Replacement To replace the C size alkaline batteries perform the following procedure 1 Press the batteries into place according to the polarity label the bottom of the battery compartment See Figure 6 10 NOTE The polarity of the alkaline batteries must be correct for the instrument to operate Always replace all of the alkaline batteries at the same time when replacing discharged batteries Figure 6 10 Installed polarity of alkaline batteries 2 Install the battery cover Refer to Battery Cover on page 6 18 Bottom Cover Assembly bottom cover assembly contains replaceable subparts Procedures for removing and installing the s
22. be used in untraditional applications such as field production and system maintenance Key Features following is a list of the key features of this instrument m Rasterized waveforms and graticules shown on the built in color four inch diagonal TFT LCD display with viewing angle adjustment W Powered by batteries or an AC adapter W Menu assisted monitoring operation m Video and audio signal input and output capability m Waveform Vector Picture Audio and Waveform in Picture WIP display modes m Line Select mode for the selection of any single line of video for display m Time out mode to shut off power to the display backlight and or the instrument when the instrument is not in use m Signal level alarm mode for the waveform and audio displays m Preset menu to store or recall the front panel and menu setup m Instrument readjustment is performed entirely from the front panel WFM 90 and WFM 91 Service Manual 1 1 Specifications Description of Key Features The key features of this instrument are described below Rasterized Color LCD Display This instrument uses a color four inch diagonal backlit thin film transistor TFT LCD raster display module The proprietary rasterizer displays analog waveforms or vectors simultaneously with the appropriate measurement graticules A viewing angle control for the display permits optimal signal viewing from different positions The LCD display retains an image if the ins
23. distance from the center represents chrominance amplitude The vector display is useful when making differential gain and phase measurements A full 360 phase shifter and 75 and 100 color bar settings are provided Vector gain is fixed at X1 or X5 or is variable from 45 to 155 amplitude The gain setting tracks between the Waveform and Vector display modes The V mode PAL only overlays the V axis on the V axis to check the PAL system color encoders Picture Display Mode The Picture display mode provides an unprocessed full color display of the composite video signal The NTSC Safe Action and Safe Title areas as well as the PAL Safe Area can be highlighted The vertical interval portion of the signal can be viewed by vertically shifting the display Controls for adjusting the hue and color of the picture display are provided Audio Display Mode The Audio display mode provides a voltage versus time display of a single audio channel The audio voltage is displayed on the vertical scale with time on the horizontal scale at a two field sweep rate Audio reference levels can be set to 10 dBu 0 dBu 4 dBu or 8 dBu with an additional level available for microphone checks The audio headroom reference level can be set to 3 dB or 10 dB is for audio signals below or above the reference level respectively WFM 90 and WFM 91 Service Manual 1 3 Specifications 1 4 More Information Waveform in Picture Display M
24. horizontal and vertical deflection signals to produce the waveforms The rasterizer uses the horizontal and vertical sync signals from the Bottom board to lock to the incoming video signal The rasterizer needs a good analog timing voltage to run correctly This timing voltage is generated by a circuit loop between the Top and Bottom boards Problems with this circuit can be on either circuit board Bottom Board Bottom board contains the power supply circuitry the horizontal and vertical deflection circuits the NTSC or PAL decoder the vectorscope and burst lock circuitry the sync separator and the audio amplifier for the headphone output WFM 90 and WFM 91 Service Manual 3 1 Theory of Operation Backlight Power Supply Board LCD Display and Backlight The Backlight Power Supply board uses the switched DC input voltage from the batteries or external DC input to generate the voltage for the display backlight The backlight mounts into the display module The LCD Display module generates the display graphics using input signals generated on the Top and Bottom boards The power for the LCD Display module comes from the Bottom board while the power for the backlight comes from the Backlight Power Supply board The display backlight mounts into the side of the LCD Display module WFM 90 and WFM 91 Service Manual Theory of Operation Input Board Bottom Board Video Out V
25. inches x 6 inches inside 14 inches x 14 25 inches x 6 25 inches outside REF With batteries and pouch 3 105 9 oz Without batteries and pouch 1 lb 14 oz Shipping weight with packaging 5 105 14 07 Description REQ REQ REQ REQ REQ To 15 000 feet 4572 meters REF 1010 1 compliance to 2000 meters 0 to 450 C REF EC 1010 1 compliance to 40 C Measurement Installation Category as defined in IEC 1010 1 Annex REF Rated for indoor use only Pollution Degree 2 as defined in IEC 1010 1 WFM 90 and WFM 91 Service Manual Specifications Table 1 8 Environmental characteristics Cont Description Category Vibration Operating Shock Non Operating Transportation Humidity Table 1 9 Power source Category Battery Battery Charge Time Power Consumption Operating Time External Power WEM 90 and WFM 91 Service Manual REF 15 minutes each axis at 0 015 inch frequency varied from 10 Hz to 55 Hz to 10 Hz in 1 minute cycles with instrument secured to vibration platform Ten minutes each axis at any resonant point or at 55 Hz if no resonant point is found REF 100 g 1 2 sine 11 ms duration 3 shocks per surface 18 total REF Qualified under NTSC Test Procedure 1A Category 24 inch drop REF Will operate at 9596 relative humidity for up to five days Meets the five day cycling humidity test as called out in Tektronix standard 062 28
26. is enabled through the Configuration menu For the Waveform display mode the portion of the signal exceeding the 100 IRE 1 0 V PAL graticule line is highlighted For the Audio display mode the portion of the signal exceeding the menu selected reference level is highlighted The highlighted portion of the signal is also visible in the Waveform in Picture WIP display mode Variable Gain Mode The Variable Gain mode allows you to vary the signal gain for the Waveform and Vector displays between 45 and 155 This mode is enabled through the Configuration menu The variable gain adjustment tracks between the Waveform and Vector display modes and can be adjusted from the Waveform in Picture display mode When the Variable Gain mode is enabled the message GAIN UNCAL is displayed in the on screen readout Time out Mode The Time out mode allows you to automatically shut down the backlight and or the instrument after there has been no front panel activity for a menu selected length of time The Time out mode enables you to reduce battery power usage while the instrument is battery powered and also to extend the life of the backlight bulb This mode is enabled through the Configuration menu When the backlight times out the LCD display goes blank and the instrument appears to be off The backlight is turned back on by pressing any front panel button other than the ON button The backlight shutdown is functional when the instrument is either batt
27. message appears in the Waveform and Vector display modes when the video signal is locking to an external video reference signal m The sweep rate is only displayed in the Waveform display mode There is no sweep rate readout when 2 Field sweep is selected WFM 90 and WFM 91 Service Manual 2 9 Operating Information Default Settings m The instrument software version number is displayed when the Configura tion menu is open with the DISPLAY category selected m The LOW BAT message is displayed when the instrument is battery operated and the remaining battery power has reached a critically low level The remaining length of time that the instrument can be operated reliably is dependent on the current operating mode m The MISSING SYNC message appears in all video display modes when the signal reference has been lost You can reset the front panel and menu settings to the factory specified default settings through the Configuration menu Monitoring adjustments such as signal position vector phase and picture hue are also set The factory settings are listed Table 2 1 Table 2 1 Front panel and menu default settings Instrument Parameter Factory Default Setting Display mode Waveform Signal reference Internal Filter Flat DC restorer speed Slow Gain X1 Variable gain Off Sweep 2H 2 Line Mag Off Bars 15 Setup 90 only Yes Alt Phase WFM 91 only Off Reference dBu 0 dBu Headroom 3
28. modes are bad or not visible after the instrumentis turned on Replace the Top Board first These problems can be caused by either the Top or Bottom boards and can only be determined by replacing these boards one at a time Figure 6 28 Flowchart for problems with the instrument controls WFM 90 and WFM 91 Service Manual 6 47 Troubleshooting Procedures 6 48 Use this procedure when the menus are horizontally unlocked tearing in the Picture display mode Does the Yes input signal have Correct the problem on the input signal noisy sync Check the horizontal and vertical sync signals on the Bottom board J 9 is on Top board 19 18 VSYNC is a TTL Level locked to Video IN V sync 19 19 HSYNC is a TTL Level locked to VIDEO IN H sync Are the VSYNC and HSYNC signals good and locked to the video input signal Replace the Top board Replace the Bottom board Figure 6 29 Flowchart for bad menus in the picture display WFM 90 and WFM 91 Service Manual Troubleshooting Procedures Use this procedure when the display is dim or blotchy Replace the Backlight inthe Display module Figure 6 30 Flowchart for dim or blotchy display Use this procedure when all ofthe display modes are bad except Picture when no menus are displayed Replace the Top board Figure 6 31 Flowchart for bad displays except Picture mode WFM 90 and WFM 91 Service Manual 6 49
29. rose Figure 4 1 3 dB marks on the vector graticule 10 Check that the frequency readout on the leveled sine wave generator is between 2 98 and 3 18 MHz 3 83 and 4 03 MHz PAL Adjust the frequency on the leveled sine wave generator until the edge of the circle display reaches the 3 dB 70 point gaps on the horizontal graticule axis Check that the frequency readout on the leveled sine wave generator is between 2 98 and 3 18 MHz 3 83 and 4 03 MHz PAL Increase the frequency on the leveled sine wave generator until the edge of the circle display expands out to the compass rose and again reduces to the 3 dB 70 point gaps on the vertical graticule axis See Figure 4 1 Check that the frequency readout on the leveled sine wave generator is between 3 98 and 4 18 MHz 4 83 and 5 03 MHz PAL Adjust the frequency on the leveled sine wave generator until the edge of the circle display reaches the 3 dB 70 point gaps on the horizontal graticule axis WFM 90 and WFM 91 Service Manual Performance Verification 11 12 Remove all signals from the WFM 90 or WFM 91 Handheld Waveform Check that the frequency readout on the leveled sine wave generator is between 3 98 and 4 18 MHz 4 83 and 5 03 MHz PAL Vector Picture and Audio Monitor Audio Gain and This procedure verifies the following requirement Frequency Response Measurement Accuracy 0 5 dB at 1 KHz Frequency Response 0 5 dB from 5
30. shield in place above the inside of the bottom cover before you press it onto the bottom cover Be sure to align the hole in the shield with the hole in the bottom cover 3 Rub your fingers over the shield once it is positioned on the bottom cover to make sure the pad is securely in place 4 Install the bottom cover Refer to Bottom Cover on page 6 23 Battery Orientation Marker and Battery Cushion Pad To remove the battery orientation marker and or the battery cushion pad perform the following procedure 1 Remove the battery cover Refer to Battery Cover on page 6 18 2 Toonly remove the battery orientation marker pry it up around the edges and peel it off of the battery cushion pad on the bottom cover 3 remove both the battery orientation marker and the battery cushion pad pry the battery cushion pad up around the edges and peel it off of the bottom COVer 4 If necessary clean the surface of the battery cushion pad or the bottom cover to remove any remaining glue residue Refer to Cleaning on page 6 3 WFM 90 and WFM 91 Service Manual 6 27 Removal Replacement To replace the battery orientation marker and or the battery cushion pad perform the following procedure 1 To replace the battery cushion pad and the battery orientation marker peel off the protective covering of the adhesive surface of the battery cushion pad 2 Position the battery cushion pad in place above the bottom cover before you
31. signal or external reference signal REF Pull In Time Within 1 second with subcarrier frequency within 50 Hz 10 Hz for PAL of Fsc NTSC 2 from Fsc to Fsc 50 Hz or Fcc to 50 Hz PAL 2 from Fcc to Fsc 10 Hz orFsc to 10 Hz 2 from nominal burst amplitude to 6 dB REF Internal or External burst reference 1 as gain is varied from 3 dB to 6 dB REF 360 continuous rotation REF 0 5 RMS orless REF With 140 IRE 1 V composite video input INT or EXT referenced Specifications Table 1 6 Synchronization Category Input Requirements External Reference Input Table 1 7 Physical characteristics Category Dimensions Weight Table 1 8 Environmental characteristics Category Operating Altitude Operating Temperature Equipment Type Installation Category Pollution Degree 1 10 Description REQ REQ REQ Internal Reference Composite video or black burst with sync amplitudes 40 IRE 300 mV PAL 6 dB External Reference Sync amplitude between 143 mV and 4 V will synchro nize sweeps DC Input Impedance unterminated 15 kQ REF Return Loss 75 Q gt 40 dB from 50 kHz to 6 MHz with 75 Q ter mination on instrument power on REF Absolute Maximum Input Voltage 12 VDC plus peak Description REF Instrument 5 inches 127 mm 3 15 inches 80 0 mm 9 6 inches 243 8 mm Shipping Box 13 25 inches x 13 75
32. to Default Settings on page 2 10 for a list of the default settings Instrument Readjustment This instrument can be adjusted entirely from the front panel after entering the Calibration menu Instructions for adjusting the instrument are located in the Adjustment Procedures section of this manual The location of some additional information is listed below m Refer to Battery Operation on page 2 3 for information on operating the instrument with batteries m Front panel operation is described in the Operating Information section m Instrument options are listed in the Options section m Standard and optional accessories are listed in the Replaceable Mechanical Parts section WFM 90 and WFM 91 Service Manual Specifications Characteristics Tables The characteristics tables use the following abbreviations Performance Requirement performance requirements in the characteristics tables are identified with Req and can be assured by performing the procedures in the Performance Verification section Allow a warm up time of 20 minutes before performing the procedures Performance requirements in the electrical specifications are valid over an ambient temperature range of 20 C to 30 C The Performance Requirement tolerances listed in the electrical specifications are doubled over the temperature range of 0 C to 40 C unless otherwise specified Test equipment used to verify performance requirements must be calibrated and
33. to the Arrow Buttons through the Calibration menu Conventions Throughout these procedures the following conventions apply Each adjustment procedure uses the following format Title of adjustment procedure Adjustment procedure m When you are instructed to use a front panel control or to select a specific menu item of the WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor the name of the control or menu item appears in boldface type NOTE Do not make changes to the front panel settings or controls that are not called out in the procedures Each procedure will require you to set the instrument to certain default settings before an adjustment is made If you make changes to these settings other than those called out in the procedure you may incorrectly adjust your instrument The adjustment procedures are written in a format that assumes you are performing the procedures in sequential order from the beginning If you are unsure about equipment hookups or instrument settings for a specific procedure you will need to review the previous procedures to verify the hookups and settings required for the current procedure Prerequisites The adjustments in this section comprise a valid readjustment of instrument performance when the following requirements are met m Test equipment used to verify performance requirements must be calibrated and working within the limits specified in Table 5 2 on page 5 2 The WFM
34. 0 Hz to 20 kHz 1 10 12 13 14 Connect the output from the audio generator to the AUDIO IN connector on the WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor Set the audio generator for a 1 KHz tone output with an amplitude of 8 0 dBu Select Signal On Select AUDIO display mode on the WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor Enter the Operating menu and select 8 dBu Check that the display amplitude is within 0 5 dB of the reference level graticule lines Set the audio generator for a 4 0 dBu output amplitude Select 4 dBu from the Operating menu Check that the display amplitude is within 0 5 dB of the reference level graticule lines Set the audio generator for a 0 0 dBu output amplitude Select 0 dBu from the Operating menu Check that the display amplitude is within 0 5 dB of the reference level graticule lines Set the audio generator for 10 0 dBu output amplitude Select 10 dBu from the Operating menu Check that the display amplitude is within 0 5 dB of the reference level graticule lines WFM 90 WFM 91 Service Manual 4 13 Performance Verification 15 Set the audio generator for a 50 Hz tone output with an amplitude of 8 0 dBu 16 Select 8 dBu from the Operating menu 17 Check that the display amplitude is within 0 5 dB of the reference level graticule lines 18 Set the audio generator frequency to 5 kHz
35. 0 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor m Option Al 220 V Wall Unit Power Adapter European TUV m Option A2 240 V Wall Unit Power Adapter UK m Option 240 V Wall Unit Power Adapter Australia m Option 100 V Wall Unit Power Adapter Japan m Option M2 5 years Warranty Remedial Service m Option M8 4 Calibration Performance Tests m Option 33 Travel line package which includes m NiCad battery pack m Viewing hood m Desk flip stand Carrying case used for carrying this instrument and Pathfinder TSG 90 Series Signal Generator WFM 90 and WFM 91 Service Manual 7 1 Options and Accessories Accessories The standard accessories are shipped with every instrument while the optional accessories must be ordered separately The part numbers to use when you order any of the following accessories are listed in Mechanical Parts List on page 8 7 Standard Accessories The standard accessories for the WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor are listed below m WFM 90 WFM 91 Handheld Waveform Vector Picture and Audio Monitor User Manual m 120 V Wall Unit Power Adapter North American m Carrying pouch Optional Accessories optional accessories available for the WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor are listed below m WFM 90 and WFM 91 Handheld Waveform Vector Picture and Audio Monitor S
36. 002 MATTE SILVER 80009 334 8830 00 POLYESTER BLACK NOMENCLATURE 30 348 1427 00 1 PAD CUSHIONING PAD CUSHIONING BATTERY 80009 348 1427 00 31 202 0339 00 1 5 1 80009 202 0339 00 32 337 4036 00 1 SHIELD ELEC 0 005 VALOX W 0 005 254 PRESSURE 80009 337 4036 00 SENSITIVE ADHESIVE BACKSIDE 2 050 X 4 650 33 214 4627 00 2 SPRING CONTACT BATTERY CONTACT SINGLE 80009 214 4627 00 34 214 4628 00 5 SPRING CONTACT SPRING BATTERY 80009 214 4628 00 CONTACT DUAL 35 174 3289 00 1 CA ASSY SP DISCRETE CPD 2 24 AWG TEFLON 80009 174 3289 00 4 3 L 1X2 0 079 CTR 2MM PLZ BOTH ENDS JSTTYPE 36 671 3043 00 B010100 B011122 1 CIRCUIT BD ASSY BOTTOM BOARD WFM90 80009 671 3043 00 671 3043 01 B011123 B011362 1 CIRCUIT BD ASSY BOTTOM BOARD WFM90 80009 671 3043 01 671 3043 02 B011363 B023820 1 CIRCUIT BD ASSY BOTTOM BOARD WFM90 80009 671 3043 02 671 3043 03 B023821 1 CIRCUIT BD ASSY BOTTOM BOARD WFM90 80009 671 3043 03 671 3263 00 B010100 B010358 1 CIRCUIT BD ASSY BOTTOM BOARD WFM91 80009 671 3263 00 671 3263 01 B010359 B010470 1 CIRCUIT BD ASSY BOTTOM BOARD WFM91 80009 671 3263 01 671 3263 02 B010471 B021056 1 CIRCUIT BD ASSY BOTTOM BOARD WFM91 80009 671 3263 02 671 3263 03 B021057 1 CIRCUIT BD ASSY BOTTOM BOARD WFM91 80009 671 3263 03 37 337 4035 00 1 SHIELD ECB ECB SHIELD ALUM 80009 337 4035 00 38 671 3042 00 B010100 B010109 1 CIRCUIT BD ASSY TOP BOARD WFM90 80009 671 3042 00 671 3042 01 B010110 B010502 1 CIRCUIT BD
37. 00801 070 8968 00 070 8968 01 070 8968 02 070 8968 03 070 8968 01 070 8968 02 070 8968 03 P48121000A220CM 119 5507 00 P48121000A220CM 119 5507 00 016 1330 00 070 8969 03 070 8969 03 28A2025 010 386 6787 00 011 0167 00 8 7 Replaceable Parts List Replaceable Parts List Cont Fig amp Index Number Tektronix Part Number 016 1344 00 119 4540 00 119 5424 00 119 4540 00 119 5424 00 119 4541 00 119 5423 00 119 4541 00 119 5423 00 119 4542 00 119 5421 00 119 4542 00 119 5421 00 119 4539 00 119 5508 00 119 4539 00 119 5508 00 8 8 Serial No Effective 021958 020561 021958 020561 021958 020561 021958 020561 Serial No Discontd Qty amp Description CASE CARRYING CUSTOM CASE FOR WFM90 TSG90 POWER SUPPLY 12W 12V 1 0A UNREGULATED 220VAC 50HZ 183CM CABLE W 5 5MM OD 2 1MM ID RT ANG CN C EUROPEAN WFM90 AC ADAPTER ASSY AC ADAPTER W NOISE FILTER EUROPEAN WFM90 POWER SUPPLY 12W 12V 1 0A UNREGULATED 220VAC 50HZ 183CM CABLE W 5 5MM OD 2 1MM ID RT ANG CN C EUROPEAN WFM91 AC ADAPTER ASSY AC ADAPTER W NOISE FILTER EUROPEAN WFM91 POWER SUPPLY 12W 12V 1 0A UNREGULATED 240VAC 50HZ 183CM CABLE W 5 5MM OD 2 1MM ID RT ANG CN C UNITED KINGDOM WFM90 AC ADAPTER ASSY AC ADAPTER W NOISE FILTER UNITED KINGDOM WFM90 POWER SUPPLY 12W 12V 1 0A UNREGULATED 240VAC 5
38. 0HZ 183CM CABLE W 5 5MM OD 2 1MM ID RT ANG CN C UNITED KINGDOM WFM91 AC ADAPTER ASSY AC ADAPTER W NOISE FILTER UNITED KINGDOM WFM91 POWER SUPPLY 12W 12V 1 0A UNREGULATED 240VAC 50HZ 183CM CABLE W 5 5MM OD 2 1MM ID RT ANG CN C AUSTRALIAN WFM90 AC ADAPTER ASSY AC ADAPTER W NOISE FILTER AUSTRALIAN WFM90 POWER SUPPLY 12W 12V 1 0A UNREGULATED 240VAC 50HZ 183CM CABLE W 5 5MM OD 2 1MM ID RT ANG CN C AUSTRALIAN WFM91 AC ADAPTER ASSY AC ADAPTER W NOISE FILTER AUSTRALIAN WFM91 POWER SUPPLY 12W 12V 1 0A UNREGULATED 100VAC 50HZ 183CM CABLE W 5 5MM OD 2 1MM ID RT ANG CN C J APANESE WFM90 AC ADAPTER ASSY AC ADAPTER W NOISE FILTER J APANESE WFM90 POWER SUPPLY 12W 12V 1 0A UNREGULATED 100VAC 50HZ 183CM CABLE W 5 5MM OD 2 1MM ID RT ANG CN C J APANESE WFM91 AC ADAPTER ASSY AC ADAPTER W NOISE FILTER J APANESE WFM91 Mfr Code 80009 14310 80009 14310 80009 14310 80009 14310 80009 0GV90 80009 0GV90 80009 14310 80009 14310 80009 Mfr Part Number 016 1344 00 D48121000A220CM 119 5424 00 D48121000A220CM 119 5424 00 F48121000A220CM 119 5423 00 F48121000A220CM 119 5423 00 WD377E1000CRA12C N 119 5421 00 WD377E1000CRA12C N 119 5421 00 G48121000A220DM 119 5508 00 G48121000A220DM 119 5508 00 WFM 90 and WFM 91 Service Manual EU dE Diagrams Diagrams This section contains the interconnec
39. 47 00 Description REQ REF 6 C sized cell batteries or Tektronix NiCad battery pack Tektronix Part Number 146 0107 00 REF FastCharge 550 REF Slow Charge 150 mA REF Picture Mode 55W WaveformMode 7 2W Vector Mode 71 2W REF Alkaline Batteries Picture Mode 2 5 hours Waveform Mode 2 hours Vector Mode 2 hours NiCad Batteries Picture Mode 4 hours Waveform Mode 3 hours Vector Mode 3 hours REF Fully charged or new batteries DC Source of 11 V to 18 V REF Wall Unit Tektronix Part Numbers 220V European TUV 119 4540 00 240 V UK 119 4541 00 240 V Australia 119 4542 00 100 V J apan 119 4539 00 120 V North America 119 4538 00 Specifications Table 1 10 Safety EMI Category Description Certifications REQ Designed to meet or exceed ANSI ISA S82 Safety Standard for Electrical and Electronic Test Measur ing Controlling and Related Equipment CAN CSA C22 2 No 1010 1 92 Safety Requirements for Electrical Equip ment for Measurement Control and Laboratory Use IEC1010 1 Safety Requirements for Electrical Equipment for Measure ment Control and Laboratory Use 1990 113111 Standard for Electrical Measuring and Test Equipment EMI Compliance REQ Designed to meet or exceed U S FCC 47 CFR Part 15 Subpart B Class A EC Declaration of Conformity Meets intent of Directive 89 336 EE C for Electromagnetic Compatibility Compliance was demonstrated to the following sp
40. 5 POS from the Calibration menu and then select CAL 13 Select X1 GAIN and then position the signal baseline to the graticule baseline WFM 90 and WFM 91 Service Manual Adjustment Procedures 14 15 16 17 18 Select X5 GAIN from the Calibration menu and then select X5 POS Adjust the Arrow Buttons to reposition the signal baseline back to the graticule baseline Select X1 GAIN from the Calibration menu Select CAL MENU and then select SAVE Remove the signal and terminator from the VIDEO IN connector Frequency Response Perform the following steps to adjust the frequency response 1 10 11 12 13 14 15 Connect a 50 precision cable from the output of the leveled sine wave generator to the dual input coupler using a 50 2 to 75 Q minimum loss attenuator Connect one side of the dual input coupler to the VIDEO IN connector Connect the 015 0413 00 Peak to Peak Detector Head to the other end of the dual input coupler using the female to female BNC connector Connect the other end of the Peak to Peak Detector Head to the 015 0408 00 Peak to Peak Detector Input Connect the peak to peak detector Output to the digital multimeter or an oscilloscope Select EXT REF from the Configuration menu Set the leveled sine wave generator frequency to 50 and adjust the generator amplitude for exactly 100 IRE 700 mV PAL of display Adjust the peak to peak detector Plus amplifier and i
41. 96 of the screen Input and DC restorer frequency response X1 Gain Response Flat filter selected 50 kHz to 6 MHz within 296 of response at50 kHz X5 Gain Response Flat filter selected 50 kHz to 6 MHz within 5 of response at 50 kHz Attenuation of 60 Hz 50 Hz PAL on Input Signal SLOW mode 20 FAST mode 9096 WFM 90 and WFM 91 Service Manual 4 1 Performance Verification Table 4 1 Summary verification procedure Cont Procedure Procedure Requirement Vector phase stability Phase Shift with 5 ubcarrier Frequency Change from Fsc to Fsc 50 Hz 10 Hz PAL 2 Phase Shift with Burst Amplitude Change from Nominal to 6 dB 2 Phase Shift with Variable Gain Control Varied from 3 dB to 6 dB 1 Chrominance bandwidth Chrominance Bandwidth Upper 3 dB Point 500 kHz 100 kHz 4 Lower 3 dB Point 500 kHz 100 kHz Audio gain and frequency response Measurement Accuracy 0 5 dB at 1 kHz Frequency Response 0 5 dB 4 13 from 50 Hz to 20 kHz Equipment Required Table 4 2 lists the required equipment and accessory items to perform the performance verification procedures Minimum equipment specifications are followed by an example of equipment that meet these specifications An accuracy ratio of 4 1 or better for the warranted specifications will be obtained using the equipment recommended in Table 4 2 with the following exceptions m Audio Amplitude 2 5 1 m A
42. EO OUT connector is a BNC used to output the instrument display to a remote monitor or video switcher Audio Input and Output Connectors The AUDIO IN connector is a standard three pin XLR connector for a single channel of audio input The audio output connector is a standard stereo mini headphone jack for the output of the audio input signal The mono input signal is heard on both stereo channels The audio volume is fixed for each reference level The larger the displayed signal the louder the volume WFM 90 and WFM 91 Service Manual Operating Information AUDIO IN DC IN 11 18V Figure 2 4 Instrument side panels DC Input Power Connector The DC IN power connector is a 2 mm plug which accepts a 12 VDC power input ranging from 11 V to 18 V using a negative center lead CAUTION To avoid possible damage to the instrument circuitry when using a DC N power source other than the supplied AC adapter ensure that the DC source is a negative ground 11 V to 18 V system with a negative center lead The DC source should be able to provide 12 W of power WFM 90 and WFM 91 Service Manual 2 7 Operating Information Special Operating Modes 2 8 The following special operating modes can be activated through the menus Amplitude Alarm Mode The Amplitude Alarm mode provides a means to automatically monitor the signal amplitude for the Waveform and Audio displays This mode
43. Figure 6 12 Battery power wire and turnlock stud receptacle installation 42 cree Tre 6 26 Figure 6 13 Battery orientation marker position 6 28 Figure 6 14 Installing the EMI suppressor 6 29 Figure 6 15 Testing the battery charging circuit WFM 90 SN B011362 and below WFM 91 SN 010470 and below 6 32 Figure 6 16 Testing the battery charging circuit WFM 90 SN B011363 and above WFM 91 SN B010471 and above 6 33 Figure 6 17 Flowchart for no display 6 37 Figure 6 18 Flowchart for distorted waveform display 6 38 Figure 6 19 Flowchart for no vector display 6 39 Figure 6 20 Flowchart for bad audio display 6 40 Figure 6 21 Flowchart for no picture display 6 41 Figure 6 22 Flowchart for bad graticules and menus 6 42 WFM 90 and WFM 91 Service Manual iii Table of Contents Figure 6 23 Flowchart for all white display 6 43 Figure 6 24 Flowchart for untriggered waveform display 6 44 Figure 6 25 Flowchart for unlocked vector display 6 45 Figure 6 26 Flowchart for vector display jitter 6 46 Figure 6 27 Flowchart for distorted vectors 6 46 Figure 6 28 Flowchart for problems with the instrument controls 6 47 Figure 6 29 Flowchart for
44. HVALE 07647 2303 PORTLAND OR 97214 4657 GAITHERSBURG MD 20879 MINNEAPOLIS MN 55428 HAY WARD 94544 COLD SPRINGS KY 41076 DES PLAINES IL 60016 3049 BEAVERTON OR 97077 0001 CHATTANOOGA TN 37401 0510 ROCKFORD IL 611045181 CONCORDVILLE PA 19331 INDIANAPOLIS IN 46268 OSAKA J APAN GIG HARBOR WA 98332 8 3 Replaceable Parts List Figure 8 1 Exploded view 8 4 WFM 90 and WFM 91 Service Manual Replaceable Parts List Replaceable Parts List Fig amp Index Number 10 1 2 WFM 90 and WFM 91 Service Manual Tektronix Part Number 202 0338 10 202 0338 20 378 0418 00 348 1436 00 348 1437 00 174 3287 00 131 5148 00 211 0294 00 131 5798 00 348 1442 00 348 1425 00 159 0378 00 210 0586 00 213 0774 00 220 0497 00 210 1039 00 333 4144 00 671 3044 00 174 3288 00 671 3045 00 671 3045 01 671 3045 02 671 3045 03 671 3045 00 671 3045 01 671 3045 02 Serial No Effective B010100 B011543 B023806 B030000 B010100 B010441 B021045 Serial No Discont d B011542 B023805 B029999 B010440 B021044 B029999 Qty amp Description CASE TOP POLYCARBONATE WFM90 CASE TOP POLYCARBONATE WFM91 FF LP UC LENS DISPLAY POLYCARBONATE CLEAR E HARDCOAT PAD CUSHION CUSHION PAD FOR BACKLIGHT E A R LS1512 PSA20 1 SIDE 0 250 X 3 100 X 0 125 PAD CUSHION LCD CUSHION PAD LCD E A R LS1512 PSA20 1 SIDE 0
45. OVIDED TO THE CUSTOMER FOR BREACH OF THIS WARRANTY TEKTRONIX AND ITS VENDORS WILL NOT BE LIABLE FOR ANY INDIRECT SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES IRRESPECTIVE OF WHETHER TEKTRONIX OR THE VENDOR HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES Service Assurance If you have not already purchased Service Assurance for this product you may do so at any time during the product s warranty period Service Assurance provides Repair Protection and Calibration Services to meet your needs Repair Protection extends priority repair services beyond the product s warranty period you may purchase up to three years of Repair Protection Calibration Services provide annual calibration of your product standards compliance and required audit documentation recall assurance and reminder notification of scheduled calibration Coverage begins upon registration you may purchase up to five years of Calibration Services Service Assurance Advantages W Priced well below the cost of a single repair or calibration W Avoid delays for service by eliminating the need for separate purchase authorizations from your company m Eliminates unexpected service expenses For Information and Ordering For more information or to order Service Assurance contact your Tektronix representative and provide the information below Service Assurance may not be available in locations outside the United States of America Name VISA or Master Card number and expiratio
46. One required feed through type Three cables required male to male BNC connectors 1 precision male to male BNC connectors Matched BNC cable T for making phase comparisons between two inputs Matched length of the two arms within 0 1 inch XLR female to XLR male Impedance 50 O to 75 Tolerance 0 5 dB Frequency 100 MHz Tektronix FG 5031 Function Generator Tektronix ASG 100 Audio Signal Generator Tektronix DM 504 1 Digital Multimeter Tektronix DC 503A1 Universal Counter ktronix part number 067 0916 001 ktronix part number 015 0408 00 includes peak to peak detector head Tektronix part number 015 0413 00 Tektronix part number 011 0103 02 Tektronix part number 012 0159 00 42 inch Tektronix part number 012 1339 00 24 inch Tektronix part number 012 0482 00 36 inch Tektronix part number 067 0525 02 S witchcraft part number S C3XXJ Tektronix part number 011 0057 00 BNC female to BNC female connector Tektronix part number 103 0028 00 BNC female to dual banana adapter Tektronix part number 103 0090 00 1 Requires a Tektronix TM 500 Series or TM 5000 Series Power Module Mainframe WFM 90 and WFM 91 Service Manual Adjustment Procedures Adjustment Procedures The WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor does not have any internal adjustments Instrument adjustments are made entirely from the front panel by assigning adjustment functions
47. Picture and Audio Monitor Such agreements can be purchased to span several years On Site Service The annual maintenance agreement can be purchased with on site service with repair and calibration done at your facility This service reduces the time your instrument is out of service when calibration or repair is required Service Training Tektronix provides service training in a number of programs In addition to classes held at our Beaverton campus special classes at convenient locations can be arranged Tektronix supports repair to the module level by providing Module Exchange and Module Repair and Return Module Exchange This service reduces down time for repair by allowing you to exchange most modules for remanufactured ones Tektronix ships you an updated and tested exchange module from the Beaverton Oregon service center typically within 24 hours Each module has a 90 day service warranty WFM 90 and WFM 91 Service Manual Introduction Module Repair and Return This service returns to you within 10 days the same module that you shipped to Tektronix The module shipped is repaired tested and returned to you from the Beaverton Oregon service center It is not updated to match current modules of the same type Again each module has a 90 day service warranty 1 800 TEK WIDE For more information about any of the Tektronix service offerings US and Canadian customers can call our 24 hour service number at 1 800 TEK WIDE
48. Service Manual Tektronix WFM 90 and WFM 91 Handheld Waveform Vector Picture and Audio Monitor 070 8969 04 This document supports firmware version 1 00 and above Warning The servicing instructions are for use by qualified personnel only To avoid personal injury do not perform any servicing unless you are qualified to do so Refer to all safety summaries prior to performing service Copyright Tektronix Inc rights reserved Tektronix products are covered by U S and foreign patents issued and pending Information in this publication supercedes that in all previously published material Specifications and price change privileges reserved Printed in the U S A Tektronix Inc Box 1000 Wilsonville OR 97070 1000 TEKTRONIX and TEK are registered trademarks of Tektronix Inc Tektronix warrants that the products that it manufactures and sells will be free from defects in materials and workmanship for a period of one 1 year from the date of shipment If a product proves defective during this warranty period Tektronix at its option either will repair the defective product without charge for parts and labor or will provide a replacement in exchange for the defective product In order to obtain service under this warranty Customer must notify Tektronix of the defect before the expiration of the warranty period and make suitable arrangements for the performance of service Cust
49. ace the carrying strap perform the following procedure 1 Insert the two standoff studs of the carrying strap through the battery cover and install the two retaining nuts 2 Install the battery cover Refer to Battery Cover on page 6 18 Turnlock Stud and Bushing To remove the turnlock stud and bushing perform the following procedure 1 Remove the battery cover Refer to Battery Cover on page 6 18 2 Gently pry up on the outside portion of the bushing as shown in Figure 6 8 3 Gently pull and rock the turnlock stud while holding the bushing Battery Cover Bushing Turnlock 1 Bushing gt e Figure 6 8 Removal and replacement of the turnlock stud 6 20 WFM 90 WFM 91 Service Manual Removal Replacement To replace the turnlock stud and bushing perform the following procedure 1 Press the turnlock stud into the bushing 2 install the turnlock stud and bushing into the battery cover press firmly on the turnlock stud head Be sure to keep the bushing head level with the battery cover while you press on the turnlock stud The bushing will snap into place when it is correctly installed 3 Install the battery cover Refer to Battery Cover on page 6 18 Battery Cushion Pad To remove the battery cushion pad perform the following procedure 1 Remove the battery cover Refer to Battery Cover on page 6 18 2 Toremove the cushion pad pry it up around the edges and pul
50. ad if you have replaced the Top board Refer to Keypad on page 6 13 Gently press on the bottom of the Top board to insert the Top board connector into the Bottom board connector Be sure that the circuit board shield is properly aligned Refer to Top Board Shield on page 6 14 Install the two retaining screws into the top of the Top board Install the top cover Refer to Top Cover on page 6 7 Keypad To remove the keypad perform the following procedure 1 2 3 Remove the top cover Refer to Cover on page 6 7 Remove the Top board Refer to Top Board on page 6 13 Gently pull the keypad from the Top board To replace the keypad perform the following procedure 1 2 Press the nubs the keypad through the holes in the board Use tweezers or needle nose pliers from the backside of the Top board to pull the nubs of the keypad through the Top board See Figure 6 4 WFM 90 and WFM 91 Service Manual 6 13 Removal Replacement 6 14 Pull nub through board with tweezers Top board Figure 6 4 Installing the keypad 3 Install the Top board Refer to Top Board on page 6 13 4 Install the top cover Refer to Top Cover on page 6 7 Top Board Shield To remove the Top board shield perform the following procedure 1 Remove the top cover Refer to Top Cover on page 6 7 2 Remove the two retaining screws from the top of the Top board 3 Slide the Top board shie
51. addresses of manufacturers of components listed in the mechanical parts list Abbreviations conform to American National Standards Institute ANST standard Y 1 1 1972 The part numbers for the standard and optional accessories available with this instrument are located at the end of the replaceable parts list WFM 90 and WFM 91 Service Manual Replaceable Parts List Manufacturers Cross Index Mfr Code 0DWW6 0GV90 0 01 01 2 14310 39951 13143 15915 80009 83285 93907 94222 1415 1416 2427 WFM 90 WFM 91 Service Manual Manufacturer MICRO POWER ELECTRONICS GLOBTEK INC STAUFFER SUPPLY CO LZR ELECTRONICS INC AULT INC AROW COMPONENTS amp FASTENERS INC FISCHER SPECIAL MFG CO LITTELFUSE TRACOR INC SUB OF TRACOR INC TEKTRONIX INC STEWARD MFG CO CAMCAR DIV OF TEXTRON INC SOUTHCO INC CABOT SAFETY CORP SHARP CORP A D ELECTRONICS INC Address 7973 SW CIRRUS DRIVE BLDG 22 186 VETERANS DRIVE 810 SE SHERMAN 8051 CESSNA AVENUE 7300 BOONE AVE NORTH BROOKLINE PARK AROW COMPONENTS amp FASTENERS INC 31012 HUNTWOOD AVE 111 INDUSTRIAL RD PO BOX 76500 800 E NORTHWEST HWY 14150 SW KARL BRAUN DR PO BOX 500 1200 E 36TH ST PO BOX 510 ATTN ALICIA SANFORD 516 18TH AVE 210 BRINTON LAKE RD 7911 ZIONSVILLE RD 22 22 NAGAIKE CHO ABENO KU 10421 BURNHAM DRIVE NW BLDG 4 City State Zip Code BEAVERTON OR 97008 NORT
52. agtaims ELSE RENE UE 9 1 WFM 90 and WFM 91 Service Manual Table of Contents List of Figures Figure 2 1 Installing the viewing hood 2 2 Figure 2 2 Installing the desk 2 2 Figure 2 3 Instrument front panel 2 4 Figure 2 4 Instrument side panels 2 7 Figure 2 5 On screen readout messages 2 9 Figure 3 1 Simplified block diagram 3 3 Figure 4 1 3 dB marks on the vector graticule 4 12 Figure 5 1 NTSC graticule showing the vector gain adjustment 5 9 Figure 6 1 Removing the top cover 6 7 Figure 6 2 Installing the LCD display cable 6 9 Figure 6 3 Installing the LCD display 6 11 Figure 6 4 Installing the keypad 6 14 Figure 6 5 Installing the Top board shield 6 15 Figure 6 6 Installing the Bottom board 6 17 Figure 6 7 Installing the battery cover 6 19 Figure 6 8 Removal and replacement of the turnlock stud 6 20 Figure 6 9 Removing the NiCad battery pack 6 22 Figure 6 10 Installed polarity of alkaline batteries 6 23 Figure 6 11 Battery contact installation alignment 6 25
53. arts list Cross Index Mfr Code Number to Manufacturer Abbreviations Instrument Accessories 8 2 Table 8 1 Replaceable parts list column descriptions Column Name Fig amp Index Number Description Items in this column are referenced to the exploded view item numbers Tektronix P art Number Serial No Effective Serial No Discont d Use this part number when ordering replacement parts from Tektronix This column indicates the instrument serial number at which the part was first effective No entry indicates the part is good for all serial numbers This column indicates the instrument serial number at which the part was discontinued No entry indicates the partis good for all serial numbers Qty This column indicates the quantity of parts used Name amp Description Mfr Code An item name is separated from the description by a colon Because of space limitations an item name may sometimes appear incomplete Use the U S Federal Catalog handbook H6 1 for further item name identification This column indicates the code of the actual manufacturer of the part Code to name and address cross reference is located after this page Mfr Part Number This column indicates the actual manufacturer s or vender s part number The Mfg Code Number to Manufacturer Cross Index for the mechanical parts list is located immediately after this page The cross index provides codes names and
54. bad menus in the picture display 6 48 Figure 6 30 Flowchart for dim or blotchy display 6 49 Figure 6 31 Flowchart for bad displays except Picture mode 6 49 Figure 6 32 Circuit board connector and pin locations 6 50 Figure 8 1 Exploded view 8 4 Figure 9 1 Interconnect diagram 9 1 WFM 90 and WFM 91 Service Manual Table of Contents List of Tables Table 1 1 Vertical deflection system 1 6 Table 1 2 DC restoration 1 7 Table 1 3 Audio mode 1 7 Table 1 4 Horizontal deflection system 1 8 Table 1 5 Vector mode 1 8 Table 1 6 Synchronization 1 10 Table 1 7 Physical characteristics 1 10 Table 1 8 Environmental characteristics 1 10 Table 1 9 Powersource 1 11 Table 1 10 Safety EMI 1 12 Table 2 1 Front panel and menu default settings 2 10 Table 4 1 Summary verification procedure 4 1 Table 4 2 Equipment required for performance verification 4 2 Table 5 1 Summary adjustment 5 1 Table 5 2 Equipment required for performance verification
55. ck of the Bottom board To replace the Backlight board perform the following procedure 1 Be sure that the Backlight board shield is in place if you have replaced the Backlight board Install the Backlight board into the back of the Bottom board Align the Backlight and Input boards with the slots in the bottom cover and gently slide the boards into the bottom cover WFM 90 and WFM 91 Service Manual 6 17 Removal Replacement ccm WD Install the Top board Refer to Top Board on page 6 13 Install the LCD display module Refer to LCD Display on page 6 9 Install the top cover Refer to Top Cover on page 6 7 Install the battery cover Refer to Battery Cover on page 6 18 Input Board Assembly remove the Input board perform the following procedure 1 2 5 6 Remove the top cover Refer to Cover on page 6 7 Remove the battery cover Refer to Battery Cover on page 6 18 Lift on the Bottom board while you press on the battery connector in the battery compartment Gently pull the Input board assembly from the back of the Bottom board Unscrew the retaining nuts from the three BNC connectors on the rear panel Pull the rear panel cover off of the BNC connectors To replace the Input board perform the following procedure 1 B 0 49 H Install the rear panel cover over the BNC connectors on the Input board Install the retaining nuts onto the three BNC connectors on the rear panel In
56. ck stud and bushing 6 20 Battery cushion pad 6 21 NiCad battery pack 6 21 Alkaline batteries 6 22 Bottom cover 6 23 Battery power connector 6 24 Battery contacts 6 24 Tumlock stud receptacle 6 26 Bottom cover electrical shield 6 21 Battery orientation marker and battery cushion pad 6 27 AC adapter EMI suppressor 6 29 WFM 90 and WFM 91 Service Manual Removal Replacement Top Cover Assembly The top cover assembly contains replaceable subparts Procedures for removing the subparts are included below Top Cover To remove the top cover assembly perform the following procedure 1 Remove the six retaining screws using the Torx tip screwdriver See Figure 6 1 Bes Remove Torx screws 6 Figure 6 1 Removing the top cover WFM 90 and WFM 91 Service Manual 6 7 Removal Replacement 6 8 LCD Display Assembly A 2 Gently lift the top cover off of the bottom cover NOTE When you are disassembling the WFM 90 or WFM 91 do not let dust accumulate inside of the top cover Set the top cover face up on your work surface or cover it with a lint free cloth to prevent dust from accumulating on the inside surface of the cover To replace the top cover assembly perform the following procedure 1 Make sure that the battery and backlight wires are positioned so that they will not be pinched between the top and bottom covers 2 Align the top cover over the bottom cover so that the k
57. d of the latest information on improvements to the product as well as the latest new options to the product Tektronix warrants this product for one year from date of purchase The warranty appears after the title page and copyright page in this manual Tektronix technicians provide warranty service at most Tektronix service locations worldwide Your Tektronix product catalog lists all service locations worldwide WFM 90 and WFM 91 Service Manual XV Introduction xvi Repair or Calibration Service Self Service The following services may be purchased to tailor repair and or calibration of your WFM90 or WFM91 Handheld Waveform Vector Picture and Audio Monitor to fit your requirements Option M2 When you order option M2 you receive a five year warranty and remedial service agreement Option M8 When you order option 8 you receive four free calibration and performance tests At Depot Service Tektronix offers several standard priced adjustment calibra tion and repair services W A single repair and or adjustment m Calibrations using equipment and procedures that meet the traceability standards specific to the local area m Annual maintenance agreements that provide for either calibration and repair or calibration only of the instrument Of these services the annual maintenance agreement offers a particularly cost effective approach to service for many owners of the WFM90 or WFM91 Handheld Waveform Vector
58. d remove installed batteries from the monitor before starting disassembly See CAUTION To prevent damage to the instrument disconnect the power adapter Batteries on page 6 21 To prevent damage to the instrument be sure to follow the preparation instruc tions on page 6 2 Tools Required Use the tools in Table 6 1 to disassemble the instrument to its individual modules Some of these tools are required only for removal of specific instru ment components Table 6 1 Tools required for module removal Name Description Torx screwdriver handle Accepts Torx driver bits T 10 Torx tip Torx driver bit for T 10 size screw heads 1 point Philips tip 9 16 hexagonal driver Deep socket 1 4 hexagonal driver Flat blade screwdriver Tweezers or needle nose pliers Cleaners See Cleaning on page 6 3 Soldering iron 40 W Solder 2 flux content solder WFM 90 and WFM 91 Service Manual 6 5 Removal Replacement Procedures 6 6 Table 6 2 lists the removal and replacement procedures in this section and their starting page numbers Table 6 2 Removal and replacement procedure list Replaceable part Page number Top cover 6 7 LCD display lens 6 8 LCD display 6 9 LCD display padding 6 11 Backlight 6 12 Top board 6 13 Keypad 6 13 Top board shield 6 14 Bottom board 6 16 Backlight board 6 17 Input board assembly 6 18 Battery cover 6 18 Carrying strap 6 19 Tumlo
59. dB WIP location Bottom right Alarms Off Safe Action Off Safe Title Off Vertical shift Off Backlight time out Disabled Instrument time out Disabled WFM 90 and WFM 91 Service Manual Theory of Operation SES Theory of Operation This section contains a module level description of the instrument circuitry Block Diagram Description The following description is based on the block diagram in Figure 3 1 Input Board The signal input and output connectors are located on the Input board There are receivers for the three inputs a switch for the video signal reference and a variable gain circuit for the audio input The video input signal has a DC voltage feedback clamp from the Bottom board The video output signal from the Bottom board is routed through the Input board The audio variable gain is controlled by the microprocessor serial bus which is routed to the Input board from the Top board through the Bottom board Top Board The Top board contains the microprocessor circuitry the rasterizer and graphics generator the subcarrier oscillator and the timing generator Microprocessor The microprocessor takes input from the front panel keypad to control the operation of the instrument through the serial bus parallel bus and dedicated control lines Rasterizer and Graphics The rasterizer and graphics block produces all internally generated video including waveforms graticules and menus The rasterizer uses the
60. de The standard SPG2 and SPG12 modules will not check lock to changes in sync amplitude cw lock to changes in burst amplitude and frequency lock to burst offset frequency changes The signal generator can be ordered with one or both options AA and AB The TSG3 TSG13 are Modulated Staircase Generators with variable APL The 565 and TSG15 are Pulse and Bar Generators with modulated pulse and field square wave signals Requires a Tektronix TM 500 Series or TM 5000 Series Power Module Mainfram WEM 90 and WFM 91 Service Manual e 4 3 Performance Verification Performance Verification Procedures 4 4 Conventions Prerequisites Perform the performance verification procedures to ensure that the instrument is operating properly and is meeting the performance requirements listed in the characteristic tables of the Specifications section Throughout these procedures the following conventions apply Each verification procedure uses the following format Title of verification procedure Specification requirement s the procedure is verifying Verification procedure When you are instructed to use a front panel control or to select a specific menu item of the WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor the name of the control or menu item appears in boldface type NOTE Do not make changes to the front panel settings or controls that are not called out in the procedures Each procedure wi
61. e two backlight connectors 3 Grasp the sides of the LCD display to lift it up off of the locating feet and disconnect the ribbon cable from the back of the display module NOTE The cable connecting the display module to the Bottom board is a zero insertion force ribbon cable To remove the cable from the connector housing pull out the connector latch and then pull the ribbon cable out of the connector See Figure 6 2 Contacts Open slide latch connector to install cable Close latch connector Figure 6 2 Installing the LCD display cable WFM 90 and WFM 91 Service Manual 6 9 Removal Replacement 6 10 NOTE Some early instruments used cushion pads instead of locating feet to hold the display module in position If your instrument has cushion pads replace the pads at this time with locating feet Contact your local Tektronix representative to order the necessary parts To replace the LCD display module perform the following procedure CAUTION To avoid miscalibrating your display module do not touch the display adjustments on the backside of the display module These adjustments are set by the manufacturer and should not be adjusted 1 If you have replaced the display module with a new one attach the cushion padding around the display module Refer to Display Padding on page 6 11 2 Connect the ribbon cable from the Bottom board into the back of the dis
62. e video and external reference inputs each have a rear panel switch providing the choice of an internal 75 Q signal termination or an unterminated high imped ance input The audio input connector is a standard 3 pin XLR connector WFM 90 and WFM 91 Service Manual Specifications The video output will drive a remote monitor or video switcher The audio signal is output through a mini headphone stereo jack that outputs the mono input signal to both stereo channels The audio volume is fixed for each reference level The larger the displayed signal the louder the volume Waveform Display Mode The Waveform display mode provides a voltage versus time display of the video signal with three standard sweep rates 5 Us divi sion 2H 10 Us division and 2F two field Each line rate sweep can be magnified X10 to the following sweep rates Mag 0 5 uis division and 2H Mag 1 Us division The 2F sweep is magnified by approximately X20 Vertical gain is fixed at X1 or 5 or is variable from 45 to 155 amplitude The gain setting tracks between the Waveform and Vector display modes The signal filters are Flat no filter and Luminance low pass filter The Line Select mode enables the selection of a single line of video for display Vector Display Mode The Vector display mode presents an XY plot of the demodulated chrominance phase and amplitude portion of the video signal The vector angle represents chrominance phase and the
63. ecifications as listed in the Official ournal of the European Communities EN 50081 1 Emissions EN 55022 Class B Radiated and Conducted Emissions EN 50082 1 Immunity IEC 801 2 Electrostatic Discharge Immunity IEC 801 3 RF Electromagnetic Field Immunity IEC 801 4 Electrical Fast Transient Burst Immunity 1 12 WFM 90 and WFM 91 Service Manual SS eee Operating Information SSS 54 Operating Information Installation Mechanical Installation This section contains the following information Mechanical and electrical installation instructions m Operating instructions that relate to the service of this instrument Before installing the WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor refer to the Environmental Characteristic requirements located in Table 1 8 on page 1 10 of the Specifications section qualification testing was performed with the factory shipped cabinet installed To guarantee compliance with specifications only operate the instrument in its cabinet Follow these instructions when you are mechanically installing this instrument Unpacking Save the shipping carton and packing materials including antistatic bag in the event it becomes necessary to ship the instrument to a Tektronix Service Center for service or repair Refer to Repackaging Instructions on page 6 4 for instructions on packaging the instrument for shipment Cabin
64. en in all sweep modes Description REF NTSC 3 579545 MHz PAL 4 43361875 MHz REQ Upper 3 dB Point Foc 500 kHz 100 kHz Lower 3 dB Point 500 kHz 100 kHz REF V type display as selected by front panel button When pushed the V axis is inverted ata 1 2 line rate to produce a single vector display REF 1 25 REF Measured with color bar signal REF Typically 2 596 REF Typically 0 5 WFM 90 and WFM 91 Service Manual Specifications Table 1 5 Vector mode Cont Category Display Differential Phase Display Differential Gain Subcarrier Regenerator P ull In Range Subcarrier Regenerator Pull In Time Subcarrier Regenerator Phase Shift w Subcarrier Frequency Change Subcarrier Regenerator P hase Shift w Amplitude Change Subcarrier Regenerator P hase Shift w Gain Control Subcarrier Regenerator P hase Contro Subcarrier Regenerator Burst itter ith ith Burst ith Variable Range WFM 90 and WFM 91 Service Manual Description REQ REQ REQ REQ REF 1 REF Measured with 140 IRE 1 V linearity signal 5 step 10 step or Ramp with 40 IRE 300 mV of subcarrier REF 1 REF Measured with 140 IRE 1 V linearity signal 5 step 10 step or Ramp with 40 IRE 300 mV of subcarrier NTSC 50 Hz of Fsc PAL 10 Hz of Fsc REF Subcarrier Regenerator free runs in absence of appropriate signal Reference can be burst of either displayed
65. ents to the instrument Repackaging instructions to prepare the instrument for shipment If the instrument does not function properly troubleshooting and corrective measures should be taken immediately to prevent additional problems NOTE Contact your local Tektronix representative for information on where to return your instrument if it requires repair during the warranty period Preparation Please read and follow these preparation instructions before attempting to perform any maintenance or service to the instrument Servicing Prerequisites Make sure of the following before beginning any instrument service The maintenance or service of this instrument must be performed by qualified service personnel only Read the Service Safety Summary located at the beginning of this manual before attempting to perform any maintenance or service to the instrument Read the Operating Information section of this manual before attempting to perform any maintenance or service to the instrument WFM 90 and WFM 91 Service Manual 6 1 Maintenance Electrostatic Damage Prevention AN 6 2 This instrument contains electrical components that are susceptible to damage from electrostatic discharge Static voltages of 1 to 30 kV are common in unprotected environments CAUTION Static discharge can damage any semiconductor component in this instrument Observe the following precautions to avoid static damage m Minimize hand
66. eplace the Backlight in the Display module Remove the AC adapter and then remove the Display module and the Backlight board Reattach the AC adapter and leave the VIDEO IN and VIDEO OUT cables attached Power up the instrument Is there 400 VAC as measured on the oscilloscope No Yes Replace the Backlight in the Display module Check Backlight power supply inputs 20 1 Ground 12 VDC Vin 1 Vpp ripple 5 VDC Backlight Enable 355006 1 25 175 VDC as the brightness is changed using the CONFIGURE menu Figure 6 17 Flowchart for no display WFM 90 and WFM 91 Service Manual Check the Display drive signals Probe 16 from the back of the Bottom board 16 9 1 VDC to 3 VDC as VIEW is adjusted in the CONFIGURE menu 16 10 DSYNC 0 to 600 mV compsync J16 14 SEL_EXVID 5 VDC in PIX mode and 0 VDC in Waveform mode Select PIX Mode No Menu Use 100 flat field test signal J16 6 B 2 VDC blanking level 2 5 V peak video J 16 7 G 2 VDC blanking level 2 5 V peak video 16 8 R 2 VDC blanking level 2 5 V peak video Select WFM Mode MENU Use 75 color bar signal J 16 2 B 0 to 1 3 V sies ecard J 16 4 R 0 to 1 3 V Check for bad or misaligned Display module interface cable If cable is ok replace the Display module Are all of these signals correct If the DISP BRT signal is bad replace the Bottom board If the
67. ervice Manual m NiCad battery pack m Desk stand m Viewing hood m Carrying Case for this instrument and a Pathfinder TSG 90 Series Signal Generator 7 2 WFM 90 WFM 91 Service Manual us ud Replaceable Parts EU I 4 Replaceable Parts List This section contains a list of the replaceable modules for this instrument Use this list to identify and order replacement parts Parts Ordering Information Replacement parts are available through your local Tektronix Inc Field Office or representative Changes to Tektronix instruments are sometimes made to accommodate improved components as they become available and to give you the benefit of the latest circuit improvements Therefore when ordering parts it is important to include the following information in your order m Part number m Instrument type or model number Instrument serial number Instrument modification number if applicable If you order a part that has been replaced with a different or improved part your local Tektronix Inc Field Office or representative will contact you concerning any change in part number Module Servicing Refer to Service Offerings on page xv for information on the service offerings that Tektronix Inc provides for this instrument WFM 90 and WFM 91 Service Manual 8 1 Replaceable Parts List Using the Replaceable Parts List Table 8 1 describes each column in the replaceable p
68. ery or DC powered When the instrument power times out the ON button must be pressed to turn the instrument back on The instrument power shutdown is only functional when the instrument is battery powered WFM 90 and WFM 91 Service Manual Operating Information Calibration Mode The Calibration mode allows you to adjust the instrument to factory specifications if necessary The Calibration mode is entered by pressing and holding the CONFIG button for a few seconds The instrument adjustments are performed entirely from the front panel with the use of specified input signals The instructions for readjusting the instrument to specifications are located in the Adjustment Procedures section listed in the Adjustment Procedures section or your instrument may not meet the T CAUTION Do not attempt to adjust the instrument without using the instructions published specifications On screen Readout This instrument uses on screen messages to alert you to certain monitoring conditions Figure 2 5 shows the readout messages and their locations 1 2 3 GAIN EXTREF 10uS DIV 6 L MISSING SYNC 1 1 4 LOW BAT lt _ 5 Figure 2 5 On screen readout messages Readout Description Listed below are the corresponding descriptions of the on screen readout messages m The GAIN UNCAL message appears in the Waveform Vector and Waveform in Picture display modes when the Variable Gain mode is turned on m The EXT REF
69. et The WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor is shipped installed in a cabinet There are not any optional cabinets available Viewing Hood The optional viewing hood allows you to readily view the instrument display in well lighted situations The hood is attached to the instrument by first applying the supplied Velcro strips to the sides of the instrument and then pressing the flaps of the viewing hood onto the strips as shown in Figure 2 1 WFM 90 and WFM 91 Service Manual 2 1 Operating Information Figure 2 1 Installing the viewing hood Desk Stand The optional desk stand provides the user with a stable means to hold the instrument upright on a flat surface The prongs of the stand are inserted into the holes in the back of the instrument as illustrated in Figure 2 2 Figure 2 2 Installing the desk stand 2 2 WFM 90 and WFM 91 Service Manual Operating Information Electrical Installation Follow these instructions when physically installing this instrument Power Source This instrument is designed to operate from either six C cell batteries alkaline or rechargeable NiCad or from an AC adapter wall unit producing 12 VDC power source other than the supplied AC adapter ensure that the DC source is a negative ground 11 V to 18 V system with a negative center lead The DC source must provide 12 W of power CAUTION avoid possible damage to the instrument circuitry whe
70. eypad buttons will slide through the top cover keypad holes 3 Gently lower the top cover onto the bottom cover A slight shaking motion of the top cover may be necessary to help the keypad buttons slide through the top cover holes 4 Install the six retaining screws using the Torx tip screwdriver LCD Display Lens To remove the LCD display lens perform the following procedure 1 Remove the top cover Refer to Top Cover on page 6 7 2 Press firmly on the LCD display lens from the front of the top cover until it comes loose from the top cover 3 Clean any remaining glue residue from the top cover Refer to Cleaning on page 6 3 To replace the LCD display lens perform the following procedure 1 Remove the protective cover from the cushion on the new LCD display lens 2 Align the LCD display lens with the depression in the backside of the top cover and press the lens into place 3 Install the top cover Refer to Top Cover on page 6 7 The LCD display assembly contains replaceable subparts Procedures for removing the subparts are included below CAUTION To avoid damaging the LCD display do not touch the face of the display because it is hard to clean and is easily scratched WFM 90 and WFM 91 Service Manual Removal Replacement LCD Display To remove the LCD display assembly perform the following procedure 1 Remove the top cover Refer to Top Cover on page 6 7 2 Disconnect the wires from th
71. f 12 major divisions 23 Select CAL MENU and then select SAVE 24 Select 2H SWEEP from the Operating menu 25 Select MAG REG from the Calibration menu and then select CAL 26 Select POS and then use the Arrow Buttons to position the falling edge of sync to the center graticule tick mark 27 Select MAG ON and then select MAG REG 28 Adjust the Arrow Buttons to reposition the falling edge of sync to the center graticule tick mark 29 Select MAG OFF 30 Select CAL MENU and then select SAVE Perform the following steps to adjust the vertical gain and X5 gain registration Replace the signal on the VIDEO IN connector with the output from the VAC Do not terminate the input 2 Set the VAC for a 999 9 mV output with all of the buttons out except LUM and NTSC PAL button for the WFM 91 3 Select X1 GAIN from the Calibration menu and then select CAL o Adjust the Arrow Buttons for a display amplitude of exactly 140 IRE 1000 mV PAL Select CAL MENU and then select SAVE Set the VAC for a 199 9 mV output Select X5 GAIN from the Operating menu Select X5 GAIN from the Calibration menu and then select CAL 9 6 on Adjust the Arrow Buttons for a display amplitude of exactly 140 IRE 1000 mV PAL 10 Select CAL MENU and then select SAVE 11 Replace the signal on the VIDEO IN connector with a 7596 color bar signal from the television signal generator using a 75 Q in line terminator 12 Select X
72. fore proceeding with the following procedure 1 Disconnect the AC adapter from the instrument Remove any installed batteries See Batteries on page 6 21 Remove the top cover See Top Cover on page 6 7 Bop Remove the bottom cover See Bottom Cover on page 6 23 CAUTION To avoid breaking the circuit boards do not tighten the circuit board vise too tightly 5 Secure the instrument circuit boards in the circuit board vise 6 35 Troubleshooting Procedures 6 Connect a 7596 color bar test signal to the VIDEO IN connector and connect the VIDEO OUT connector to the picture monitor 7 Locate your fault symptom in Table 6 5 and go to the flowchart indicated to isolate the faulty module Table 6 5 Fault symptom table Symptom Flowchart No display after pressing the front panel ON button page 6 37 Graticule is ok butthe Waveform display is distorted or not visible page 6 38 Graticule is ok butthere is no Vector display page 6 39 Graticule is ok butthe Audio display is distorted or not visible page 6 40 No display in the Picture display mode page 6 41 Bad graticule and menu but Picture display mode ok page 6 42 Display all white page 6 43 Waveform display mode sweep not triggered page 6 44 Vector display unlocked page 6 45 Vector display jitter page 6 46 Distorted vectors in Vector display page 6 46 Control problem page 6 47 Menus horizontally unlocked in Picture display mode page 6 48 Dim or blotch
73. gnal on the VIDEO IN connector with a pulse and bar signal using a 75 Q in line terminator 13 Check by adjusting the Vertical Position controls that the white bar and sync tip portions of the signal can be adjusted to the graticule baseline 14 Select VAR GAIN OFF from the Configuration menu 15 Select X1 GAIN from the Operating menu Overscan This procedure verifies the following requirement x 2 variation in baseline of 100 IRE 700 mV PAL 12 5T 20T PAL modulated pulse as it is positioned over the middle 80 of the screen 1 Check that the amplitude of the sine wave at the bottom of the mod pulse varies less than 296 while using the Vertical Position controls to position the signal over the middle 80 of the graticule 2 Remove the pulse and bar signal from the VIDEO IN connector 4 8 WFM 90 and WFM 91 Service Manual Performance Verification Input and DC Restorer This procedure verifies the following requirement Frequency Response X1 Gain Response Flat filter selected 50 KHz to 6 MHz within 2 of response at 50 kHz X5 Gain Response Flat filter selected 50 kHz to 6 MHz within 5 of response at 50 kHz Attenuation of 60 Hz 50 Hz PAL on Input Signal SLOW mode x 20 FAST mode 90 1 2 10 11 12 13 14 15 16 Select EXT REF from the Configuration menu Connect the 50 precision cable from the output of the leveled sine wave generator to the dual input coupler using a 50
74. he following steps to prepare the instrument to be adjusted 1 Plug the AC power adapter into the WFM 90 or WEM 91 Handheld Waveform Vector Picture and Audio Monitor and then plug the adapter into the AC power source 2 Setthe input termination switches to the HIZ position on the WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor 3 Connect a 75 color bar signal from the television signal generator to the VIDEO IN connector using a 75 Q in line terminator 4 Turnon the instrument 5 Press the CONFIG button Select PRESETS and then select DEFAULT Perform the following steps to adjust the raster VCO 1 Select RAST VCO from the Calibration menu 2 Select CAL and then select AUTO 3 Wait until the CANCEL message disappears from the screen 4 Select CAL MENU and then select SAVE from the menu WFM 90 and WFM 91 Service Manual Adjustment Procedures Sweep Timing and Perform the following steps to adjust the sweep timing and horizontal mag Horizontal Mag registration Registration 1 Replace the signal on the VIDEO IN connector with the output from the function generator sure to use a 50 to 75 Q minimum loss attenuator and a precision 1 50 cable if the generator specifies a 50 Q output Set the function generator for a 200 kHz sine wave output NOTE Verify the generator frequencies used in these steps by checking them on the frequency counter m
75. ice Manual 6 45 Troubleshooting Procedures Use this procedure when there is Vector display jitter This problem can be caused by either the Top or Bottom boards and can only be determined by replacing these boards one ata time Figure 6 26 Flowchart for vector display jitter Use this procedure when the vectors are distorted in the Vector display mode Perform the following steps in the Adjustment Procedures using the CALIBRATION menu Vector Quadrature P hase Vector Gain and X5 Gain Phase Does this remedy the Problem solved problem Check the IFsc and QFsc signals J 9 is on the Top Board J 9 42 400 mVpp filtered square wave 19 43 300 mVpp filtered square wave Are the IFsc and QFsc signals ok Yes Replace the Bottom board Replace the Top board Figure 6 27 Flowchart for distorted vectors 6 46 WFM 90 WFM 91 Service Manual Troubleshooting Procedures Use this procedure when there is an instrument control problem Do menu selections change as the front panel buttons are pressed and does the graticule appear ok Replace the Bottom board Do some Remove the Keypad from Top board and clean front panel keys work the contacts located under the carbon buttons and some Replace the Keypad do not Other control problems include The instrument does not respond to front panel key presses after being turned on All display
76. ideo In 5 Video In Ext Ref Video RGB from Ref Rasterizer and Graphics Audio Var Audio 4 Gain i a i Headphone 1 1 DC In 11 18 VDC Power Supply and Battery Charger NTSC or PAL 8 VDC 5 VDC Vector Decoder Self contained subcarrier Vectorscope Including shifter P O Top Board Rasterizer and Graphics Instrument Control DSync RGB Sel Vid RGB LCD Display regenerator Control DAC 16 analog Outputs Sync Timin kartor Separator 9 S ubcarrier Oscillator HT PRENNE Timing and Backlight Brightness Power and View Supply Adjust Board Backlight Brightness Figure 3 1 Simplified block diagram WEM 90 and WFM 91 Service Manual 3 3 Theory of Operation 3 4 WFM 90 and WFM 91 Service Manual dE Performance Verification P D Performance Verification This section contains the following information m Summary verification procedure m List of equipment required to perform the procedures W Performance verification procedures Summary Verification The summary verification is listed in Table 4 1 and is intended for those who are familiar with the complete performance verification procedures Procedure titles and page numbers provide a cross reference to
77. ining screws on the backlight assembly with the Philips screwdriver Do not remove the center screw Gently pull the backlight out of the LCD display module To replace the backlight perform the following procedure 1 Install the backlight assembly into the side of the LCD display module CAUTION avoid breaking the backlight do not force the backlight assembly into the LCD display module Install the two retaining screws into the backlight assembly Install the display padding onto the side of the LCD display module Refer to LCD Display Padding on page 6 11 A new display pad is supplied with the replacement backlight assembly Install the LCD display module Refer to LCD Display on page 6 9 Install the top cover Refer to Top Cover on page 6 7 WFM 90 and WFM 91 Service Manual Removal Replacement Top Board Assembly Top board assembly contains replaceable subparts Procedures for removing the subparts are included below Top Board To remove the Top board perform the following procedure 1 Remove the top cover Refer to Top Cover on page 6 7 Remove the two retaining screws from the top of the Top board Gently pull on the bottom of Top board to separate it from the Bottom board If you are replacing the Top board remove the keypad from the Top board Refer to Keypad on page 6 13 To replace the Top board perform the following procedure 1 Install the keyp
78. ins See Figure 6 16 Battery connector J umper wires 3 gt Test resistor Figure 6 16 Testing the battery charging circuit WFM 90 SN 011363 and above WFM 91 SN B010471 and above WFM 90 and WFM 91 Service Manual 6 33 Troubleshooting Procedures A NOTE If the jumper wires will not stay securely attached to the battery connector pins you will need to remove the instrument bottom case to obtain access to the battery connector pins on the Bottom board Refer to Bottom Cover on page 6 23 4 Attach the voltmeter across the test resistor in Figure 6 16 5 Connect the AC adapter to the WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor 6 Check for a voltage reading of 2 VDC on the voltmeter with the WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor turned on and a reading of 8 to 9 VDC with the instrument turned off The voltage will slowly rise when the instrument is turned off 7 Ifthe voltage reading in the previous step was correct replace the batteries If the voltage reading was incorrect replace the Bottom board WARNING To prevent electric shock and high voltage arcing do not operate the Backlight power supply with the LCD module removed High voltages in excess of 1 kV can be present on the Backlight power supply leads when operated open circuit If the LCD module is removed always remove the Backlight board before powering up the instrume
79. interior of the instrument allow the interior to thoroughly dry before reassembling and applying power to the instrument Display Screen The display screen is susceptible to smudging from dirt and grease The recommended cleaning agent is petroleum ether which is available from the vendor listed below JT Baker Inc Phillipsburg NJ 08865 USA 908 859 2151 WFM 90 and WFM 91 Service Manual 6 3 Maintenance Visual Inspection Performance Verification and Readjustments After cleaning carefully check the instrument for defective connections damaged parts and improperly seated transistors or integrated circuits The remedy for most visible defects is obvious however if heat damaged parts are discovered determine the cause of overheating before replacing the damaged part Periodic checks of the transistors and integrated circuits are not recommended The best measure of performance is the actual operation of the component in the circuit Instrument performance should be checked after each 2000 hours of operation or every 12 months This will help to ensure maximum performance and assist in locating defects that may not be apparent during regular operation Performance Verification and Adjustment Procedures are included in this manual After Repair Adjustments It is recommended that you perform the Adjustment Procedures starting on page 5 1 whenever you have removed the Top or Bottom cover during the service of this inst
80. ion of the Arrow Buttons is dependent on the current state of the instrument For the Waveform and Audio display modes they control signal positioning For the Vector display mode they control vector phase with the A and y buttons providing fine adjustment and the and p buttons providing coarse adjustment The Arrow Buttons retain their default function for the reduced display when the Waveform in Picture display mode is selected When the Configuration menu is displayed the and y buttons operate the menu category selection while the lt and buttons retain their default function for the current display mode Instrument Reset Extraordinary conditions may cause the instrument controls to become locked or to respond erratically To reset the instrument first press the ON button to turn off the power then press the ON button again while holding down the WIP and LINE SEL buttons The instrument should return to normal operation with the keypad controls and menu selections assigned to the factory set defaults If this reset does not return the instrument to normal operation refer to the Troubleshooting Procedures section of this manual The instrument side panels are illustrated in Figure 2 4 Video Input and Output Connectors The VIDEO IN and REF IN connectors are passive BNC inputs unterminated and 75 Q compensated for a video signal Each input has a rear panel switch to provide an internal 75 2 signal termination The VID
81. ix part number 011 0103 02 Frequency counter Range 10 Hz to 10 MHz Tektronix DC 503A Universal Counter Accuracy 0 00196 Video amplitude calibrator Signal Adjustable square wave 0 0 mVpp to Tektronix part number 067 0916 002 VAC 999 9 mVpp Resolution 0 1 mV Accuracy 0 0596 Frequency Approximately 270 Hz Peak to peak detector Input Signal Range 0 25 Vpp to 1 0 Vpp Tektron Flatness 0 2 50 kHz to 10 MHz peak to peak detector head Tektronix part Input Impedance 75 O number 015 0413 00 2 15 Q terminator Two required feed through type Tektron 15 Q coaxial cable Two cables required male to male BNC Tektron connectors 50 coaxial cable 196 precision male to male BNC connectors Te ktron ix part number 012 0159 00 42 inch ix part number 012 0482 00 36 inch Audio cable XLR female to XLR male Switchcraft part number 5 50 Q to 75 minimum loss Impedance 50 O to 75 Tolerance 0 5 dB attenuator Frequency 100 MHz X10 attenuator Dual input coupler Matched BNC cable T for making phase comparisons between two inputs Matched length of the two arms within 0 1 inch BNC female to BNC female Te connector ktron ktron ktron ktron ix part number 011 0057 00 ix part number 011 0061 00 ix part number 067 0525 02 ix part number 103 0028 00 1 The1410 Series generators with standard SPG and TSG modules can be used but not all checks and adjustments be ma
82. l it off of the battery cover 3 If necessary clean the surface of the cushion pad to remove any remaining glue residue See Cleaning on page 6 3 To replace the battery cushion pad perform the following procedure 1 Peel off the protective covering of the adhesive surface of the cushion pad 2 Position the cushion pad in place above the battery cover before you press it onto the battery cover Rub your fingers over the pad once it is positioned on the battery cover to make sure the pad is securely in place 3 Install the battery cover Refer to Battery Cover on page 6 18 Batteries There are two procedures for replacing the batteries The first is for the optional NiCad battery pack and second is for alkaline batteries NiCad Battery Pack To remove the NiCad battery pack perform the following procedure 1 Remove the battery cover Refer to Battery Cover on page 6 18 2 Grasp the batteries close to the wire leads Use your thumb to press in on the top portion of the battery connector tab and then pull gently upwards See Figure 6 9 WFM 90 and WFM 91 Service Manual 6 21 Removal and Replacement Grasp wire Figure 6 9 Removing the NiCad battery pack To replace the NiCad battery pack perform the following procedure 1 Press the battery connector onto the jumper in the battery compartment Be sure the battery connector tab snaps onto the jumper housing to prevent a loss of battery power 2 Install the
83. ld out from under the Top board To replace the Top board shield perform the following procedure 1 Ifyouare replacing the Top board shield bend the tab on the shield as shown in Figure 6 5 WFM 90 and WFM 91 Service Manual Removal Replacement The shield tab goes on top of the board post Lift up the board to slip the shield underneath the top board and dd circuit Shield C Fold tab Figure 6 5 Installing the Top board shield 2 Slide the shield under the Top board and align the cutouts in the shield with the mounting posts of the Top board NOTE Be sure to properly align the tab of the Top board shield so that the tab is under the Top board and that the Top board retaining screw goes through the tab Failure to do this will result in noisy display graphics See Figure 6 5 3 Install the two retaining screws into the top of the Top board 4 Install the top cover Refer to Top Cover on page 6 7 WFM 90 and WFM 91 Service Manual 6 15 Removal and Replacement 6 16 Bottom Board To remove the Bottom board perform the following procedure 1 Ue 7 Remove the top cover Refer to Top Cover on page 6 7 Remove the LCD display module Refer to LCD Display on page 6 9 Remove the Top board Refer to Top Board on page 6 13 Remove the battery cover Refer to Battery Cover on page 6 18 Lift on the Bottom board while you press on the ba
84. ling of static sensitive components m Transport and store static sensitive components or assemblies in their original containers on a metal rail or on conductive foam Label any package that contains static sensitive assemblies or components m Discharge the static voltage from your body by wearing a wrist strap while handling these components Servicing static sensitive assemblies or components should only be performed at a static free workstation by qualified personnel m Nothing capable of generating or holding a static charge should be allowed on the workstation surface m Keep the component leads shorted together whenever possible Pick up components by the body never by the leads m Do not slide the components over any surface W Avoid handling components in areas that have a floor or work surface covering capable of generating a static charge m Use a soldering iron that is connected to earth ground m Use only special antistatic suction type or wick type desoldering tools NOTE A 2 RMA flux content solder is recommended for making repairs in this instrument Cleaning of rosin residue is not recommended Most cleaning solvents tend to reactivate the rosin and spread it under components where it may cause corrosion under humid conditions The rosin residue if left alone does not exhibit these corrosive properties WFM 90 and WFM 91 Service Manual Maintenance Inspection and Cleaning Preventive maintena
85. ll require you to set the instrument to certain default settings before verifying the procedure requirement If you make changes to these settings other than those called out in the procedure you may obtain invalid results The verification procedures are written in a format that assumes you are performing the procedures in sequential order from the beginning If you are unsure about equipment hookups or instrument settings for a specific procedure you will need to review the previous procedures to verify the hookups and settings required for the current procedure The tests in this section comprise a valid confirmation of instrument performance when the following requirements are met m Test equipment used to verify performance requirements must be calibrated and working within the limits specified in Table 4 2 on page 4 2 The WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor must have last been adjusted at an ambient temperature range of 20 C to 30 C and must have been operating for a warm up period of at least 20 minutes WFM 90 and WFM 91 Service Manual Performance Verification Preliminary Setup Perform the following steps before beginning the verification procedures 1 Plug the AC power adapter into the instrument and then plug the adapter into the AC power source Connect the multiburst signal from the television signal generator through a 75 Q in line terminator dual input c
86. m the Calibration menu and then select CAL Select PHASE then use the Arrow Buttons to position the burst vector exactly on the 180 graticule line Select X5 GAIN and then select X5 PHASE Adjust the Arrow Buttons so that the burst vector lands exactly on the 180 graticule line Select CAL MENU and then select SAVE Adjustment Procedures 5 10 Audio Gain Perform the following steps to adjust the audio gain 1 2 Connect the output from the audio generator to the AUDIO IN connector Set the audio generator for a 1 KHz tone output with an amplitude of 48 0 dBu Select Signal On from the audio generator Select the AUDIO display mode on the WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor Select 8 dBu from the Operating menu Select AUD GAIN from the Calibration menu and then select CAL Adjust the Arrow Buttons so that the signal display lands exactly on the 8 dBu graticule lines Select CAL MENU and then select SAVE WFM 90 and WFM 91 Service Manual fain Maintenance Maintenance This section contains instructions for servicing the WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor that include the following information Preparation procedures to observe before performing maintenance Procedures for inspecting and cleaning the instrument Module removal and replacement instructions Troubleshooting procedures After repair adjustm
87. minal Refer to Manual Insulated Certifications and Refer to the specifications section for a listing of certifications and compliances Compliances that apply to this product WFM 90 amp WFM 91 Service Manual General Safety Summary X WFM 90 amp WFM 91 Service Manual 7 amp Service Safety Summary Only qualified personnel should perform service procedures Read this Service Safety Summary and the General Safety Summary before performing any service procedures Do Not Service Alone Do not perform internal service or adjustments of this product unless another person capable of rendering first aid and resuscitation is present Disconnect Power To avoid electric shock disconnect the power by means of the ac adapter or if provided the power switch Use Care When Servicing With Power On Dangerous voltages or currents may exist in this product Disconnect power remove battery if applicable and disconnect test leads before removing protective panels soldering or replacing components To avoid electric shock do not touch exposed connections WFM 90 amp WFM 91 Service Manual xi Service Safety Summary Xii WFM 90 amp WFM 91 Service Manual Preface This manual provides instructions for servicing the WFM 90 and WFM 91 Handheld Waveform Vector Picture and Audio Monitors This manual describes features and specifications that are common to all generator m
88. n 2 while varying the burst amplitude from nominal to 6 dB 1 2 to 2X amplitude using the television signal generator burst amplitude control Return the burst amplitude to nominal on the television signal generator Select VAR GAIN ON from the Configuration menu Check that the vector phase changes less than 1 while varying the vector burst amplitude from 1 2 to 1 5 times nominal amplitude using the variable gain control Select VAR GAIN OFF from the Configuration menu Remove the signal input from the VIDEO IN connector Chrominance Bandwidth This procedure verifies the following requirement Chrominance Bandwidth Upper 3 dB Point 500 kHz 100 kHz Lower 3 dB Point 500 kHz 100 kHz 1 Connect the precision 50 cable to the output of the leveled sine wave generator Connect the other end of the cable to the 50 Q to 75 Q minimum loss attenuator and then connect the attenuator to the VIDEO IN connector Select EXT REF from the Configuration menu WFM 90 and WFM 91 Service Manual 4 11 Performance Verification 4 12 3 Set the leveled sine wave generator frequency to 3 58 MHz 4 43 MHz PAL and adjust the amplitude control so that the circle overlays the graticule compass rose Decrease the frequency on the leveled sine wave generator until the edge of the circle display reaches the 3 dB 70 gaps on the vertical graticule axis See Figure 4 1 3 dB Points Compass
89. n Company date or purchase order number Address Repair Protection 1 2 or 3 years City State Postal code Calibration Services 1 2 3 4 or 5 years Country Instrument model and serial number Phone Instrument purchase date Table of Contents General Safety Summary vii Service Safety Summary xi Preface eeu UNE EE s nA MUS xiii Introduction a e re t RR rS AERE KR Ra p e Xv SerVICe SLTAle BY oce e det ee Rh RR Service Offer gs iv seo ER e e s Before You Begin RR ER Er xvii Specifications Product Description 1 1 Charactenstics Tables e n 1 5 Operating Information Histallati n tee a he eee ert dev ot Maw oka yt EN 2 1 Operating Information 2 4 Theory of Operation Block Diagram Description 3 1 Performance Verification Summary Verification 4 1 Equipment 4 2 Performance Verification 4 4 Adjustment Procedures Summary 1 1 5 1 Equipme
90. n how to install and remove the batteries Operational Jumpers and Installed Options This instrument does not have any internal operational jumpers or installed options All instrument configurations are available through the on screen menus Operating Environment Refer to Table 1 8 on page 1 10 for the environmental limits of this instrument WFM 90 and WFM 91 Service Manual 2 3 Operating Information Operating Information This section will acquaint you with the basic principles of operating this instrument so that you can service it Detailed operating instructions are located in the user manual Front Panel Controls The instrument front panel is illustrated Figure 2 3 TEK WFM90 Figure 2 3 Instrument front panel 2 4 WFM 90 and WFM 91 Service Manual Operating Information Power Switch Press the ON button to toggle the instrument power on and off The current instrument keypad and menu selections are saved when the instrument is turned off using this button NOTE The instrument configuration is not saved if the power source is removed before the instrument is turned off with this button Display Mode Selection Use the following front panel buttons to access the different display modes Press the WFM button to enter the Waveform display mode Press the VECT button to enter the Vector display mode Press the AUDIO button to enter the Audio display mode P
91. n using a DC Fuse This instrument does not have an external power fuse There are two fuses located internally on the Bottom board See page 6 34 of the Maintenance section for instructions on how to check and replace the power supply fuses Battery Operation The rechargeable NiCad batteries are automatically recharged when the AC adapter is plugged into the instrument whether the instrument power is on or off The battery charge time is approximately 6 5 hours when the instrument is off and 20 hours when the instrument is on The instrument shifts into a safe trickle charge mode which can run indefinitely when the NiCad batteries are fully charged See Table 1 9 on page 1 11 for information regarding the length of time the instrument will operate on batteries The message Low Bat is displayed on screen when the remaining battery power cannot guarantee reliable instrument operation The length of time the instrument will continue to operate after this message is displayed is dependent on the current operating mode of the instrument and the type of batteries installed Use the rechargeable NiCad battery pack in full charge and discharge cycles to optimize the battery life and capacity Fully discharge the battery pack before recharging and then charge the battery pack until it is fully charged A new battery pack will take a few charge and discharge cycles to reach full capacity Refer to Batteries on page 6 21 for the instructions o
92. nce consists of cleaning visual inspection performance checking and if needed readjustment The preventive maintenance schedule established for the instrument should be based on the environment in which it is operated and the amount of use Under average conditions scheduled preventive maintenance should be performed every 2000 hours of operation General Care Protect this instrument from adverse weather conditions The instrument is not waterproof Do not expose the LCD display to direct sunlight for long periods of time CAUTION To avoid damage to this instrument do not expose it to sprays liquids or solvents Cleaning The instrument should be cleaned often enough to prevent dust or dirt from accumulating Dirt acts as a thermal insulating blanket that prevents effective heat dissipation and can provide high resistance electrical leakage paths between conductors or components in a humid environment Clean the exterior of the instrument by removing dust with a lint free cloth Use care to avoid scratching the clear plastic display lens A small soft bristled brush is useful to remove dust from around the selector buttons and connectors For further cleaning use a soft cloth or paper towel dampened with water You can use a 75 isopropyl alcohol solution for more efficient cleaning i CAUTION To avoid damage to the surface of this instrument do not use abrasive or chemical cleaning agents If you must clean the
93. nector pins See Figure 6 15 Battery connector A Test resistor 2 umper wires 3 iy External power supply Test resistor 1 Figure 6 15 Testing the battery charging circuit WFM 90 SN 011362 and below WFM 91 SN B010470 and below WFM 90 and WFM 91 Service Manual Troubleshooting Procedures NOTE If the jumper wires will not stay securely attached to the battery connector pins you will need to remove the instrument bottom case to obtain access to the battery connector pins on the Bottom board Refer to Bottom Cover on page 6 23 4 Attach the voltmeter across test resistor 1 in Figure 6 15 5 Connect the AC adapter to the WFM 90 or WEM 91 Handheld Waveform Vector Picture and Audio Monitor 6 Check for a voltage reading of 8 to 9 VDC on the voltmeter with the instrument turned on or off 7 Ifthe voltage reading in the previous step was correct replace the batteries If the voltage reading was incorrect replace the Bottom board WFM 90 SN B011363 Use the following procedure to determine if the battery charger circuit is and Above operating properly WFM 91 SN B010471 1 Remove the AC adapter from the WFM 90 or WFM 91 Handheld Wave and Above form Vector Picture and Audio Monitor 2 Remove the battery cover and any installed batteries from the instrument See Batteries on page 6 21 3 Use three jumper wires to connect a 30 3 W resistor to the battery connector p
94. nput control until the green LED is on Note the digital multimeter readout level or the oscilloscope dc level Set the sine wave generator frequency to 3 58 MHz 4 43 MHz PAL Adjust the amplitude of the sine wave generator so that the digital multime ter readout or oscilloscope level matches that noted in step 9 Select X1 FREQ from the Calibration menu and then select CAL Adjust the Arrow Buttons for a display amplitude of exactly 100 IRE 700 mV PAL Select CAL MENU and then select SAVE Select X5 GAIN from the Operating menu WFM 90 and WFM 91 Service Manual 5 7 Adjustment Procedures 16 17 18 19 20 21 22 23 24 Set the leveled sine wave generator frequency to 50 KHz and adjust the generator amplitude for exactly 100 IRE 700 mV PAL of display Adjust the peak to peak detector Plus amplifier and input control fully counterclockwise Note the digital multimeter readout level or the oscilloscope dc level Set the sine wave generator frequency to 3 58 MHz 4 43 MHz PAL Adjust the amplitude of the sine wave generator so that the digital multime ter readout or oscilloscope level matches that noted in step 18 Select X5 FREQ from the Calibration menu and then select CAL Adjust the Arrow Buttons for a display amplitude of exactly 100 IRE 700 mV PAL Select CAL MENU and then select SAVE Select X1 GAIN from the Operating menu and INT REF from the Configuration menu Vec
95. nt 5 2 Adjustment Procedures 5 3 Maintenance Preparation i e cepe PP LULA A ei ae E 6 1 Inspection and Cleaning 6 3 After Repair Adjustments 6 4 Repackaging Instructions 6 4 Removal and Replacement 6 5 Tools Required re het beet ad eps 6 5 ee IE LI ENS 6 6 Troubleshooting Procedures 6 31 Equipment Required erae c Ea EROR HI bg dia 6 31 Battery Fault Analysi8 ute ELLE DU LEO ERN ON DERE 6 32 Low Voltage Power Supply 6 35 WFM 90 WFM 91 Service Manual i Table of Contents Options Replaceable Parts List Diagrams Fault Symptom Table 6 35 Troubleshooting Flowcharts 6 36 Connector DIagrani ciu eun ASBESTOS INE YN 6 50 CEPR SERE RE Up RP eb ete ed 7 1 ACCES SOTIES Te pee ER ES 7 2 Parts Ordering Information 8 1 Using the Replaceable Parts List 8 2 Di
96. nt Solder only this side Black wire Receptacle prongs Turnlock stud receptacle Figure 6 12 Battery power wire and turnlock stud receptacle installation 4 Install the bottom cover Refer to Bottom Cover on page 6 23 Turnlock Stud Receptacle To remove the turnlock stud receptacle perform the following procedure 1 Remove the bottom cover Refer to Bottom Cover on page 6 23 2 Depress the retaining fingers on the turnlock stud receptacle and push the receptacle through the bottom cover See Figure 6 12 6 26 WFM 90 and WFM 91 Service Manual Removal Replacement To replace the turnlock stud receptacle perform the following procedure 1 Push the turnlock stud receptacle through the bottom cover Be sure the retaining fingers snap into position See Figure 6 12 2 Install the bottom cover Refer to Bottom Cover on page 6 23 Bottom Cover Electrical Shield Remove the electrical shield by performing the following procedure 1 Remove the bottom cover Refer to Bottom Cover on page 6 23 2 Pry up the electrical shield on the inside of the bottom cover around the edges and peel it off of the bottom cover 3 If necessary clean the surface of the bottom cover to remove any remaining glue residue To replace the electrical shield perform the following procedure 1 Peel off the protective covering of the adhesive surface of the electrical shield 2 Position the electrical
97. nt Select INT REF using the CONFIGURE menu Check for vertical and horizontal sync pulses 9 is on Top Board 19 18 TTL level V rate sync locked to the input signal 9 19 level H rate sync locked to the input signal Check the REF IN signal ps J 14 is on Bottom Board pulses J 14 9 1 2 Vpp 1 3 VDC ok blanking level Replace the Top board Replace the Input board Is the REF IN signal ok Yes Replace the Bottom board Figure 6 24 Flowchart for untriggered waveform display WFM 90 and WFM 91 Service Manual Troubleshooting Procedures Use this procedure when the Vector display is unlocked Remove the Display module and Backlight board Connectthe AC Adapter and power up the instrument Select INT REF using the CONFIGURE menu Is the Waveform display triggered Go to Figure 6 24 Check the Subcarrier Regenerator Oscillator SRO control voltage J 9 is on the Top board J 9 12 approximately 1 VDC Check the IF sc signal J 9 is on the Top board 9 43 2300 mV filtered square wave Is the contro SRO signal Yes This problem can be caused by either the Top or Bottom boards and can only be determined by replacing these boards one ata time Is the IFsc signal ok Replace the Bottom board No Replace the Top board Figure 6 25 Flowchart for unlocked vector display WFM 90 and WFM 91 Serv
98. nt for test Low Voltage Power Supply 6 34 Use the following procedure to check that the low voltage power supplies are operating properly before proceeding to Fault Symptom Table 1 Disconnect the AC adapter from the WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor Remove any installed batteries See Batteries on page 6 21 Remove the top cover See Top Cover on page 6 7 Connect the AC adapter and turn on the instrument am Check the supply voltages listed in Table 6 4 WFM 90 and WFM 91 Service Manual Troubleshooting Procedures Fault Symptom Table AN WFM 90 and WFM 91 Service Manual Table 6 4 Low voltage power supplies Supply Test Point Output Ripple gy 20 mv 8 V J9 pin 14 30 mV 6 Ifthe low voltage power supplies are operating properly proceed to Fault Symptom Table 7 If any of the voltages are out of specification check the two fuses on the Bottom board CAUTION Do not use a soldering iron larger than 18 W or you may damage the circuit board and the surrounding circuitry 8 Ifa fuse is bad remove the AC adapter and replace the fuse before you retest the low voltage power supplies 9 If both of the fuses are ok replace the Bottom board NOTE Be sure to remove all modules one at a time to isolate the Bottom board in cases where a supply might be excessively loaded Be sure to check the low voltage power supplies be
99. oard Yes Check the audio deflection signals J 9 is on the back of Top board J9 121Vpp 2VDC 9 3 2 1 V to 43 8 V ramp with a 35 ms period Are the audio deflection signals ok Replace the Bottom board Replace the Top board Figure 6 20 Flowchart for bad audio display 6 40 WFM 90 and WFM 91 Service Manual Troubleshooting Procedures Use this procedure when there is no display in the Picture display mode Is there a display in any other operating mode except WIP Go to Figure 6 17 Remove the Display module and the Backlight board Power up the instrument Connect a 100 flat field test signal to the VIDEO INPUT Select the Picture display mode Check the Display drive signals Probe 16 from the back of the Bottom board VDC 2 5 V peak video VDC 2 5 V peak video VDC 2 5 V peak video Display drive signals ok Replace the Bottom board Check the SEL EXVIDEO signal Probe J 16 from the back of the Bottom board 16 14 2 45 VDC in PIX mode Is the SEL_EXVIDEO signal ok Replace the Top board Yes Replace the Display module Figure 6 21 Flowchart for no picture display WFM 90 and WFM 91 Service Manual 6 41 Troubleshooting Procedures Use this procedure when the graticule and menu are bad but the PIX mode is ok moderate to severe vertical flutter Perform the Raster VCO adjustment if pos
100. ode The Waveform in Picture WIP display mode provides a 1 4 screen sized window over the Picture display for any one of the Waveform Vector or Audio displays The WIP window can be positioned to any one of the four corners of the display The Arrow Buttons retain their default function for the display mode in the WIP window Line Select Mode The Line Select mode enables you to select any line of video for viewing in either the Waveform or Vector display modes The desired line can be selected from either all video fields or from alternating fields With two field sweep selected in the Waveform display mode the selected line is highlighted in the field display Time out Mode When the Time out mode is enabled power is turned off to the display backlight and or the instrument when the front panel has not been in use for a menu selected length of time Amplitude Alarm Mode The Amplitude Alarm mode provides automatic signal level checking in the Waveform and Audio display modes In the Waveform display mode the portion of the waveform exceeding the 100 IRE 1 0 V PAL graticule line is highlighted In the Audio display mode the portion of the waveform exceeding the selected reference level is highlighted Preset Menu The Preset menu allows you to store the current instrument front panel and menu settings for future use In addition there is a menu selection that sets the front panel and menu settings back to the factory set defaults Refer
101. odules These include system configuration and the common control interface About This Manual This manual is composed of the following sections Related Manuals Specifications lists the electrical and environmental specifications and provides a general product description Operating Information describes installation and front panel operation of the instrument Theory of Operation contains a module level description based on block diagrams of the instrument circuitry Performance Verification provides procedures for verifying instrument performance Adjustment Procedures provides procedures for adjusting the instrument to meet performance levels listed in Specifications Maintenance contains instructions for cleaning the instrument procedures for removal and replacement of instrument modules and troubleshooting procedures Options lists all of the options that you might find on your instrument Replaceable Electrical Parts points you to Replaceable Mechanical Parts for the list of replaceable electrical parts and assemblies Diagrams contains the instrument interconnect diagram Replaceable Mechanical Parts lists the part numbers of the replaceable electrical and mechanical parts and assemblies The WFM 90 and WFM 91 Handheld Waveform Vector Picture and Audio Monitor User Manual Tektronix part number 070 8968 X X describes in detail how to operate the instrument WFM 90 and WFM 91 Service Manual xiii Preface
102. omer shall be responsible for packaging and shipping the defective product to the service center designated by Tektronix with shipping charges prepaid Tektronix shall pay for the return of the product to Customer if the shipment is to a location within the country in which the Tektronix service center is located Customer shall be responsible for paying all shipping charges duties taxes and any other charges for products returned to any other locations This warranty shall not apply to any defect failure or damage caused by improper use or improper or inadequate maintenance and care Tektronix shall not be obligated to furnish service under this warranty a to repair damage resulting from attempts by personnel other than Tektronix representatives to install repair or service the product b to repair damage resulting from improper use or connection to incompatible equipment c to repair any damage or malfunction caused by the use of non Tektronix supplies or d to service a product that has been modified or integrated with other products when the effect of such modification or integration increases the time or difficulty of servicing the product THIS WARRANTY IS GIVEN BY TEKTRONIX IN LIEU OF ANY OTHER WARRANTIES EXPRESS OR IMPLIED TEKTRONIX AND ITS VENDORS DISCLAIM ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE TEKTRONIX RESPONSIBILITY REPAIR OR REPLACE DEFECTIVE PRODUCTS IS THE SOLE AND EXCLUSIVE REMEDY PR
103. oupler to the VIDEO IN and REF IN connectors on the WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor Set the input termination switches to the HIZ position Turn on the WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor Enter the Configure menu Select PRESETS and then select DEFAULT NOTE Be sure you have warmed up the instrument for at least 20 minutes before you perform any of the verification procedures Sync Separation This procedure verifies the following requirement Signal synchronization will occur with input signals of composite video or black burst with sync amplitudes of 40 IRE 300 mV PAL 6 dB for internal reference and sync amplitudes of between 143 mV and 4 V for external reference 1 so qd ww 9 9 d Enter the Configuration menu and select the INPUT category Check for a stable display while switching between INT and EXT REF Remove the terminator from the dual input coupler Check for a stable display while switching between INT and EXT REF Add three 75 terminators to the dual input coupler Check for a stable display while switching between INT and EXT REF Select INT REF from the Configuration menu INPUT category Remove the dual input coupler from the instrument WFM 90 and WFM 91 Service Manual 4 5 Performance Verification Sweep Timing and Integral This procedure verifies the following requirement Linearity Sweep Timing Accurac
104. pin on the Replace the Bottom board Replace the Input board WFM 90 and WFM 91 Service Manual Troubleshooting Procedures Use this procedure when the graticule is ok but there is no Vector display Remove the Display module and Backlight board Power up the instrument and select DEFAULT PRESETS from the CONFIGURE tor display mode menu Select Vec Check the VIDEO IN signal J 14 is on the Bottom board 1142 21 3 Vpp 0 VDC Goto Figure 6 18 Check the vector deflection signals B Y R Y J 9 is on the back of the Top board 1 1 3 Vpp 2 5 VDC 3 20 6 Vpp 2 5 VDC Are the vector deflection signals ok Replace the Bottom board Yes Replace the Top board Figure 6 19 Flowchart for no vector display WFM 90 and WFM 91 Service Manual 6 39 Troubleshooting Procedures Use this procedure when the graticule is ok butthe Audio display is distorted or not visible Remove the Display module and the Backlight board Power up the instrument and select DEFAULT PRESETs from the CONFIGURE menu Selectthe Audio display mode Attach an audio input signal from 0 to 8 dbu Check the AUDIO IN signal J 15 is on the Bottom board J 15 4 Check for a gain of X1 above input signal level The Audio Amplifier gain is always X1 in 48 dbu The signal level should change as different reference dbu levels are selected from Replace the Input b
105. play module NOTE The cable connecting the display module to the Bottom board is a zero insertion force ribbon cable To install the cable into the connector pull out the connector latch and then push the ribbon cable into the connector housing When the cable rests against the back of the connector press in the connector latch to lock the cable in place See Figure 6 2 3 If you are replacing the ribbon cable set the LCD display just above its resting position on the locating feet Use your finger to crease the ribbon cable so that when the LCD display is set down on the locating feet the ribbon cable does not raise the LCD display up off of the locating feet 4 Setthe LCD display module onto the four locating feet The locating feet fit into small holes in each of the four corners on the back of the LCD display See Figure 6 3 5 Connect the backlight wires to the connectors on the side of the display module 6 If you have replaced the display module with a new one carefully remove the protective plastic cover from the face of the LCD display by prying up the corner of the cover and pulling it off of the display 7 If necessary clean the front of the LCD display Refer to Cleaning on page 6 3 8 Install the top cover Refer to Top Cover on page 6 7 WFM 90 and WFM 91 Service Manual Removal Replacement Level the pad flush with display case S NA
106. required male to male BNC Tektronix part number 012 0159 00 42 inch connectors Circuit board vise Test resistor Two 30 0 W Tektronix part number 308 0142 00 Test resistor 10 kQ 2 W Tektronix part number 305 0103 00 J umper wires Three 8 inch 20 AWG Tektronix 5282 12 V power supply WFM 90 and WFM 91 Service Manual 6 31 Troubleshooting Procedures Battery Fault Analysis WFM 90 SN B011362 and Below WFM 91 SN B010470 and Below 6 32 Use this procedure to troubleshoot battery or battery charging problems when the instrument functions properly when powered by the AC adapter If there are no battery problems or if the instrument does not function properly with the AC adapter go to Low Voltage Power Supply on page 6 35 Use the following procedure to determine if the battery charger circuit is operating properly NOTE The battery charging circuit in the WFM 90 SN B011362 and below and the WFM 91 SN B010470 and below will not charge a completely discharged battery The battery must have at least 4 V charge across the battery connector before the charging circuit will operate 1 Remove the AC adapter from the WFM 90 WFM 91 Handheld Wave form Vector Picture and Audio Monitor 2 Remove the battery cover and any installed batteries from the instrument See Batteries on page 6 21 3 Use three jumper wires to connect two 30 3 W resistors and an external 12 VDC power supply to the battery con
107. ress the PIX button to enter the Picture display mode Press the WIP button to enter the Waveform in Picture display mode The previously selected display mode other than Picture is shown in a 1 4 screen sized window that overlays the Picture display Menu Control Use the following front panel buttons to enter the different menus Press the MENU button to toggle the Operating menu on and off The Operating menu contains monitoring selections which are specifically related to the currently selected display mode Operating menu selections include signal gain and filtering audio reference levels and safe action and title outlines Press the CONFIG button to toggle the Configuration menu on and off The Configuration menu contains selections which control overall instrument monitoring operation Configuration menu contents include signal and display controls such as brightness and variable gain Special modes for monitoring signal amplitude and managing the battery power consumption are enabled in this menu Press the LINE SEL button to toggle the Line Select mode on and off and to display the Line Select menu The four unlabeled buttons directly below the display are referred to as the Bezel Buttons These buttons are used to make menu selections and are only enabled while menus are displayed on screen WFM 90 and WFM 91 Service Manual 2 5 Operating Information Side panel Connectors and Switches 2 6 Arrow Buttons The funct
108. ries Properly Do not attempt to recharge alkaline batteries NiCad batteries are automatically recharged in this instrument Replace the NiCad battery pack if the batteries do not recharge within the recommended time or if the operating time from a full charge seems significant ly shortened This product contains a Nickel Cadmium NiCd battery which must be recycled or disposed of properly For the location of a local battery recycler in the U S or Canada please contact RBRC 800 BATTERY Rechargeable Battery Recycling Corp 800 227 7379 P O Box 141870 WWW rbrc com Gainesville Florida 32614 WFM 90 amp WFM 91 Service Manual General Safety Summary Symbols and Terms Terms this Manual These terms may appear in this manual WARNING Warning statements identify conditions or practices that could result in injury or loss of life CAUTION Caution statements identify conditions or practices that could result in damage to this product or other property Terms on the Product These terms may appear on the product DANGER indicates an injury hazard immediately accessible as you read the marking WARNING indicates an injury hazard not immediately accessible as you read the marking CAUTION indicates a hazard to property including the product Symbols on the Product The following symbols may appear on the product AN m DANGER Protective Ground ATTENTION Double High Voltage Earth Ter
109. rom the Operating menu Check for one cycle per division 1 minor division over the center ten graticule divisions and also at both ends of the magnified sweep using the horizontal position control ignoring the first and last cycle Select MAG OFF from the Operating menu WFM 90 and WFM 91 Service Manual Performance Verification Vertical Gain and Vertical This procedure verifies the following requirement Magnifier Registration Nr Volt Full Scale 1 V input displayed within 1 of 140 IRE 1 00 V PAL X5 Gain Gain accuracy within 5 with 1 V input signal X5 Gain Registration lt 1 major division of vertical shift from baseline between unmagnified and magnified signal 1 Setthe multiburst generator controls to Composite and Multiburst 2 Position the signal baseline to the graticule baseline and then select X5 GAIN from the Operating menu 3 Check that the signal baseline is within 1 major division of the graticule baseline 4 Select X1 GAIN from the Operating menu 5 Remove the signal and terminator from the VIDEO IN connector 6 Connect the output of the VAC to the VIDEO IN connector Do not terminate the input 7 Setthe VAC for a 999 9 mV output with all of the buttons out except for LUM and NTSC PAL button for the WFM 91 8 Check for a display amplitude of 140 IRE 1 4 IRE 1000 mV 10 mV PAL 9 Setthe VAC fora 199 9 mV output 10 Select X5 GAIN from the Operating menu 11
110. rument Repackaging Instructions 6 4 Use the following instructions to prepare your instrument for shipment to Tektronix Inc Service Center 1 Attach a tag to the instrument showing the owner complete address and phone number of someone at your firm who can be contacted the instrument serial number and a description of the required service 2 Package the instrument in the original packaging materials If the original packaging materials are not available follow these directions a Obtain a carton of corrugated cardboard having inside dimensions six or more inches greater than the dimensions of the instrument Use a shipping carton that has a test strength of at least 250 pounds 113 5 kg b Place the instrument in its carrying pouch or surround the instrument with a protective bag Pack dunnage or urethane foam between the instrument and the carton If using Styrofoam kernels overfill the box and compress the kernels by closing the lid There should be three inches of tightly packed cushion ing on all sides of the instrument 3 Sealthe carton with shipping tape industrial stapler or both WFM 90 and WFM 91 Service Manual Removal and Replacement This section contains the instructions on how you can remove and replace the customer replaceable modules and parts of the WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor an
111. sible in the Adjustment procedures Check the Raster VCO control signal J 9 is on the Top board 9 6 Approximately 10 mVDC Replace the Bottom board Yes Replace the Top board Figure 6 22 Flowchart for bad graticules and menus 6 42 WFM 90 and WFM 91 Service Manual Troubleshooting Procedures Use this procedure when the display is all white Remove the Display module and Backlight board Connect the AC Adapter and power up the instrument Check the Display drive signals Probe 16 from the back of the Bottom board 16 9 1 to 3 VDC as VIEW is adjusted the CONFIGURE menu 16 10 DSYNC 0 to 0 6 V compsync J 16 14 SEL EXVID 5 VDC PIX mode 0 VDC Waveform mode Selectthe PIX Mode No Menu Use 100 flat field test signal 6 B 2 VDC blanking level 2 5 V peak video 7 G 2 VDC blanking level 2 5 V peak video 16 8 R 2 VDC Blanking 2 5 V peak video Select WFM Mode MENU Use 75 color bar signal 16 2 B 0 to 41 3 V 16 3 G Oto 41 3 V J16 4 R 0 to 1 3 V Replace the Bottom board Y Yes Replace the Display module Figure 6 23 Flowchart for all white display WFM 90 and WFM 91 Service Manual 6 43 Troubleshooting Procedures 6 44 Use this procedure when the Waveform display mode sweep is no triggered Remove the Display module and Backlight board Connect the AC Adapter and power up the instrume
112. ss 750 Video Out Differential Gain 50 APL Video Out Differential Phase 50 APL Table 1 2 DC restoration Category DC Restorer Clamp Time Frequency Response at 60 Hz 50 Hz PAL Table 1 3 Audio mode Category Reference Levels Measurement Accuracy Frequency Response Maximum Input Level Amplitude DC Input Impedance Audio Output Connector Maximum P ower Output WFM 90 and WFM 91 Service Manual Description REQ 15kQ REF With input switch in the HIZ position REF 240 dB from 50 kHz to 6 MHz with 75 Q termination REF 2 30 dB from 50 kHz to 6 MHz REF Within 1 with a 140 IRE 1 0 V PAL unit display REF Within 1 with a 140 IRE 1 0 V PAL unit display Description REF Back Porch REQ Attenuation of 60 Hz 50 Hz PAL on Input Signal Slow Mode lt 20 FastMode 290 REF Blanking Level Shift with 10 to 90 APL Change APL changes from 50 to either 10 or 90 will cause blanking level shift of 1 IRE unit 7 14 mV PAL or less REF Blanking Level Shift Due to Presence or Absence of Burst 1 IRE unit 7 14 mV or less shift from no color burst to presence of color burst Description REQ 10 dBu 0 dBu 4 dBu 8 dBu REF Nominal MIC Reference 50 dBu REQ 0 5 dB at 1 kHz REQ 0 5 dB from 50 Hz to 20 kHz REF 18 dBu gt 15 REF Mini stereo headphone jack REF 250 mW Specifications Table 1 4 Horizontal deflection system Category S
113. st signal to the REF IN connector Do not terminate the input Check that the display amplitude is 80 IRE 560 mV PAL Select FAST DC REST Check that the display amplitude is x 10 IRE 70 mV PAL Select INT REF and SLOW DC REST from the Configuration menu Remove all input signals from the WFM 90 or WFM 91 Handheld Wave form Vector Picture and Audio Monitor WFM 90 and WFM 91 Service Manual Performance Verification Vector Phase Stability This procedure verifies the following requirement Phase Shift with Subcarrier Frequency Change from Fsc to Fsc 50 Hz Fsc 10 Hz PAL 2 Phase Shift with Burst Amplitude Change from Nominal to 6 dB 2 Phase Shift with Variable Gain Control Varied from 3 dB to 6 dB 1 1 10 11 12 Connect a 75 color bar signal to the VIDEO IN connector Set the input switch to the 75 Q position Select VECTOR display mode on the WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor Use the Phase controls to position the burst vector on the 180 graticule line Check that when the television generator subcarrier frequency is changed 50 Hz 10 Hz PAL from nominal that the display locks and that the burst phase has changed 2 or less Return the subcarrier frequency to nominal on the television signal generator Replace the color bar signal on the VIDEO IN connector with a black burst signal Check that the vector phase changes less tha
114. stall the Input board assembly onto the back of the Bottom board Align the Backlight and Input boards with the slots in the bottom cover and gently slide the boards into the bottom cover Install the top cover Refer to Top Cover on page 6 7 Install the battery cover Refer to Battery Cover on page 6 18 Battery Cover Assembly The battery cover assembly contains replaceable subparts Procedures for removing the subparts are included below Battery Cover To remove the battery cover assembly perform the following procedure 1 2 6 18 Turn the turnlock stud 1 4 turn counterclockwise Pull outwards on the upper portion of the battery cover WFM 90 and WFM 91 Service Manual Removal Replacement To replace the battery cover assembly perform the following procedure 1 Place the lower lip of the battery cover into the instrument housing and press the top portion of the cover into the instrument See Figure 6 7 Battery Cover Figure 6 7 Installing the battery cover 2 Secure the battery cover by turning the turnlock stud 1 4 turn clockwise Carrying Strap To remove the carrying strap perform the following procedure 1 Remove the battery cover Refer to Battery Cover on page 6 18 2 Toremove the carrying strap remove the two retaining nuts on the inside of the battery cover and pull the carrying strap off of the cover WFM 90 and WFM 91 Service Manual 6 19 Removal and Replacement To repl
115. t diagram for the WFM 90 and WFM 91 Handheld Waveform Vector Picture and Audio Monitor M Input 2 Video In Board A3 Bottom Board yeu J14 jy Q Ref In 15 112 Video Out Audio In Testonly J15 2 12 A4 Backlight 25 Board 120 WI W2 W3 W4 A Backlight A5 LCD Displa NiCad Battery Pack T pee Module d 6 C Cell Batteries Figure 9 1 Interconnect diagram WFM 90 and WFM 91 Service Manual 9 1 Diagrams 9 2 WFM 90 and WFM 91 Service Manual
116. tch together See Figure 6 14 EMI suppressor Loop the cord through once Figure 6 14 Installing the suppressor WFM 90 and WFM 91 Service Manual 6 29 Removal Replacement 6 30 WFM 90 and WFM 91 Service Manual He Troubleshooting Procedures This section contains the following information starting on the listed pages m List of equipment required to perform the procedures this page m Battery fault analysis page 6 32 m Low voltage power supply page 6 34 m Fault symptom table page 6 35 m Troubleshooting flowcharts page 6 36 m Connector pin locator diagram page 6 50 Equipment Required The following equipment and accessory items are required to perform the Troubleshooting Procedures Minimum requirement specifications are followed by an example of equipment that meet these specifications Table 6 3 Equipment required for troubleshooting Equipment Description Minimum Requirements Equipment Example Television test signal generator 75 color bar and 100 flat field test signals for NTSC Tektronix TSG 100 the television standard of the monitor to be PAL Tektronix TSG 111 tested Audio generator Amplitude Range 10 dBu to 8 dBu Tektronix ASG 100 Audio Signal Generator Frequency 1 kHz to 50 kHz Oscilloscope 100 MHz Tektronix 1465B Picture monitor Composite video for the television standard of the monitor to be tested 75 coaxial cable Two cables
117. the performance verification procedures on the following pages Table 4 1 Summary verification procedure Procedure Procedure Requirement Page Preliminary setup Initial equipment connections and control settings 4 5 Sync separation Signal synchronization will occur with input signals of composite video or black burst with sync amplitudes of 40 IRE 300 mV PAL 6 dB for internal reference and sync amplitudes of between 143 mV and 4 V for external reference Sweep timing and integral linearity Sweep Timing Accuracy 5 us Div 1 Line 10 us Div 2 Line and 1 0 us Div 2 Line MAG 296 0 2 us Div 1 Line MAG 3 Integral Linearity 1 Vertical gain and vertical magnifier registration 1 Volt Full Scale 1 V input displayed within 1 of 140 IRE 1 00 V PAL X5 Gain Gain accuracy within 5 with 1 V input signal X5 Gain Registration 1 major division of vertical shift from baseline between unmagnified and magnified signal Variable gain range and vertical position range Variable Gain Range Input signals between 0 8 V and 2 V can be adjusted to 140 IRE 1 0 V display 160 mV and 400 mV for X5 Gain Vertical Position Range 1 V signal can be positioned so that peak white and sync tip can be placed at blanking level with the DC Restorer Clamp on regardless of gain setting Overscan x 2 variation in baseline of 100 IRE 700 mV PAL 12 5T 20T PAL 4 8 modulated pulse as it is positioned over the middle 80
118. ting specified for this product Do Not Operate in Wet Damp Conditions To avoid electric shock do not operate this product in wet or damp conditions Do Not Operate in an Explosive Atmosphere To avoid injury or fire hazard do not operate this product in an explosive atmosphere Do Not Operate With Suspected Failures If you suspect there is damage to this product have it inspected by qualified service personnel Observe All Ratings Observe and follow all ratings and markings on the product Consult the product manual s for further ratings information before making any connections to the product This product is intended to be connected to electrical devices with their common at ground potential Do not connect to elevated or floating common voltages WFM 90 amp WFM 91 Service Manual vii General Safety Summary viii Observe These Battery Precautions Battery Recycling For information on replacing and recharging batteries specific to this product refer to the detailed instructions provided in this manual Replace Batteries Properly Before replacing batteries turn the instrument off and disconnect the AC adapter Use only the size and type of batteries specified for this product Be sure to install the batteries in the proper polarity Use care not to short battery terminals together when replacing batteries When replacing alkaline batteries all batteries should be replaced at the same time Recharge Batte
119. tor Quadrature Phase Perform the following steps to adjust the vector quadrature phase 1 9 cS gg UU 5 8 Replace the signal on the VIDEO IN connector with a 75 color bar signal from the television signal generator using a 75 Q in line terminator Select VECTOR display mode WFM 91 ONLY Select ALT ON from the Configuration menu Select QUAD PH from the Calibration menu select CAL and then select RY OFFSET Adjust the Arrow Buttons for the best center dot overlay Select QUAD PH Adjust the Arrow Buttons for the best circle overlay Select CAL MENU and then select SAVE WFM 91 ONLY Select ALT OFF from the Configuration menu WFM 90 and WFM 91 Service Manual Adjustment Procedures Vector Gain and X5 Gain Perform the following steps to adjust the vector gain and X5 gain phase Phase WFM 90 ONLY Verify that the television signal generator has setup turned on Select VEC GAIN from the Calibration menu select CAL and then select TEST ON Adjust the A and y buttons so that the vector dots land in the center of the red and cyan graticule target boxes See Figure 5 1 Adjust buttons so that the vector dots land in the center of the yellow and blue graticule target boxes See Figure 5 1 Blue Blue Cyan Figure 5 1 NTSC graticule showing the vector gain adjustment WFM 90 and WFM 91 Service Manual Select CAL MENU and then select SAVE Select X5 PHASE fro
120. trument is left on in one display mode for an extended period of time This is typical for the LCD display device The retained image fades over time The fading can be accelerated by leaving the instrument turned off CAUTION To prevent image retention in the LCD display enable the backlight time out mode or turn the instrument off if the monitor will not be used for more than two hours Battery or AC Adapter Operation The instrument can be powered by six C cell batteries alkaline or NiCad or by an AC adapter wall unit with a negative center lead producing 12 VDC The rechargeable NiCad batteries are automatically recharged when the 12 VDC adapter is plugged into the instrument whether instrument power is on or off Alkaline batteries do not recharge The message Low Bat is displayed in the on screen readout when the batteries get critically low on power Menu Assisted Monitoring Operation The menus use a combination of on screen readout and multi use buttons in conjunction with the Arrow Buttons to control most of its monitoring functions Enter the menus by pressing one of the Menu Config or Line Sel buttons Menus are exited by pressing the entry button for the displayed menu or by entering another menu Video and Audio Input Output The instrument displays signals from the one channel of composite video input or from the one channel of audio input An external reference input allows the use of an external sync signal Th
121. ttery connector in the battery compartment Gently pull the Backlight board from the back of the Bottom board Gently pull the Input board assembly from the back of the Bottom board To replace the Bottom board perform the following procedure 1 2 Install the Input board into the back of the Bottom board Install the Backlight board into the back of the Bottom board Align the Backlight and Input boards with the slots in the bottom cover and gently slide the boards into the bottom cover See Figure 6 6 Install the Top board Refer to Top Board on page 6 13 Install the LCD display module Refer to LCD Display on page 6 9 Install the top cover Refer to Top Cover on page 6 7 Install the battery cover Refer to Battery Cover on page 6 18 WFM 90 and WFM 91 Service Manual Removal Replacement MX Backlight 22 Pd board Align the Backlight and Input boards into the slots ofthe bottom cover Input E assembly Figure 6 6 Installing the Bottom board Backlight Board remove the Backlight board perform the following procedure 1 2 3 4 Remove the top cover Refer to Top Cover on page 6 7 Remove the battery cover Refer to Battery Cover on page 6 18 Lift on the Bottom board while pressing on the battery connector in the battery compartment Gently pull the Backlight board from the ba
122. ubparts are included below Bottom Cover To remove the bottom cover perform the following procedure 1 Remove any installed batteries Refer to Batteries on page 6 21 2 Remove the six Torx screws from the bottom cover 3 Carefully remove the bottom cover and place it beside the top cover CAUTION To prevent damage to the battery power wires soldered to the bottom cover carefully remove the bottom cover WFM 90 and WFM 91 Service Manual 6 23 Removal Replacement 4 Liftthe Bottom board slightly out of the top cover so that you can pull the battery power wires from jumper J21 of the Bottom board See Figure 6 12 To replace the bottom cover perform the following procedure 1 Liftthe Bottom board slightly out of the top cover so that you can connect the battery power wires onto jumper J21 of the Bottom board 2 Carefully place the bottom cover onto the top cover CAUTION To prevent damage to the battery power or backlight wires carefully replace the bottom cover The bottom cover has slots in the molded plastic to hold both the Backlight board and Input board in place 3 Install the six Torx screws into the bottom cover 4 Install your removed batteries Refer to Batteries on page 6 21 Battery Power Connector To remove the battery power connector perform the following procedure 1 Remove the bottom cover Refer to Bottom Cover on page 6 23 2 Unsolder the battery connector wires from the
123. udio Flatness 2 5 1 Table 4 2 Equipment required for performance verification Minimum Requirements Color test signals for the television standard of the monitor to be tested color bar signal pulse and bar with 2T pulse 2T bar and modulated pulse field square wave signal and black burst signal Equipment Description Equipment Example NTSC Tektronix 14101 TV Test Signal Generator with Option AA and Option AB modified SPG2 and 7567 TSG3 and TSG5 PAL Tektronix 1411 TV Test Signal Generator with Option AA and Option AB modified SPG12 and 75617 T5G13 and TS G15 Tektronix SG 5032 Leveled Sine Wave Generator Television test signal generator Leveled sine wave generator Output Level Range 11 55 dBm 200 mV to 0 43 dBm 800 mV Frequency 50 kHz to 10 MHz Range 0 1 to 5 Vpp when loaded by 75 Q 10 Vpp when unloaded Frequency 50 kHz to 10 MHz Amplitude Range 10 dBu to 8 dBu Frequency 1 kHz to 50 kHz Range 0 VDC to gt 100 VDC Accuracy 0 1 Function generator Tektronix FG 5032 Function Generator Audio generator Tektronix ASG 100 Audio Signal Generator Voltmeter Tektronix DM 504A2 Digital Multimeter 4 2 WFM 90 and WFM 91 Service Manual Performance Verification Table 4 2 Equipment required for performance verification Cont Equipment Description Minimum Requirements Equipment Example ix part number 015 0408 00 includes
124. weep Sweep Repetition Rate 2LINE Sweep Repetition Rate 2FLD Sweep Repetition Rate 2FLD Sweep Magnification Sweep Magnifier R egistration Timing Accuracy Integral Linearity Horizontal Position Table 1 5 Vector mode Category Chrominance Processing Nominal Subcarrier Frequency Fsc Chrominance P rocessing Chrominance Bandwidth Chrominance P rocessing Mode Applicable to PAL operation only Display Vector Phase Accuracy Display Vector Gain Stability Display Quadrature P hasing 1 8 Description REQ Sweep will occur in all horizontal mode settings with or without synchroniza tion REF Sweep Length Two Line and Two Field sweep length is nominally 12 divisions REQ Equal to line rate of applied video or external sync REQ Equal to half line rate of applied video or external sync REF Displays 2 full fields including the field rate sync between them REF Approximately X20 REF Magnification occurs about the center of the screen REF All timing and linearity specifications exclude the first and last major divisions of the unmagnified display REQ 10 ws division 2LINE Within 2 REQ 5 usldivision 1LINE Within 296 REQ 1 ws division 2LINE MAG Within 296 REQ 0 5 us division 1LINE MAG Within 3 REQ Within 196 REF Measured between the 10 ws and 110 ws points on the 10 us division 2LINE sweep REF Any portion of a synchronized video sweep can be positioned on scre
125. working within the limits specified in Equipment Required on page 4 2 Reference Information Information that amplifies a performance requirement or is of special importance is indicated by REF There is no need to check these items to a specific tolerance Safety Standards The following safety standards apply to the WFM 90 or WFM 91 Handheld Waveform Vector Picture and Audio Monitor ANSI ISA S82 Safety Standard for Electrical and Electronic Test Measuring Controlling and Related Equipment CAN CSA C22 2 No 1010 1 92 Safety Requirements for Electrical Equipment for Measurement Control and Laboratory Use IEC1010 1 Safety Requirements for Electrical Equipment for Measurement Control and Laboratory Use 1990 UL3111 Standard for Electrical Measuring and Test Equipment WFM 90 and WFM 91 Service Manual 1 5 Specifications Table 1 1 Vertical deflection system Category Frequency Response Deflection Factor Transient Response Maximum Absolute Input Level 1 6 Description REQ REQ REQ REQ REQ REQ REQ REF Specifications apply for full screen height video input signal with Vari able Gain off Flat Filter 1 V Full Scale 50 kHz to MHz within 2 of response at 50 kHz FlatFilter X5 Gain 50 kHz to 6 MHz within 596 of response at 50 kHz REF Low Pass Filter gt 40 dB attenuation at 3 58 MHz NTSC or 4 43 MHz PAL REF Response at 15 kHz does not vary between Flat
126. y 5 us Div 1 Line 10 us Div 2 Line and 1 0 us Div 2 Line MAG 2 0 2 us Div 1 Line MAG 3 Integral Linearity 1 1 10 11 12 13 14 15 4 6 Connect the multiburst signal from the television signal generator to the VIDEO IN connector on the WFM 90 WFM 91 Handheld Waveform Vector Picture and Audio Monitor and to the input on the frequency counter using a T connector 75 Q cable and 75 Q in line terminator Set the multiburst generator controls to Low Continuous and Manual Set the output frequency to 100 kHz as read on the frequency counter Check for one cycle per division 1 minor division over the center ten graticule divisions Select 1H SWEEP from the Operating menu Set the multiburst generator frequency to 200 kHz Check for one cycle per division 1 minor division over the center ten graticule divisions Adjust the multiburst generator frequency so that the cycles land exactly on the first and tenth graticule marks Check that each cycle is within 0 5 minor division of a major graticule mark Select MAG ON from the Operating menu Set the multiburst generator frequency to 2 MHz Check for one cycle per division 1 minor division over the center ten graticule divisions and also at both ends of the magnified sweep using the horizontal position control ignoring the first and last cycle Set the multiburst generator frequency to 1 MHz Select 2H SWEEP f
127. y display page 6 49 All display modes are bad except Picture when no menus are displayed page 6 49 Troubleshooting Flowcharts The troubleshooting flowcharts provide a series of steps to follow which should result in you isolating the faulty module Each flowchart is directly related to a fault symptom listed in Table 6 5 Figure 6 32 on page 6 50 illustrates the connector and pin locations of the circuit board connectors listed in the troubleshooting flowcharts 6 36 WFM 90 WFM 91 Service Manual Troubleshooting Procedures Use this procedure if there is no display after pressing the front panel ON button Is the Backlight broken The Display module will have a rattle inside Press the front panel ON button and then the PIX mode button Is the VIDEO OUT signal good Yes Is the Backlight on Look in the end of the Display module where the high voltage is attached Yes No Testthe Backlight power supply Disconnect the AC Adapter Remove the Display module Attach a 10 22 W resistor between the high voltage connectors using a pair of jumper wires Attach an oscilloscope probe to the end ofthe resistor attached to the orange connector Connectthe oscilloscope ground lead to the GND test point on the Bottom board Set the oscilloscope to 50 V div Reconnect the AC adapter and power up the instrument No Replace the Top board R

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