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Service Guide: Keysight (Agilent) N9912A RF Analyzer

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1. 4 2 Protect Against Electrostatic Discharge 0 4 3 Assembly Replacement Sequence rnrn 4 3 Getting Started with Troubleshooting I 4 4 Check the Basics osse e Gad ax oce tad end eae oe ed wena ute eic e RU RR SMS een a we a Rh a 4 4 Troubleshooting Organization 0 ns 4 5 Power Up 4 6 Front Panel Group Troubleshooting eee II 4 7 Measurement Group Troubleshooting I 4 8 5 Theory of Operation Information in This ence en een need mme eran 5 2 Chapter Five at a Glance m eet n 5 2 Analyzer System Operation en ene hh haee an 5 3 Functional Groups of the 5 3 Front Panel Group 22202004528 Ladders 5 5 Front Panel Interface nee nee mra 5 5 AZ LCD Assembly 5 ech adam yet teas ar RER EN uv RFEU EK va eens 5 6 Measurement GFOUp o aes e de tdt oet ehe wed ur ue x kee CER Add armed fe rp duod 5 7
2. 2 5 3 Tests and Adjustments Information in This 200 0 cece cece III 3 2 Chapter Three hes aha a 3 2 Before You Begin xus oit xa scie trabe wis et Bnd dr dde 3 3 Protect Against Electrostatic Discharge 0 e eee eee eee eees 3 3 Allow the Analyzer to Warm Up cece ence een I res 3 3 Review the Principles of Connector Care 3 4 Service Test ns 3 5 Before Returning an Instrument to a eee eee teenie tees 3 6 Operational Check us sth Shand onem reote Rf e ER 3 6 Performance Tests Keysight N7841A Software 3 7 General Tests rns 3 7 Spectrum Analyzer Specific Tests e m hs 3 7 Adjustments Keysight N7841A Software Package e teen eee eens 3 8 General Adjustments een m 3 8 Service Guide N9912 90003 1 Contents Spectrum Analyzer Specific Adjustments hn 3 8 4 Troubleshooting Information in This Chapter 0 0 c ccc ccc ccc ene III mma 4 2 Chapter Four
3. E 8 5 To View Currently Installed III 8 5 Re Installing m n 8 5 Firmware Upgrades eee mm m m 8 6 To Check the Current Firmware Revision cece Ihren 8 6 Miscellaneous Service and Maintenance 00sec cece cece n 8 7 Cleaning the 1 een een een een aaa 8 7 Battery Maintenance eens 8 7 Service Guide N9912 90003 3 Contents 4 Service Guide N9912 90003 1 Safety and Regulatory Information Service Guide N9912 90003 Safety and Regulatory Information Information in This Chapter Information in This Chapter RF Analyzer N9912A This chapter provides safety information that will help protect you and your network analyzer It also contains information that is required by various government regulatory agencies Chapter One at a Glance Section Title Summary of Content Start Page Descriptions of CAUTION and WARNING symbols sofe a lil used throughout this manual Paga he Sula A list of safety points to consider when servicing your Bags 12 network analyzer A discussion of electrostatic discharge ESD and Electrostatic Discharge Protection related recommendations and requirements for ESD Page 1 5 protec
4. 1 7 2 General Product Information Information in This Chapter 0 0002 c cece eee II s 2 2 Chapter Wo at a Glance tonne exe de sedan dds cede du 2 2 M intenance e ETERNI 2 3 Physical Maintenance mr Lera EG ADR EE MARG 2 3 Electrical 5 9 een ene mh eas 2 3 Analyzer Options so E Seam een thesis Semler 2 3 Option 110 Transmission cece hm 2 3 Option 111 QuickCal REPRE Re ee eme rer ieee been RE evade dia Yd 2 3 Option 230 4 GHz Spectrum Analyzer 0 0 cc ccc ccc Ima 2 3 Option 231 6 GHz Spectrum 2 ccc cence ema 2 3 Option 235 Preamplifier for Spectrum Analyzer 2 3 Option 302 External USB Power Sensor Support 888 2 4 Option 303 Network Analyzer Capability 2 4 Keysight Support Services and 15 n 2 4 Service and Support 0 ccc ccc cnc se eas 2 4 Calibration Options 0 60 06 reread areir kus a he 3 yeh ER aX 2 4 Contacting Keysight e s e ens 2 5 Shipping Your Analyzer to Keysight for Service or
5. 100 kHz to 1 6 MHz 1 6 MHz to 25 MHz 25 MHz to 0 2 GHz 0 2 GHz to 0 8 GHz 0 8 GHz to 1 6 GHz 1 6 GHz to 3 2 GHz 3 2 GHz to 3 4 GHz 3 4 GHz to 4 15 GHz 4 15 GHz to 5 1 GHz 5 1 GHz to 6 2 GHz coo o A j N gt gt Service Guide N9912 90003 5 7 Theory of Operation RF Analyzer Measurement Group N9912A Figure 5 2 Simplified RF Block Diagram A4 RF BOARD SOURCE SYNTHESIZER to 1 6 3 2 GHz 6 2 GHz Q REFLECTOMETER J1100 f w1 Sar our O O eA RF OUT d LO SYNTHESIZER 1 6 3 2 GHz 390 kHz to MULTIPLY AND 6 200290 GHz O DIVIDE O W7 J105 we J101 290 kHz R B X vel NA R lt gt J102 290 kHz Q4 UX a c ao gt ul 2 gt wo lt 5 r4 o E 30 MHz REF 1ST e RF IN w4 p T lt gt lt 2200 w2 Q XR XR DXQ O O ERK RF IN VCO Digital Unlock Control Signals AEN UEM RF2 SA RF1 NA TEMP TEMP SENSOR SENSOR SERIAL BUS B n9912a rf blk 24 August 2009 5 8 Service Guide N9912 90003 RF Analyzer Theory of Operation N9912A Measurement Group CAT NA Section In this section the 30 MHz time base from the 5 system board is used to generate a source signal the source synthesizer that covers the frequency range of 100 kHz to 6 2 GHz The source signal is generally rich in harmonic content This
6. 4 To replace the hinge a Lift the kickstand assembly off of the rear case b Remove and discard the four hinge attachment screws item 2 c Place the new hinge in position and install with four new screws New screws are provided in the Repair and Re assembly Kit d Place the kickstand assembly in place on the rear case and reinstall the hinge cover with new screws provided in the Repair and Re assembly Kit Figure 7 3 Replacing the Hinge 4 places 2 Kickstand backside n9912_90003_703 Service Guide N9912 90003 7 7 Repair and Replacement Procedures RF Analyzer Removing and Replacing the Case Group Parts N9912A Separating the Front and Rear Cases 1 Remove the battery Refer to Removing and Replacing the Main Battery on page 7 5 2 Loosen the six screws item 3 that secure the RF top panel It should not be necessary to remove these screws just loosen them 3 Remove and discard the six screws item 4 that secure the rear case to the front case New screws are provided in the Repair and Re assembly Kit Figure 7 4 Separating the Front and Rear Cases 1 n9912 90003 704 4 4 7 8 Service Guide N9912 90003 RF Analyzer Repair and Replacement Procedures N9912A Removing and Replacing the Case Group Parts 4 Separate the cases and position the rear case to one side as shown in Figure 7 5 to allow access to the blank side panel and strap handle 5 Remove the
7. Connector CN2 for Cable W13 n9912 90003 715 Service Guide N9912 90003 7 21 Repair and Replacement Procedures RF Analyzer Removing and Replacing the Front Panel Group Assemblies N9912A Replacing the A3 Front Panel Interface Board FPIB IMPORTANT The A3 front panel interface board contains a Lithium ion battery Refer to Battery Ce Ole JS koe 10 1 12 13 Disposal on page 1 7 for important instructions on disposing of this printed circuit board with the battery attached If necessary the battery can be removed from the printed circuit board and disposed of separately Perform the steps under Pre replacement Procedure on page 7 18 Remove the four screws item 2 that secure the LCD shield and remove the LCD shield Discard the four screws new ones are provided in the Repair and Re assembly Kit Be careful The A2 LCD display is now loose and will fall out of the front case if the case is tipped Disconnect the RPG cable W12 at the A3 FPIB connector as indicated Disconnect the A2 LCD to FPIB cable W113 at the A3 FPIB connector as indicated Remove the nine screws item 3 that secure the A3 FPIB to the front case Push the nine rubber nubs through the A3 FPIB to release the A1 keypad The A1 keypad is permanently attached to the front case and must remain Position the new A3 FPIB in the front case over the A1 keypad and using needle nose pliers pull the nine rubber nubs on the A1 k
8. Contacting Keysight on page 2 5 Calibration Options Commercial Calibration Certificate with Test Data A complete set of measurements that test the analyzer to the manufacturer s published specifications It includes a calibration label a calibration certificate and the corresponding calibration data report This calibration conforms to ISO 9001 ISO 17025 Standards Compliant Calibration A complete set of measurements that test the analyzer to the manufacturer s published specifications It includes a calibration label an ISO 17025 calibration certificate and the corresponding calibration data measurement uncertainties and guardbands on all customer specifications This calibration conforms to 150 17025 and ISO 9001 This calibration option is available at the time of purchase or can be obtained later by sending your analyzer to Keysight for calibration Refer to Shipping Your Analyzer to Keysight for Service or Repair 2 4 Service Guide N9912 90003 RF Analyzer General Product Information N9912A Keysight Support Services and Assistance ANSI 2540 Standards Compliant Calibration A complete set of measurements that test the analyzer to the manufacturer s published specifications It includes both pre and post adjustment data with measurement uncertainty information compliant to the ANSI NCSL Z540 standard This calibration option is available at the time of purchase or can be obtained later by sending your analyzer to K
9. Do Clean and zero the gage before use Do Not Use an out of specification connector Use the correct gage type Use correct end of calibration block Gage all connectors before first use Making Connections Do Align connectors carefully Do Not Apply bending force to connection Make preliminary connection contact lightly Over tighten preliminary connection Turn only the connector nut Twist or screw any connection Use a torque wrench for final connection Tighten past torque wrench break point a Cleaning connectors with alcohol shall only be done with the instrument s power cord removed and in a well ventilated area Allow all residual alcohol moisture to evaporate and the fumes to dissipate prior to energizing the instrument 3 4 Service Guide N9912 90003 RF Analyzer Tests and Adjustments N9912A Service Test Equipment Service Test Equipment The test equipment required for the TME based N7841A test and adjustment software is listed in the N7841A help file The following additional test equipment is recommended when servicing the N9912A analyzer Main Battery Required if the analyzer is returned for service without a battery Refer to Table 6 1 on page 6 14 for part numbers USB flash drive Used for firmware upgrades option installation etc Also known as USB memory stick Must be 128 MB or larger Small free standing fan Used to cool the analyzer if internal temperature is too
10. The circuitry on the A4 RF board has five special sections that may be powered down for the purpose of power management These sections may be selectively powered down via load switching when not required for the current operating mode of the analyzer The sections that may be selectively powered down are Source most of the source synthesizer circuitry LO most of the LO synthesizer circuitry e SA most of the first second and third converter circuitry Reflectometer put into a low power state High Band Pre amp high band section of the pre amp turned off The load switching for the Source LO and SA sections is accomplished on the Ab system board via the Analog Power Supply Load Switching circuitry The load switching for the Reflectometer and High Band Preamp is accomplished on the A4 RF board Other Circuitry The CPLD Complex Programmable Logic Device communicates witbh the FPGA on the 5 system board via Serial Bus A It provides the digital control for the functions on the A4 RF board It also reads the VCO 5 10 Service Guide N9912 90003 RF Analyzer Theory of Operation N9912A Measurement Group unlock signals Serial Bus B allows the System Monitor on the Ab system board to read two temperature sensors and the ID EPROM for the A4 RF board RF1 temperature sensor NA Temp Sensor is near the RF OUT connector on the side of the A4 RF board that is away from the 5 system board This temperatu
11. Go to Measurement Group Troubleshooting on page 4 8 Service Guide N9912 90003 4 5 Troubleshooting RF Analyzer Power Up Troubleshooting N9912A m Power Up Troubleshooting If the display is operational but the unit does not boot up successfully into CAT mode Make sure there is sufficient power for the unit to operate Try re installing firmware using the firmware upgrade process described in Chapter 8 Assume corrupted firmware on the A6 SOM board follow the Install Firmware from SD Card near the end of Chapter 7 If the display is dark but the unit may have booted successfully Wait for two minutes to make sure the boot process has completed then press any front panel key If the boot process has completed successfully the keypad will flash when the key is pressed 4 6 Service Guide N9912 90003 RF Analyzer Troubleshooting N9912A Front Panel Group Troubleshooting Front Panel Group Troubleshooting If no sound Enter a value of just decimal point for a frequency A double beep should occur Plug headphones into the unit if there is no sound from the internal speaker The internal speaker is disabled when headphones are plugged in If the display is dark no backlight Press Mode gt System 7 gt the left most soft key gt the next to the left most soft key gt press the up arrow many times This should bring the display brightness setting to a viewable level Service Guide N
12. RFI O strip hollow 2 LCD lens filter 3 Keypad overlay 4 Model label nameplate overlay 4 GHz 5 Model label nameplate overlay 6 GHz 5 Rear Enclosure N9912 60022 Rear Enclosure Assembly lIncludes Rear case 6 Assembly RF gap pad 7 Rear panel overlay 8 1 0 Panel Assembly lIncludes 1 0 Panel System board connector panel 1 0 side panel 9 Asssmbl N9912 60023 1 Overlay 1 0 panel top USB 10 y Overlay 1 0 panel middle SD 11 Overlay 1 0 panel bottom LAN 12 Kick Stand Assembly Includes Kickstand 13 Friction hinge 14 Kick Stand Assembly N9912 60028 1 Screw for hinge qty 4 15 Hinge cover 16 Screw for hinge cover qty 4 17 Spacer for hinge qty 2 29 Separately Replaceable Individua Parts and Assemblies 4 3110 0654 1 Friction hinge 15 0515 1940 4 Screw machine w patch lock pan head M2 5 x 6 mm 16 W1312 40068 1 Hinge cover 17 0515 5133 4 Screw machine button head M3 0 x 8 mm 18 0515 5153 6 Screw machine w flat washer pan head M3 0 x 35 mm 19 N9912 60007 1 Battery cable 20 W1312 40060 1 Battery door cover 21 N9912 40006 2 Hole plugs 22 0515 1521 2 Screw machine 90 deg flat head M3 0 x 5 mm 23 N9910 80002 1 Strap handle 1 Each time the N9912A case is opened for any reason you must order a Repair and Re assembly Kit See Miscellaneous Parts
13. replace line fuse only with same type and rating The use of other fuses or material is prohibited The detachable power cord is the instrument disconnecting device It disconnects the mains circuits from the mains supply before other parts of the instrument The front panel switch is only a standby switch and is not a LINE switch disconnecting device Service Guide N9912 90003 RF Analyzer Safety and Regulatory Information N9912A Electrostatic Discharge Protection Electrostatic Discharge Protection Protection against electrostatic discharge ESD is essential while removing assemblies from or connecting cables to the network analyzer Static electricity can build up on your body and can easily damage sensitive internal circuit elements when discharged Static discharges too small to be felt can cause permanent damage To prevent damage to the instrument always have a grounded conductive table mat in front of your test equipment e always wear a grounded wrist strap connected to a grounded conductive table mat having a 1 MQ resistor in series with it when handling components and assemblies or when making connections always wear a heel strap when working in an area with a conductive floor If you are uncertain about the conductivity of your floor wear a heel strap always ground yourself before you clean inspect or make a connection to a static sensitive device or test port You can for example grasp the grounded outer s
14. 18 Removing All Measurement Group Assemblies as One Unit Disconnect cable W14 from A3 front panel interface board here D _ So TT Tee pg te n PEE e Side Panel Remove adhesive tape and disconnect cable W11 here n9912 90003 717 7 26 Service Guide N9912 90003 RF Analyzer Repair and Replacement Procedures N9912A Removing and Replacing the Measurement Group Assemblies Replacing the RF Top Panel Assembly 1 gt o Separate the front and rear cases Refer to Separating the Front and Rear Cases on page 7 8 Remove all measurement group assemblies as one unit Refer to Removing All Measurement Group Assemblies as One Unit on page 7 25 Unplug the two connector plugs tethered caps from the type N RF connectors Disconnect cable W3 Remove the six screws item 1 and lift the RF top panel over the type N RF connectors Position the new RF top panel over the type N RF connectors and loosely reinstall the six screws item 1 Do not tighten these screws at this time they will be tightened after the front and rear cases have been combined Connect cable W3 to the A5 system board connector There should be an audible click when the connector is fully in place Position tuck the cable W3 into the cavity above the A5 system board to avoid interference with nearby parts Plug the two connector plugs tethered caps back into the type N RF co
15. 2 5 Service Guide N9912 90003 2 5 General Product Information RF Analyzer Keysight Support Services and Assistance N9912A 2 6 Service Guide N9912 90003 3 Tests and Adjustments Service Guide N9912 90003 Tests and Adjustments Information in This Chapter RF Analyzer N9912A Information in This Chapter This chapter contains procedures to help you check verify and adjust your N9912A analyzer e The checks verify the operation of the assemblies in your analyzer The adjustments allow you to tune your analyzer for maximum response NOTE The Keysight N7841A software package is required to test and adjust your analyzer This software package must be purchased separately It can be downloaded from the Internet and a license purchased on line or it can be ordered on a CD ROM Go to www keysight com find calibrationsoftware for further information The help file for the N7841A software package is also available at this URL Chapter Three at a Glance Section Title Summary of Content Start Page Items to consider or procedures to perform before testing is begun Verify the operating environment Before You Begin e Protect Against Electrostatic Discharge ESD Page 3 3 e Allow the Analyzer to Warm Up Review the Principles of Connector Care A list of additional equipment recommended for servicing the Service Test Equipment N9912A analyzer Page 3 5 Before Returning an A list of things to do
16. Charger and Manager circuit e It interfaces to the Serial Bus B for communication with the temperature sensors and ID EPROM s on the printed circuit boards tcommunicates to the SOM board CPU via a serial port UART tstores the instrument model number and serial number Battery Charger and Manager This circuitry controls charging of the battery based on a battery charger IC This IC is powered by a digital output on the System Monitor The System Monitor has the capability to reset the IC if required by recycling the power to the IC This circuitry also controls the source of the Unreg DC Batt or Ext DC It reads the battery pack information via the Smart Batt Bus Batt Neg is connected to the Ab ground plane There is an input inrush current control circuit on the Ext DC input that limits inrush current to 4 amps Analog Power Supplies and Load Switching Seven different analog supply voltages are generated from the Unreg DC All of these are used on the A4 RF board and some are used on the A5 system board Some sections of the circuitry on the A4 RF board may be switched to low power modes to conserve power and minimize heat This is accomplished through load switching See Power Management Circuitry on page 5 10 for more information The System Monitor controls the on off functions of the analog power supplies All are on or off together 5 12 Service Guide N9912 90003 RF Analyzer Theory of Operation N9912
17. Dodging Adjustment 3 8 Service Guide N9912 90003 4 Troubleshooting Service Guide N9912 90003 4 1 Troubleshooting RF Analyzer Information in This Chapter N9912A Information in This Chapter The information in this chapter helps you Identify the portion of the analyzer at fault Locate the specific troubleshooting procedure to identify the assembly or peripheral at fault The sections in this chapter are arranged in a logical troubleshooting order The following table lists the sections and a brief summary of what to look for in that section Chapter Four at a Glance Section Title Summary of Content Start Page Getting Started with Troubleshooting A starting point to begin troubleshooting Page 4 4 Power up problems Power Up Troubleshooting probleme 4 6 Problems with the front panel assemblies of the Front Panel Group Troubleshooting analyzer Page 4 7 Problems with the measurement group assemblies of Measurement Group Troubleshooting the analyzer Page 4 8 4 2 Service Guide N9912 90003 RF Analyzer Troubleshooting N9912A Protect Against Electrostatic Discharge ESD Protect Against Electrostatic Discharge ESD This is important If not properly protected against electrostatic discharge can seriously damage your analyzer resulting in costly repair CAUTION To reduce the chance of electrostatic discharge follow all
18. Interface Board e A2LCD Assembly Refer to Figure 5 1 for a simplified overall block diagram which includes the front panel group A3 Front Panel Interface Board The main function of the A3 front panel interface board is to support the user interface but it also contains the digital power supplies Microcontroller and CPLD The Microcontroller and CPLD sense the keypad keys and the RPG rotary pulse generator knob on the front panel The Microcontroller communicates with the A5 system board via a USB interface There is no separate ID EPROM on the front panel interface board All ID information is stored in the Microcontoller Front Panel LED s and ON OFF Button The power for the Keypad LED s generated on the A3 front panel interface board is derived from the 5 V digital supply The Keypad LED s are turned on for a few seconds following each key press This function is controlled by the firmware on the A6 SOM board The On Off LED is controlled by a signal from the Ab system board The connections for the On Off Button and LED are direct to the A5 system board Real Time Clock Battery The battery for the RTC real time clock on the A6 SOM board is located on the A3 front panel interface board and is connected to the SOM board via the system board Backlight Power Power for the backlight on the A2 LCD assembly is generated on the front panel interface board Digital 5 volts is converted to approximately 25 volts
19. N9912 90003 RF Analyzer General Purpose Maintenance and Service Procedures N9912A Options Options Installed options determine the functionality of the analyzer There is a license associated with each option Every instrument has at least one option installed 104 or 106 This option determines the maximum frequency of the instrument Additional options enable additional modes or other functionality Note that the maximum frequency of the instrument may not be upgraded Option 104 or 106 is installed in the factory and may not be changed in the field To View Currently Installed Options Press System 7 Press System Configuration Press Options Press Show Options A list of the currently installed options is displayed Re Installing Options If an instrument looses all of its options i e it reports or shows no options the only functionality available will be CAT up to 4 GHz When the A6 SOM board is replaced it is necessary to re load the license files because the license and option information is stored on the A6 SOM board Process for obtaining and re installing options 1 Send an email to ctd soco_support keysight com with the following information Indicate that you need previously issued licensed for a FieldFox repair Model number and serial number of the instrument Maximum frequency of the instrument from the label above the display Alistof options from the serial number label on the back o
20. Procedures are provided for preparing configuring and making measurements with the analyzer The Quick Reference Guide included with the product is an abbreviated form of the User s Guide containing some of the most commonly referred to information The pages of the Quick Reference Guide are laminated with clear plastic to resist damage when used outdoors Printing Copies of Documentation from the Web To print copies of documentation from the Web download the PDF file from the Keysight web site Go to www keysight com Enter the document s part number located on the title page in the Search box Click Search Service Guide N9912 90003 Contents 1 Safety and Regulatory Information Information in This IIR mere 1 2 Chapter One at a Glance e haa 1 2 Safety Symbols be Erbe te aras IPs 1 3 General Safety Considerations ccc cen een e here 1 3 Safety Earth Ground NR eee da RAISE hb ea 1 3 Before Applying Power 0 ccc ccc cece I Ih a e aha 1 4 SEI TEM 1 4 Electrostatic Discharge 1 5 Regulatory Information 0 ccc ccc ne nee nee nee need beeen anes 1 6 Instrument Markings me mh haa 1 6 Battery Disposal 2 deer
21. See Separating the Front and Rear Cases on page 7 8 2 Note the orientation of the cable for installation of the new cable then using a small flat blade screwdriver to move the cable connector release the retention clips on the cable connector and remove the cable from the rear case Figure 7 7 Replacing the Battery Cable Use a small flat blade screwdriver Use a small flat blade screwdriver here to release the connector from here to release the connector from under the retention clip Retention Clips under the retention clip Battery Cable Connector n9912_90003_707 3 When installing the new battery cable make sure that the connector snaps into place 4 Reinstall the rear case onto the front case See Combining the Front and Rear Cases Replacing the Rear Case 1 Separate the front and rear cases See Separating the Front and Rear Cases 2 Carefully remove the serial number label and the Windows CE label from the back of the old rear case and apply the labels to the new rear case 3 Remove the kickstand assembly from the old rear case and install it on the new rear case See Replacing the Kickstand Hinge Cover and Hinge 4 Remove the battery cable from the old case and install it in the new case See Replacing the Battery Cable 5 Install the new rear case onto the front case See Combining the Front and Rear Cases Replacing the Strap Handle 1 Separate the front and rear cases to the positions shown in Fig
22. also connected 2 Does the analyzer turn On and Off when the On Off Button is pressed When the unit is on the green LED below the button should light 3 Does the analyzer power up normally into CAT mode If not see Power Up Troubleshooting on page 4 6 4 f other equipment cables and connectors are being used with the analyzer make sure they are clean connected properly and operating correctly 5 Review the procedure for the measurement being performed when the problem appeared Are all the settings correct If not correct them 6 If the analyzer is not functioning as expected return it to a known state by pressing the Preset key 7 Ifthe problem is thought to be due to firmware check to see if the instrument has the latest firmware before starting the troubleshooting procedure Refer to Firmware Upgrades in Chapter 8 for instructions 4 4 Service Guide N9912 90003 RF Analyzer Troubleshooting N9912A Getting Started with Troubleshooting Troubleshooting Organization Follow the flowgraph in Figure 4 1 to help direct you to the correct section for troubleshooting the analyzer Figure 4 1 Troubleshooting Organization Flowchart Does the analyzer Go to Power Up Troubleshooting power up normally on page 4 6 into CAT mode Does the analyzer keypad and display operate properly Troubleshooting on page 4 7 Go to Front Panel Group Does the analyzer perform measurements properly
23. ass 5 27 Erase User Data Utility irera nt vie bon deque E ARRA 5 27 EnrorLog ee 5 27 Firmware Upgrades 5 28 2 Service Guide N9912 90003 Contents AG Ces TTE 5 29 6 Replaceable Parts Information in This Chapter e mm n 6 2 Chapter Six at a Glance e eese ott Dacha d dd 6 2 sese m s 6 3 Assembly Replacement 6 4 Replaceable Parts 1 9 Im 6 5 oa poate Pane 6 5 Front Panel Group ERU FREE ies dhladiieieis 6 6 Measurement Groupes ieir ene E A E 6 8 Case rernm 6 11 Miscellaneous Parts i oie edet gad am od aed ciate E Gl ei dete aged 6 14 7 Repair and Replacement Procedures Information in This m m 7 2 Chapter Seven at a Glance 0 ccc ccc ccc cece eee he m aan 7 2 Personal Safety Warnings 0 ccc cece m s 7 3 Safety Earth Ground e 7 3 Elect
24. before returning an instrument to a customer 46 Instrument to Customer after servicing is completed Operational heak An operation check that should be performed before returning an Page 3 6 instrument to a customer Performance Tests A list of performance tests included in the Keysight N7841A Keysight N7841A software package Page 3 7 Software Package Adjustments Keysight A list of adjustments included in the Keysight N7841A software N7841A Software package Page 3 8 Package a The Keysight N7841A software package must be purchased separately Go to www keysight com find calibrationsoftware for information 3 2 Service Guide N9912 90003 RF Analyzer Tests and Adjustments N9912A Before You Begin Before You Begin Before checking verifying or adjusting the analyzer refer to the following paragraphs to Make sure the operating environment is within 19 to 27 C and 5 to 95 humidity Make sure that proper electrostatic discharge ESD protection is provided Review the principles of connector care Protect Against Electrostatic Discharge ESD This is important If not properly protected against electrostatic discharge can seriously damage your analyzer resulting in costly repair CAUTION To reduce the chance of electrostatic discharge follow all of the recommendations outlined in Electrostatic Discharge Protection on page 1 5 for all of the procedures in this chapter Allow the Analyzer
25. board top shield and six new screws item 5 to secure the Ab system board to the RF bottom shield Torque these ten screws in the sequence shown by the circled numbers EDO Repeat this torque sequence one additional time Reinstall the A6 SOM board and reinstall or reconnect all coax cables that were removed or disconnected previously Refer to Replacing the A6 SOM Board and Flexible RF Cables on page 7 29 Remove the system board to FPIB cable from the old Ab system board and install it on the new board Reinstall the 1 0 side panel Refer to Replacing the 1 0 Side Panel Doors and Gasket on page 7 12 Perform the steps under Post replacement Procedure on page 7 37 Service Guide N9912 90003 7 31 Repair and Replacement Procedures RF Analyzer Removing and Replacing the Measurement Group Assemblies N9912A Figure 7 22 Replacing the A5 System Board Enlarged Side View Cable 5 A4J102 to A5J18 Cable W6 Connector marked with red A4J101 to A5J14 Single Coaxial Cable Replacement Assembly Cable W4 S A4J104 to A5J19 Cable W7 Amea A4J105 to A5J20 Cable Signals T W4 SA IF l W5 NA R IF W6 IF W7 30 MHz ref lal Dm a ue 4 4 places on shield Dowel Pin Dowel Pin on cable W6 5 Coax Cable Assembly 8 W AD Ll W4 W6 7 uu nf p 2 S Cable W6 i Red connector 5 System Board Cabl A5
26. firmware to enable use of this pre amp The pre amp is always bypassed in CAT and NA modes Typical gain of the pre amp is 22 dB It has two sections high band and low band The low band section covers up to 2 7 GHz Converters Three stages of conversion produce the 37 5 MHz SA IF signal that goes to the 5 system board The first converter stage mixes the incoming signal with the LO output Input signals below 2 7 GHz are up converted and input signals above 2 7 GHz are downconverted Service Guide N9912 90003 5 9 Theory of Operation RF Analyzer Measurement Group N9912A Spur avoidance is accomplished by slightly shifting the output frequency of the first converter stage When the output frequency of the first converter is shifted the second converter compensates for the shift The third converter output frequency is fixed at all times SA Frequency Bands The frequency bands for the SA function are as listed below Up to 2 7 GHz bands 1 4 are considered LOW bands and above 2 7 GHz bands 5 11 are considered HIGH bands Different hardware is used for each type Analyzer Analyzer Band Start Frequency Stop Frequency MHz MHz 1 0 000 10 000 2 30 000 715 000 3 715 000 1665 000 4 1665 000 2700 000 5 2700 000 3313 500 6 3313 500 3500 000 7 3500 000 4263 500 8 4263 500 4300 000 9 4300 000 5200 000 10 5200 000 5936 500 11 5936 500 6000 000 Power Management Circuitry
27. install a new one Position the new type N RF connector in the RF bottom shield making sure that it aligns with the cable connector underneath Loosely install the cable connector nut Install new RFI O ring over the new type N RF connector in the position shown Loosely reinstall the two screws item 2 Note the location for these two screws in the illustration To ensure proper alignment install two additional screws finger tight in the two empty holes in the type N RF connector then tighten the two screws that secure the connector Remove the two alignment screws Tighten the cable connector nut s on cable W1 or W2 Perform the steps under Post replacement Procedure on page 7 37 Figure 7 20 Replacing the Type N RF Connectors and RF Cables RFI O ring Type N RF Connector RFI O ring Insulator Insulator Cable W2 2 Cable W1 2 places on each connector n9912_90003_719 7 28 Service Guide N9912 90003 RF Analyzer Repair and Replacement Procedures N9912A Removing and Replacing the Measurement Group Assemblies Replacing the A6 SOM Board and Flexible RF Cables 1 2 Separate the front and rear cases Refer to Separating the Front and Rear Cases on page 7 8 Remove all measurement group assemblies as one unit Refer to Removing All Measurement Group Assemblies as One Unit on page 7 25 To replace the A6 SOM board a Remove the four screws item 3 that secure the A6 SOM board Discard
28. is acceptable because the signal is used with tuned receivers The source frequency bands are listed below 100 kHz to 1 6 MHz 1 6 MHz to 25 MHz 25 MHz to 0 2 GHz 0 2 GHz to 0 8 GHz 0 8 GHz to 1 6 GHz 1 6 GHz to 3 2 GHz 3 2 GHz to 6 2 GHz A ww N gt The RF Out attenuator between the source and the reflectometer has two settings nominal values of 0 dB and 30 dB The setting is determined by the Hi Lo power setting on the user interface The reflectometer performs three functions It passes the source output signal to the RF OUT port It samples the source output to the RF OUT port It samples the incoming signal at the RF OUT port The sampled signals are mixed with the LO signal to produce two 290 kHz IF signals NA A and NA R The reflectometer dissipates up to 1 5 watts when active The RF OUT port has a DC isolation capacitor 0 056uF SA RF Section In this section the signal at the RF IN port is first routed through a DC isolation capacitor 0 056 uF then through the RF In attenuator RF In Attenuator The RF In attenuator covers the range of 0 dB to 31 dB in one dB steps An adjustment determines compensation for each of the 32 steps over 11 frequency bands see SA Frequency Bands on page 5 10 This compensation provides nominal 1 0 dB steps Pre Amp The pre amp that follows the RF In attenuator may be in or out during the SA mode Option 235 is required for the
29. of the recommendations outlined in Electrostatic Discharge Protection on page 1 5 for all of the procedures in this chapter Assembly Replacement Sequence After identifying the problem requiring an assembly to be replaced follow these steps Step 1 Order a replacement assembly Refer to Chapter 6 Replaceable Parts Step 2 Replace the faulty assembly and determine what adjustments are necessary Refer to Chapter 7 Repair and Replacement Procedures Step 3 Perform the necessary adjustments Refer to Chapter 3 Tests and Adjustments Step 4 Perform the necessary performance tests Refer to Chapter 3 Tests and Adjustments Service Guide N9912 90003 4 3 Troubleshooting RF Analyzer Getting Started with Troubleshooting N9912A Getting Started with Troubleshooting Where you begin troubleshooting depends upon the symptoms of the failure Start by checking the basics as outlined in the following section Also review the flowchart in Figure 4 1 on page 4 5 You should then be able to determine where in the troubleshooting procedure to begin to locate the failed assembly Check the Basics A problem can often be solved by repeating the procedure you were following when the problem occurred Before calling Keysight Technologies or returning the instrument for service please perform the following checks 1 Does the analyzer have power available It is recommended that the battery is installed and the AC power adapter is
30. replacement 7 6 L LAN interface general information 5 29 LCD illustrated 6 5 manual check 7 38 operation 5 6 parts list 6 5 removal and replacement 7 18 LCD shield removal and replacement 7 18 lithium battery disposal 1 7 load instrument serial number 7 38 M main battery removal and replacement 7 5 maintenance battery maintenance 8 7 cleaning 2 3 cleaning the display 8 7 manual check keyboard 7 38 LCD 7 38 RPG 7 38 manual checks and procedures 7 38 measurement group operation 5 7 troubleshooting 4 8 measurement group assemblies removal and replacement 7 25 miscellaneous replaceable parts part numbers 6 14 N N7841A performance tests 3 7 0 operating modes 5 20 CAT and NA 5 21 PM 5 23 SA 5 23 operation A4 RF board 5 7 Ab system board 5 12 A6 SOM board 5 16 Index 2 battery 5 16 5 18 battery charging management 5 18 CAT and NA modes 5 21 CPU board 5 16 front panel group 5 5 front panel interface board 5 5 grounding 5 17 in modes 5 20 LCD 5 6 measurement group 5 7 PM mode 5 23 power 5 17 power control 5 17 power management 5 17 power states 5 17 power supplies 5 17 SA mode 5 23 smart power management 5 17 theory of 5 3 operational check 3 6 operational files 5 27 option calibration 2 4 service and support 2 4 Option 1A7 ISO 17025 standards compliant calibration 2 4 Option A6J ANSI Z540 standards compliant calibratio
31. should occur Re Install Options See the Service Related User Operations section of Chapter 8 for information on re installing options 7 38 Service Guide N9912 90003 8 General Purpose Maintenance and Service Procedures Service Guide N9912 90003 General Purpose Maintenance and Service Procedures RF Analyzer Information in This Chapter N9912A Information in This Chapter Chapter Eight at a Glance Section Title Summary of Content Start Page Service Related User Operations How to page 8 3 view options currently installed on your analyzer view the current firmware revision view the error log view temperature readings erase user data Options How to page 8 5 view the currently installed options e re install options after repair Firmware Upgrades How to page 8 6 check your analyzer s current firmware revision where to locate additional information about firmware upgrades Miscellaneous Service and Information about page 8 7 Maintenance cleaning the display battery maintenance 8 2 Service Guide N9912 90003 RF Analyzer General Purpose Maintenance and Service Procedures N9912A Service Related User Operations Service Related User Operations To View Currently Installed Options Press System 7 Press System Configuration Press Options Press Show Options A list of the currently installed options is displayed To View the Cur
32. the A6 SOM board There is limited access to the file system Most memory is in protected region and not directly accessible by the user The user accessible memory is under UserData See the File Management section of the FieldFox User s Guide for instructions on saving recalling and managing files in the unprotected memory User Accessible Files Directory structure below UserData in the A6 SOM board flash memory approximately 20 MB External USB flash memory plugged in the analyzer External SD memory card plugged into the analyzer NOTE When copying files a Copy directory is created at the root of the destination device as the destination for the copied file s This characteristic generally makes it impossible to copy a file into the desired directory under UserData in the A6 SOM board flash memory This limits the usefulness of copying files to or within UserData Operational Files Results from adjustments performed under TME see Chapter 3 not directly available to user File resulting from CAT NA user calibration not directly available to user Cal kit definition files stored in UserData calkits Cable definition files stored in UserDataNCables Errorlog not directly available to user See Error Log further on in this section for accessing error log information Erase User Data Utility A utility to erase all directories and files in the UserData directory is available After the flash
33. 912 90003 Web on page iv ESD Supplies Adjustable antistatic wrist strap 9300 1367 Antistatic wrist strap grounding cord 5 foot length 9300 0980 Static control table mat and earth ground wire 9300 0797 ESD heel strap 9300 1126 Battery Lithium ion 11 1 V rechargeable LCD gauge 1420 0908 a Refer to Battery Disposal on page 1 7 for instructions on disposing of the old battery 6 14 Service Guide N9912 90003 7 Repair and Replacement Procedures Service Guide N9912 90003 Repair and Replacement Procedures Information in This Chapter Information in This Chapter RF Analyzer N9912A This chapter contains procedures for removing and replacing the major assemblies of your Keysight Technologies PNA series microwave network analyzer Chapter Seven at a Glance Section Title Summary of Content Start Page Personal Safety Warnings Warnings and cautions pertaining to personal safety Page 7 3 Electrostatic Discharge ESD Information pertaining to ESD protection Page 7 3 Protection Assembly Replacement Sequence A step by step procedure for how to identify the faulty Page 7 4 assembly replace it with a new one and re adjust your analyzer when done Table of Removal and Replacement A table of removal and replacement procedures andthe Page 7 4 Procedures corresponding page number where they are located Removal and Replacement Procedures The actual procedure
34. 912 90003 7 15 Repair and Replacement Procedures RF Analyzer Removing and Replacing the Case Group Parts N9912A 5 Position the rear case on top of the front case and to one side as shown 6 Place the blank side panel in the groove in the front case being careful not to damage the gasket 7 Position the strap handle over the two dowel pins as shown Figure 7 12 Combining the Front and Rear Cases 2 Dowel Pin 2 ga Install new gasket in groove in blank side panel 2M Strap Handle Battery Dowel Blank Cable Pin Side Panel W10 n9912 90003 712 7 16 Service Guide N9912 90003 RF Analyzer Repair and Replacement Procedures N9912A Removing and Replacing the Case Group Parts 8 Position the rear case directly over and aligned with the front case and the side panels as shown 9 Make sure the battery cable is tucked in between the measurement group assemblies and the blank side panel and that it is not in the path of the screw hole indicated 10 Firmly press the cases together being careful not to damage the gaskets 11 Install six new screws item 7 to secure the rear case to the front case These new screws are provided in the Repair and Re assembly Kit 12 Tighten the six screws item 8 that secure the RF top panel Figure 7 13 Combining the Front and Rear Cases 3 n9912 90003 713 7 7 13 Reinstall the battery Refer to Removing and Replacing the Main Battery on page 7 5 Service Gui
35. 9912 90003 4 7 Troubleshooting RF Analyzer Measurement Group Troubleshooting N9912A Measurement Group Troubleshooting If calibration with the standard Type N cal kit 1250 3607 or N9910X 800 gives unexpected results Make sure the unit is warmed up for at least 30 minutes Make sure the correct cal kit definition is being used erase user data to force use of factory cal kit definitions see Chapter 8 for information on the Erase User Data Utility If there appears to be LAN communication problems Use only 100 Base T LAN connections Sometimes there are problems with the slower speed 10 Base T connections If ADC Overload error messages are displayed during S21 or insertion loss measurements Perform the ADC Overload Adjustment under Adjustments Keysight N7841A Software Package in Chapter 3 4 8 Service Guide N9912 90003 5 Theory of Operation Service Guide N9912 90003 5 1 Theory of Operation RF Analyzer Information in This Chapter N9912A Information in This Chapter This chapter provides a general description of the operating theory of the N9912A analyzer Theory of operation is explained to the assembly level only Component level circuit theory is not provided Simplified block diagrams are included for each functional group Chapter Five at a Glance Section Title Summary of Content Start Page Analyzer System Operation A summary of the theory of operation for the anal
36. A Measurement Group except for power sequencing This circuitry also monitors the Ext DC input and if below 10 8 volts or above 21 volts it disconnects this input from the Unreg DC There are two DC power supply lines 1 Ext DC and 2 Batt Each has a 5 amp fuse immediately after the connector on the printed circuit board FPGA This FPGA provides the interface between the A6 SOM board and the ADC provides miscellaneous interfaces for circuitry on the A4 RF board and communicates with the CPU via the USB interface Time Base The Time Base is an internal TCXO that produces 30 MHz signals for use throughout the analyzer A 10 MHz signal at the EXT TRIG EXT REF input may be used to provide and external time base The external time base function is controlled via the user interface Refer to the External Frequency Reference section of the FieldFox User s Guide for additional information There is no external trigger EXT TRIG function at the time of this printing Filters MUX and ADC s The three Filters filter the IF signals in preparation for the ADC Filter characteristics are fixed not programmable The ADC s digitize each of the IF signals received from the A4 RF board The input to one of the ADC s is multiplexed between the NA A and SA input signals Since the NA R and NA A signals are sampled simultaneously phase relationship is preserved The 14 bit ADC s sample at a rate of 30 mega samples per s
37. AQ RE Boal 2 T 5 7 AS System Board osi doch 5 12 AB S0M Bo td Sagi ca duned eed indies dedit ey 5 16 NETT 5 16 Grounding and n e 5 17 ELMTUTTTTTT 5 17 Voltages and Power Supplies 0 ccc ccc cece ccc nee mh ran 5 17 Power Control and Management 5 17 Battery Related Information 5 18 Operation Modes acutae neu peret a quaii Reate adit dis eden tt eod dide 5 20 CAT and NA Modes Te hp CREUSE 5 21 RW Dn sie Oe 5 23 Power Meter 0c ccc hh haa haa 5 23 Temperature Related Information IRR n 5 24 User Calibration in CAT and NA 5 25 Port Calibration xcix eid wa eurer hcc e Se Awana ee REG RN do as men 5 25 Two Port Calibration eio LER Fere ade Magee mede xS d 5 26 Bn rg p 5 26 Firmware Related 5 27 General Descriptions un s et Rl ne DR 5 27 User Accessible Files em 5 27 Operational Files oaa
38. Analyzer Removing and Replacing the Front Panel Group Assemblies N9912A Replacing the Real Time Clock RTC Battery Located on the A3 Front Panel Interface Board FPIB IMPORTANT The RTC battery is a Lithium ion battery and must be disposed of properly Refer to Battery Disposal on page 1 7 for important instructions on disposing of this battery NOTE A soldering tool is required for this procedure 1 Perform the steps under Pre replacement Procedure on page 7 18 2 Unsolder the RTC battery from the A3 FPIB 3 Insert and solder the new RTC battery into place 4 Perform the steps under Post replacement Procedure on page 7 24 Figure 7 17 Replacing the RTC Battery A3 Front Panel Interface Board FPIB RTC Battery Dispose of properly Post replacement Procedure 1 Reinstall the measurement group assemblies RF top panel A4 RF board 5 system board and SOM board as one unit with the 1 0 panel attached Refer to Removing and Replacing the Measurement Group Assemblies on page 7 25 2 Combine the front and rear cases Refer to Combining the Front and Rear Cases on page 7 15 7 24 Service Guide N9912 90003 RF Analyzer Repair and Replacement Procedures N9912A Removing and Replacing the Measurement Group Assemblies Removing and Replacing the Measurement Group Assemblies Tools Required T 8 TORX driver set to 6 in Ib T 10 TORX driver set to 9 in Ib 5 16 inch open end torque wrench set t
39. BOARD SOURCE SYNTHESIZER 1 6 3 2 GHz vco qf qum EE AND zT 311001 w1 gt gt gt ROUT O RFOUT O ATTEN REFERENCE PATH LO SYNTHESIZER _ TOIFROM A5 SYSTEM BOARD N 1 6 3 2 GHz VCO n9912a_rf_blk_one_port 4 October 2008 The source and receiver step through each frequency point in the sweep Service Guide N9912 90003 5 21 Theory of Operation RF Analyzer Operation in Modes N9912A Single sweep measures both and NA R signals Because two ADC s are used simultaneously phase relationship is preserved Phase information is available to the user only in NA mode Details About Two Port Measurements Refer to the block diagram below showing the signal paths highlighted in color Figure 5 5 Signal Paths for Two Port CAT NA Measurements A4 RF BOARD SOURCE SYNTHESIZER 1 6 3 2 GHz Pep FRAC N SS 7 c ud VUL o moro La qot ATTEN w4 NA A J104 sl C nsn PATH 09 a E 9 LO SYNTHESIZER 1 6 3 2 GHz 7 VCO 9 me 2 LOGIC LL NEN E c W7 1 J105 30 MHz REF 1ST A PRE AMP wel sto Z Z wid 5 m AN aa a an S aa a ay A aa aea LE CQ RE M LL INPUT PATH n9912a rf blk two port 4 October 2008 The RF IN port is used as the second port Two sweeps are required for a measurement
40. Battery Description and Operation The main battery is an SBS Smart Battery System compliant pack of lithium ion cells Refer to Battery Disposal on page 1 7 for important information about replacing and disposing of this battery The nominal voltage of the battery is 10 8 volts and normally varies from 9 to 12 volts 5 18 Service Guide N9912 90003 RF Analyzer Theory of Operation N9912A Grounding and Power The battery has built in sensors a processor and control circuitry This is referred to as the Smart Battery circuitry The Smart Battery circuitry communicates battery condition and history information digitally via a digital Smart Batt Bus The Smart Battery circuitry is read only Both the battery charging circuit and the System Monitor read battery information over the Smart Batt Bus The battery temperature reported by the analyzer is based on a sensor inside the battery Temperature information is available over the Smart Batt Bus The thermistor connection T on the battery is not used The Smart Battery circuit may shut down the battery when the temperature is out of the acceptable range or when the battery charge is too low See the Working with the Lithium lon Battery section of the FieldFox User s Guide for additional information on e built in charge level gauge the battery information screen battery care Battery Information Screen Refer to the FieldFox User s Guide for information on how to access
41. D Cables 1 Perform the steps under Pre replacement Procedure on page 7 18 2 To replace the LCD shield a Remove the four screws item 1 that attach the LCD shield and discard them New screws are provided in the Repair and Re assembly Kit Lift the LCD shield off of the A2 LCD Install new gap pads on the new LCD shield in the locations shown Refer to Figure 7 15 and Figure 7 8 on page 7 12 for placement of gap pads Place the new LCD shield in position on the A2 LCD and secure it with four new screws item 1 These screws are provided in the Repair and Re assembly Kit 3 To replace the LCD cables and the A2 LCD Remove the LCD shield Refer to steps 2 a and 2 b of this procedure Disconnect the A2 LCD to A3 FPIB cable W13 at the A2 LCD If replacing only this cable 1 Disconnect the cable at both ends 2 Remove the cable from beneath the RPG cable W12 3 Route the new cable beneath the RPG cable as shown and re connect both ends 4 Bend the RPG cable toward the right side as shown 5 Skip to step 3 h Note the location of the adhesive tape over the connector on the A2 LCD to Ab system board cable W11 Remove the tape and disconnect the cable If replacing only this cable 1 Connect the new cable 2 Skip to step 3 h Remove the A2 LCD from the front case Place the new A2 LCD in position and re connect the cables Place a strip of adhesive tape over the LCD connector end of the A2 LCD to 5 system
42. J14 to A3 FPIB Cable doe NOTE J14 may be W14 Clamp incorrectly labeled as SA on cable Cable W4 Dowel 5 n9912_90003_721 W6 A4J104 Pin 7 32 Service Guide N9912 90003 RF Analyzer Repair and Replacement Procedures N9912A Removing and Replacing the Measurement Group Assemblies Replacing the RF Assembly Including the A4 RF Board 1 Separate the front and rear cases Refer to Separating the Front and Rear Cases on page 7 8 2 Remove all measurement group assemblies as one unit Refer to Removing All Measurement Group Assemblies as One Unit on page 7 25 3 Disconnect the flexible RF cables from the A4 RF board it is not necessary to disconnect the cables from the 5 system board Refer to Replacing the SOM Board and Flexible RF Cables on page 7 29 4 Remove the Ab system board Refer to Replacing the 5 System Board on page 7 31 5 Remove the BNC connector nut and washer from the old RF assembly and install them in the new RF assembly Note Cable W3 includes the BNC connector 6 Reinstall the Ab system board onto the new RF assembly Refer to Replacing the A5 System Board on page 7 31 7 Re connectthe flexible RF cables to the A4 RF board Refer to Replacing the SOM Board and Flexible RF Cables on page 7 29 8 Perform the steps under Post replacement Procedure on page 7 37 Service Guide N9912 90003 7 33 Repair and Replacement Procedures RF Analyzer Removing and Replacing the Measu
43. Keysight N991 2A RF Analyzer 2 MHz 4 GHz 2 MHz 6 GHz More Application Information and Pricing available at a og wz TestWorld 250 Technology Way sales testworld com Rocklin CA 95765 1 855 200 TEST 8378 Click to go www TestWorld com KEYSIGHT Service Guide TECHNOLOGIES NOTICE This document contains references to Agilent Technologies Agilent s former Test and Measurement business has become Keysight Technologies For more information goto www keysight com KEYSIGHT TECHNOLOGIES Warranty Statement THE MATERIAL CONTAINED IN THIS DOCUMENT IS PROVIDED AS IS AND IS SUBJECT TO BEING CHANGED WITHOUT NOTICE IN FUTURE EDITIONS FURTHER TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW KEYSIGHT DISCLAIMS ALL WARRANTIES EITHER EXPRESS OR IMPLIED WITH REGARD THIS MANUAL AND ANY INFORMATION CONTAINED HEREIN INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE KEYSIGHT SHALL NOT BE LIABLE FOR ERRORS OR FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES IN CONNECTION WITH THE FURNISHING USE OR PERFORMANCE OF THIS DOCUMENT OR ANY INFORMATION CONTAINED HEREIN SHOULD KEYSIGHT AND THE USER HAVE A SEPARATE WRITTEN AGREEMENT WITH WARRANTY TERMS COVERING THE MATERIAL IN THIS DOCUMENT THAT CONFLICT WITH THESE TERMS THE WARRANTY TERMS IN THE SEPARATE AGREEMENT WILL CONTROL DFARS Restricted Rights Notice If software is for us
44. OWER FRONT BATT NEG BATTERY SUPPLIES PANEL CHARGER INTERFACE V AND BOARD EXT DC MANAGER POWER O AC ADAPTER To Filters ADCs and MUX ANALOG ANALOG POWER POWER SUPPLY SUPPLIES LOAD SWITCHING TO A4 RF BOARD n9912a system blk 24 August 2009 Service Guide N9912 90003 5 15 Theory of Operation RF Analyzer Measurement Group N9912A A6 SOM Board The A6 SOM System on Module board plugs directly into the A5 system board as a daughter board and contains the CPU 64MB of flash ROM 128 MB of RAM and 1 0 interface The interfaces on the SOM are UART to the System Monitor on the Ab system board LCDinterface Left and right audio outputs SDcard bus USB host interface Interface to USB hub LANinterface 10 100 base T General purpose interface lines The A6 SOM board is powered by the 3 3 volt digital supply Licenses which enable instrument options are stored in the A6 SOM flash ROM Main Battery The battery is a rechargeable 10 8 V lithium ion type Refer to Battery Disposal on page 1 7 for important information about replacing and disposing of this battery Refer to Battery Related Information on page 5 18 for details on the main battery 5 16 Service Guide N9912 90003 RF Analyzer Theory of Operation N9912A Grounding and Power Grounding and Power Grounding Each printed circuit board has a single ground plane The ground planes on the A4 RF board and 5 s
45. RF Analyzer Removing and Replacing the Case Group Parts N9912A Replacing the Front Case including the A1 Keypad 1 2 Separate the front and rear cases See Separating the Front and Rear Cases Remove the measurement group assemblies RF top panel assembly A4 RF board A5 system board and SOM board as one unit with the 1 0 panel attached Refer to Removing and Replacing the Measurement Group Assemblies on page 7 25 Remove the front panel group assemblies A2 LCD A3 front panel interface board and RPG Refer to Removing and Replacing the Front Panel Group Assemblies on page 7 18 Figure 7 10 Replacing the Front Case Model Number Nameplate Overlay 6 Hole Plugs Hole Plug front view n9912 90003 710 Carefully remove the serial number label from the inside bottom of the old front case and apply the label to the new front case Choose the appropriate model number nameplate overlay for your analyzer remove the protective backing to expose the adhesive and adhere it in the location shown Remove the dowel pins item 5 from the old front case and install them in the new case The other two dowel pins should already be installed in the case Make sure that the gaskets item 6 are all in place in the grooves that there are no gaps and that they are not damaged in any way Refer to Removing and Replacing the Front Panel Group Assemblies on page 7 18 to reinsta
46. Service Guide N9912 90003 7 29 Repair and Replacement Procedures RF Analyzer Removing and Replacing the Measurement Group Assemblies N9912A Figure 7 21 Replacing the A6 SOM Board and Flexible RF Cables Enlarged Side View Cable WS A4J102 to A5J18 Cable W6 Connector marked with red A4J101 to A5J1 4 Single Coaxial Cable Replacement Assembly Cable W4 A4J104 to A5J19 Cable Signals We BA 44J105 to A5J20 WA SA IF g W5 NA R IF CO W6 NA A IF UY WZ 30 MHz ref No slack 4 places Cable Clamp 2 t on cable Us en W6 oar I O Side TCXO Panel Chip Connector marked with red J14 on AS System board Cable W4 NOTE J14 may be 0104 on A4 RF board incorrectly labeled as SA n9912 90003 720 W6 7 30 Service Guide N9912 90003 RF Analyzer Repair and Replacement Procedures N9912A Removing and Replacing the Measurement Group Assemblies Replacing the A5 System Board 1 2 12 13 16 17 18 Separate the front and rear cases See Separating the Front and Rear Cases on page 7 8 Remove all measurement group assemblies as one unit Refer to Removing All Measurement Group Assemblies as One Unit on page 7 25 Remove the 1 0 side panel Refer to Replacing the 1 0 Side Panel Doors and Gasket on page 7 12 Remove the A6 SOM board and flexible RF cables Refer to Replacing the SOM Board and Flexible RF Cables on page 7 29 Re
47. The actual voltage determines the brightness of the backlight Two control lines from the Ab system board control on off and intensity functions These control lines are driven by the system monitor microcontroller on the A5 system board Speaker and Headphones The speaker is located on the A3 front panel interface board Left and right audio signals from the A6 SOM board go to the headphone jack on the 5 system board These signals are then combined on the 5 system board to create a single mono signal for the speaker An amplifier on the A3 front panel interface board drives the speaker Plugging in the headphones disables the speaker output Digital Power Supplies Digital power supplies on the A3 front panel interface board are driven by the Unreg DC voltage from the A5 Service Guide N9912 90003 5 5 Theory of Operation RF Analyzer Front Panel Group N9912A system board The 5 volts produced is used on the front panel interface board and the Ab system board The 3 5 volts produced is used on the A3 front panel interface board the Ab system board and the A6 SOM board Both supplies are either on or off together except for power supply sequencing and are controlled by the System Monitor Microcontroller on the Ab system board A2 LCD Assembly The A2 LCD assembly contains a 6 5 inch 640 x 480 TFT color LCD with associated drive circuitry and backlight inverter The LCD backlight is created by LED s connected in parallel s
48. about 7 4 Service Guide N9912 90003 Index case group procedure 7 6 CPU board 7 25 front panel group assemblies 7 18 LCD shield 7 18 main battery 7 5 measurement group assemblies 7 25 RF assembly 7 25 RF connectors 7 25 RF top assembly 7 25 RPG 7 18 RPG knob 7 18 RTC battery 7 18 replacement sequence 4 3 returning to customer checklist 3 6 RF assembly removal and replacement 7 25 RF board operation 5 7 RF connectors removal and replacement 7 25 RF top assembly removal and replacement 7 25 RPG manual check 7 38 removal and replacement 7 18 RPG knob removal and replacement 7 18 RTC battery removal and replacement 7 18 safety considerations 1 3 earth ground 1 3 symbols 1 3 screen temp 5 24 SD card used to install firmware 7 38 service battery maintenance 8 7 cleaning the display 8 7 contacting Keysight 2 5 erase user data utility 8 3 options 2 4 procedures caution about 7 3 post repair 7 37 warnings about 7 3 related user operations 8 3 static safety parts part numbers 6 14 tools part numbers 6 14 view current firmware revision 8 3 view currently installed options 8 3 view temperature readings 8 3 view the error log 8 3 warranty standard 2 4 three year return to Keysight 2 4 service test equipment 3 5 shipment for service or repair 2 5 smart power management operation 5 17 SOM board operation 5 16 standards compliant calib
49. ason you must order a Repair and Re assembly Kit See Miscellaneous Parts on page 6 14 Service Guide N9912 90003 RF Analyzer Replaceable Parts N9912A Replaceable Parts Listings Figure 6 2 Front Panel Group Exploded View Front View 4 Rear View n9912_90003_602 Service Guide N9912 90003 6 7 Replaceable Parts Replaceable Parts Listings Measurement Group RF Analyzer N9912A Reference Designator Part Number Oty Description Replacement Assemblies RF Assembly Includes RF board System gasket kit assembly 2 gaskets 1 Polyiron mixer house w pad 2 RFI wafer gasket qty 2 3 Insulator qty 2 4 Polyiron front end 5 Polyiron pre amp 6 Polyiron input 7 QS N9912 60002 1 Shield bottom RF 8 y Shield top RF 9 Cable W2 semi rigid RF IN SA port 10 Cable W1 semi rigid RF OUT NA port 11 Gap pad 6 mm square 12 RFI O ring qty 2 13 RFI strip qty 4 14 Adapter coaxial straight female type N to female 3 5 mm qty 2 15 Screw machine w crest cup washer pan head M3 0 x 12 mm qty 30 16 Screw machine w crest cup washer pan head M3 0 x 8 mm qty 4 17 System System Board Assembly Includes Board N9912 60004 System gasket kit assembly 2 gaskets 1 Assembly Clamp stick on qty 2 18 Coax Coax Cable Assembly Includes Cable N9912 60029 1 Cable W4 and W6 RF flexible qty 2 19 Assembly Spiral wrap plast
50. assemblies in this instrument are very susceptible to damage from electrostatic discharge ESD Perform the following procedures only at a static safe workstation and wear a grounded wrist strap This is important If not properly protected against electrostatic discharge can seriously damage your analyzer resulting in costly repair To reduce the chance of electrostatic discharge follow all of the recommendations outlined in Electrostatic Discharge Protection on page 1 5 for all of the procedures in this chapter Service Guide N9912 90003 7 3 Repair and Replacement Procedures Assembly Replacement Sequence Assembly Replacement Sequence RF Analyzer N9912A The following steps show the sequence that you should follow to replace an assembly in the network analyzer Step 1 Identify the faulty group Begin with Chapter 4 Troubleshooting Step 2 Order a replacement assembly Refer to Chapter 6 Replaceable Parts Step 3 Replace the faulty assembly and determine what adjustments are necessary Refer to Post Repair Procedures in this chapter Step 4 Perform the necessary adjustments Refer to Chapter 3 Tests and Adjustments Step 5 Perform the necessary performance tests Refer to Chapter 3 Tests and Adjustments Removal and Replacement Procedures Table 7 1 List of Procedures Reference Designator or Name Assembly Description Locat
51. be disposed of dispose of it in accordance with your country s requirements If required you may return the battery to Keysight Technologies for disposal Refer to Contacting Keysight on page 2 5 for assistance DO NOT THROW BATTERIES AWAY BUT COLLECT AS SMALL CHEMICAL WASTE For instructions on removing and replacing the primary power battery refer to Removing and Replacing the Main Battery on page 7 5 For instructions on removing and replacing the RTC real time clock battery located on the A3 front panel interface board refer to Replacing the A3 Front Panel Interface Board FPIB on page 7 22 Service Guide N9912 90003 1 7 Safety and Regulatory Information RF Analyzer Regulatory Information N9912A 1 8 Service Guide N9912 90003 2 General Product Information Service Guide N9912 90003 2 1 General Product Information RF Analyzer Information in This Chapter N9912A Information in This Chapter Chapter Two at a Glance Section Title Summary of Content Start Page Cleaning instructions for the external surfaces of your analyzer Maintenance Page 2 3 Information about electrical maintenance of your analyzer A list of the options available for the microwave Page 2 3 network analyzers The Internet address URL for Keysight assistance Service and support options available Keysight Support Services and Calibration options available Page 2 4 Assistance Im
52. board cable W11 in the same location as the old strip and as shown A new strip of adhesive tape is provided in the Repair and Re assembly Kit Connect cable W13 to the A2 LCD There are two identical connectors CN3 and CN4 near the connector for cable W13 A strip of adhesive tape should cover each connector as shown in Figure 7 15 If not apply tape strips by cutting a strip of adhesive tape provided in half and applying one half to each connector as shown in Figure 7 15 Press down firmly on the tape to conform it to the contours of the connectors and to ensure proper adhesion The strip of adhesive tape is part of the N9912 60027 Repair and Re assembly Kit Reinstall the LCD shield with four new screws provided in the Repair and Re assembly Kit Refer to step Step d on page 7 20 of this procedure 4 Perform the steps under Post replacement Procedure on page 7 24 7 20 Service Guide N9912 90003 RF Analyzer Repair and Replacement Procedures N9912A Removing and Replacing the Front Panel Group Assemblies Figure 7 15 Replacing the A2 LCD the LCD Shield and LCD Cables n ec Roy ALD duce A2 gri 3 Adhesive FPIB Cable W13 A2 LCD 1 to AS System Board Cable RPG Cable w11 W12 A3 Front Panel Interface Board FPIB The LCD shield was removed for the photo below CN3 and CN4 provide power for the LCD backlight Adhesive Adhesive Tape Tape CN3 CN4
53. cing the Case Group Parts N9912A Removing and Replacing the Case Group Parts Tools Required T 8TORX driver set to 6 in Ib T 10 TORX driver set to 9 in Ib Isopropyl alcohol Use only in a well ventilated area Repair and Re assembly Kit Refer to Miscellaneous Parts on page 6 14 WARNING Before beginning any repair disconnect the power cord Replacing the Kickstand Hinge Cover and Hinge 1 Remove and discard the four screws item 1 from the kickstand hinge cover New screws are provided in the Repair and Re assembly Kit Figure 7 2 Replacing the Kickstand and Hinge Cover fA Nw d LEN QO 1 Lo e gt places d TK Kickstand Hinge Cover W 7 bf 2 0 n9912 90003 702 1 6 Service Guide N9912 90003 RF Analyzer Repair and Replacement Procedures N9912A Removing and Replacing the Case Group Parts 2 To replace the entire kickstand assembly a Lift the kickstand assembly off of the rear case and discard it b Place the new kickstand assembly on the rear case c Place the new hinge cover in position and secure it with four new screws A new hinge cover and new screws are provided in the Repair and Re assembly Kit 3 To replace the hinge cover a Position the new hinge cover in place and install four new screws New screws are provided in the Repair and Re assembly Kit
54. de N9912 90003 7 17 Repair and Replacement Procedures RF Analyzer Removing and Replacing the Front Panel Group Assemblies N9912A Removing and Replacing the Front Panel Group Assemblies Tools Required T 8TORX driver set to 6 in Ib T 10 TORX driver set to 9 in Ib e 7 16 inch hex nut wrench or nut driver set to 9 in Ib Repair and Re assembly Kit Refer to Miscellaneous Parts on page 6 14 Soldering tool Required only for RTC battery replacement WARNING Before beginning any repair disconnect the power cord Pre replacement Procedure 1 Separate the front and rear cases Refer to Separating the Front and Rear Cases on page 7 8 2 Remove the measurement group assemblies RF top panel A4 RF board Ab system board and A6 SOM board as one unit with the 1 0 panel attached Refer to Removing and Replacing the Measurement Group Assemblies on page 7 25 Replacing the RPG and RPG Knob 1 Perform the steps under Pre replacement Procedure on page 7 18 2 Remove the two hole plugs from the back side of the front case next to the RPG 3 Toreplace the RPG knob a Insert a round shaft such as a screwdriver shaft into the exposed holes and push the RPG knob off of the RPG shaft to the front side of the front case b Install a new knob by aligning the D shaped detent in the knob with the D shape on the shaft and push the knob into position 4 Toreplace the RPG a Remove the RPG knob Refer to step 3 a of
55. e enabled via licenses additional hardware is not required Functional Groups of the Analyzer The operation of the analyzer can be separated into two major functional groups Each group consists of assemblies that perform distinct functions Some of the assemblies are related to more than one group and both groups to some extent are interrelated and affect each other s performance The major functional groups are Front Panel Group Measurement Group Front Panel Group The front panel group consists of the following A2LCD Assembly Front Panel Interface Board Measurement Group The measurement group consists of the following RF Board Ab System Board A6 SOM Board Main Battery Service Guide N9912 90003 5 3 Theory of Operation RF Analyzer Analyzer System Operation N9912A Figure 5 1 Overall Block Diagram EXT TRIG wa EXT REF A5 SYSTEM BOARD A4 RF BOARD J105 NA A J101 A3 FRONT PANEL SPEAKER INTERFACE BOARD KEYPAD LED S KEYPAD MICROCONTROLLER AND POWER AC ADAPTER POWER ON OFF ANAGEMENT AND ANALOG BUTTON POWER SUPPLIES AND LED DC DIGITAL POWER BATTERY 10 8 VDC SUPPLIES L 2 LCD ASSEMBLY n9912a overall blk 24 August 2009 5 4 Service Guide N9912 90003 RF Analyzer Theory of Operation N9912A Front Panel Group Front Panel Group The front panel group consists of the following assemblies Front Panel
56. e in the performance of a U S Government prime contract or subcontract Software is delivered and licensed as Commercial computer software as defined in DFAR 252 227 7014 June 1995 or as a commercial item as defined in FAR 2 101 a or as Restricted computer software as defined in FAR 52 227 19 June 1987 or any equivalent agency regulation or contract clause Use duplication or disclosure of Software is subject to Keysight Technologies standard commercial license terms and non DOD Departments and Agencies of the U S Government will receive no greater than Restricted Rights as defined in FAR 52 227 19 c 1 2 June 1987 U S Government users will receive no greater than Limited Rights as defined in FAR 52 227 14 June 1987 or DFAR 252 227 7015 b 2 November 1995 as applicable in any technical data Certification Keysight Technologies certifies that this product met its published specifications at the time of shipment from the factory Keysight Technologies further certifies that its calibration measurements are traceable to the United States National Institute of Standards and Technology to the extent allowed by the Institute s calibration facility and to the calibration facilities of other International Standards Organization members ii Service Guide N9912 90003 Assistance Product maintenance agreements and other customer assistance agreements are available for Keysight Technologies products For informa
57. e listed under Miscellaneous Parts on page 6 14 Service Guide N9912 90003 6 5 Replaceable Parts Replaceable Parts Listings Front Panel Group RF Analyzer N9912A Reference Designator Part Number Oty Description Replacement Assemblies A3 Front Panel Board Assembly N9912 60003 Front Panel Board Assembly Includes A3 front panel interface board Separately Replaceable Individual Parts and Assemblies Keypad assembly Part of Front Enclosure Assembly and not separately replaceable see Case ai Group on page 6 11 A2 2090 0968 1 LCD assembly 6 5 inch TFT VGA 1 LCD lens filter Part of Front Enclosure Assembly and not separately replaceable see Case Group on page 6 11 2 N9912 00001 1 LCD shield bracket 3 0515 1521 13 Screw machine 90 deg flat head M3 0 x 5 mm 4 1990 3613 1 RPG Rotary Pulse Generator Includes cable W12 nut and washer 5 W1312 40066 1 RPG knob 6 N9912 60017 1 Cable W13 A2 LCD to A3 front panel interface board 7 N9912 60006 1 Cable W14 ribbon A3 front panel interface board to A5 system board 8 N9912 60016 1 Cable W11 A2 LCD to Ab system board 8 N9912 20035 1 pad LCD shield 10 N9912 20038 Gap pad LCD shield 11 1420 0536 Battery Lithium ion For Real Time Clock RTC backup 1 Each time the N9912A case is opened for any re
58. econd Each ADC may be put into a low power mode when not active Temperature Sensors The SB1 Temp Sensor is located on the A4 RF board side of the Ab system board near the headphone jack J3 The SB2 Temp Sensor is on the A4 RF board side of the system board near the edge of the board against the battery compartment This temperature sensor is not under a shield Audio Output Jack When headphones are plugged into the audio output jack the internal speaker is disabled LAN Connector The LAN connector supports the LAN interface on the A6 SOM board See LAN Interface on page 5 29 for more details Service Guide N9912 90003 5 13 Theory of Operation RF Analyzer Measurement Group N9912A SOM Connector Refer to A6 SOM Board on page 5 16 for information on SOM System on Module functions 5 14 Service Guide N9912 90003 RF Analyzer Theory of Operation N9912A Measurement Group Figure 5 3 Simplified RF Block Diagram EXT TRIG EXT REF ws J16 A5 SYSTEM BOARD 30 MHz w J20 30 MHz E NA R Ws J18 QD FILTER TO FROM Lr AA RF NA A BOARD W6E 4 30 MHz TIME QD FILTER BASE MUX ADC WAT 2 FILTER lt n usa T0 a USB lt LAN LAN Mini SD SD CARD SERIAL BUS A TO FROM A4 RF BOARD SERIAL BUS SYSTEM SMART BATT BUS MONITOR MICROCONTROLLER TO FROM DIGITAL P
59. es interpolation When choosing the Connector Type choose the characteristics that correspond to the cal kit you will use For the standard FieldFox Tee cal kit part number 1250 3607 choose Type N M Do not leave cal standards connected to the RF IN or RF OUT ports for more than three minutes Heat in the port connectors may affect the accuracy of the standards Table 5 2 Cal Status Indicators Indicator Meaning Additional Indicators Cal ON Preset factory calibration is active mteiolaton active Measurement conditions have changed eee interpolation active Cal ON Q QuickCal calibration is active Measurement conditions have changed interpolation active Cal ON U D S L calibration is active Measurement conditions have changed Cal OFF Calibration is inactive No calibration available to activate for this Cal OFF measurement One Port Calibration One port calibration applies only to 1 port measurements in CAT and NA modes When the analyzer is adjusted at the factory or during annual calibration a preset calibration is stored in the analyzer The preset calibration covers the full frequency range of the analyzer The preset calibration is active whenever Cal ON is displayed on the left side of the screen Presetting the analyzer activates the preset calibration The preset calibration provides very good measurement performance at the RF OUT connector
60. eypad through the holes in the A3 FPIB Make sure that all nine of the rubber nubs are fully extended on the back side of the A3 FPIB Secure the A3 FPIB to the front case with nine new screws item 3 provided in the Repair and Re assembly Kit Re connect theA2 LCD to FPIB cable W13 to the A3 FPIB connector as indicated Route the cable as shown Re connect the RPG cable W12 to the A3 FPIB connector as indicated with the A2 LCD to A3 FPIB cable W13 passing beneath it as shown Bend the RPG cable toward the right side as shown Place the LCD shield back in position on the A2 LCD Make sure that the A2 LCD to A3 FPIB cable W13 is routed between not under the shield gaskets Secure the shield with four new screws item 2 provided in the Repair and Re assembly Kit Perform the steps under Post replacement Procedure on page 7 24 7 22 Service Guide N9912 90003 RF Analyzer Repair and Replacement Procedures N9912A Removing and Replacing the Front Panel Group Assemblies Figure 7 16 Replacing the A3 Front Panel Interface Board A2 LCD Display i jl DEP Orr ues e 3 Poe 1 places ks LJ Front UG A 19 Panel lt a Interface Board FPIB RTC Battery Dispose of properly Keypad Nubs A3 Front Panel Interface Board FPIB n9912_90003_716 Service Guide N9912 90003 7 23 Repair and Replacement Procedures RF
61. eysight for calibration Refer to Shipping Your Analyzer to Keysight for Service or Repair Contacting Keysight Assistance with test and measurements needs and information on finding a local Keysight office are available on the Web at http www keysight com find assist If you do not have access to the Internet please contact your Keysight field engineer NOTE In any correspondence or telephone conversation refer to the Keysight product by its model number and full serial number With this information the Keysight representative can determine whether your product is still within its warranty period Shipping Your Analyzer to Keysight for Service or Repair IMPORTANT Keysight Technologies reserves the right to reformat or replace the internal hard disk drive in your analyzer as part of its repair This will erase all user information stored on the hard disk It is imperative therefore that you make a backup copy of your critical test data located on the analyzer s hard disk before shipping it to Keysight for repair If you wish to send your network analyzer to Keysight Technologies for service or repair nclude a complete description of the service requested or of the failure and a description of any failed test and any error message Ship the analyzer using the original or comparable antistatic packaging materials Contact Keysight for instructions on where to ship your analyzer Refer to Contacting Keysight on page
62. f the instrument A brief description of why options need to be re installed This information will help Keysight identify recurring problems that may need special attention 2 Within two working days you will receive an email response with a license file attached 3 Copy the license file to the root of a USB flash drive Follow the appropriate instructions in the N9912A Upgrade Installation Instructions N9912 90005 to install the licenses These instructions are available by searching for N9912 90005 on the Web at www keysight com Additional Information About Options For information on acquiring additional options go to www keysight com find fieldfox2 and follow the Upgrades available for FieldFox N9912A link There is an installation note associated with each option upgrade that provides detailed instructions Some combinations of options are not valid see the web information for details Service Guide N9912 90003 8 5 General Purpose Maintenance and Service Procedures Firmware Upgrades Firmware Upgrades To Check the Current Firmware Revision Press System 7 Press Service Diagnostics Press System Information The current firmware version is indicated on the Firmware Release line RF Analyzer N9912A For information on upgrading FieldFox firmware go to www keysight com find fieldfox2 If the firmware upgrade process is interrupted memory contents in the instrument may become corrupted If a prob
63. fer also to Enlarged Side View in illustration Note which cable is connected to which pc board connector to aid in reinstallation Disconnect cable W3 from the A5 system board Remove four screws item 4 from the system board shield and remove the shield Discard the screws new ones are provided in the Repair and Re assembly Kit Remove six screws item 5 from the A5 system board lift it up from the RF bottom shield and unplug it from the A4 RF board connector Discard the screws new ones are provided in the Repair and Re assembly Kit Remove the waffle gasket from the RF bottom shield and discard it A new gasket is provided in the Repair and Re assembly Kit Manipulate the new waffle gasket by hand to eliminate curling and install it on the RF bottom shield using the three dowel pins for alignment It is not necessary that the gasket be completely flat just enough to remain in position while installing the new A5 system board Plug in the new A5 system board to the A4 RF board over the new gasket and aligned with the three dowel pins in the RF bottom shield Position a new waffle gasket from the Repair and Re assembly Kit for the system board top shield on the 5 system board using the two dowel pins for alignment Manipulate this gasket by hand to flatten it if necessary Reinstall the system board top shield over the gasket and aligned with the dowel pins Hand tighten four new screws item 4 to secure the system
64. hapter This chapter identifies the replaceable parts for the N9912A RF analyzer includes several tables and illustrations to assist you in identifying the correct part for your analyzer contains ordering information for new assemblies and rebuilt exchange assemblies Chapter Six at a Glance Section Title Summary of Content Start Page How to order a replaceable part from Keysight Ordering Information Tachnolugies Page 6 3 hssembly Replacement Breaedure The correct sequence for determining the failure of and replacing a defective assembly Paris Tables with illustrations that list all replaceable parts in BS your analyzer 6 2 Service Guide N9912 90003 RF Analyzer Replaceable Parts N9912A Ordering Information Ordering Information To order a part listed in the replaceable parts lists include the part number indicate the quantity required Contact Keysight Technologies for instructions on where to send the order Refer to Contacting Keysight on page 2 5 To order a part that is not listed in the replaceable parts lists include the instrument model number and complete instrument serial number include the description and function of the part indicate the quantity required Contact Keysight Technologies for instructions on where to send the order Refer to Contacting Keysight on page 2 5 Service Guide N9912 90003 6 3 Replaceable Part
65. harge the battery to 80 or higher Operational Check 1 Preset the instrument press Preset gt Preset Leave the RF OUT connector open Press Scale Amptd gt Ref Pos gt 2 gt Enter The trace should be within 5 dB of 0 00 dB Connect a known good load to the RF OUT connector The trace should be below 30 dB Sl ge seams S Press Measure gt More If an Insertion Loss softkey is displayed then do the following 8 Press Insertion Loss b Connect a short cable between the RF OUT and RF IN connectors c The trace should be within 15 dB of 0 00 dB 8 Press Mode If an SA softkey is displayed then do the following a Press SA b Leave the RF IN connector open c Between 30 MHz and 5 GHz the trace should be below 45 dBm d Between 5 GHz and 6 GHz the trace should be below 35 dBm NOTE If the operational check fails allow the instrument to warm up for 15 minutes and try again 3 6 Service Guide N9912 90003 RF Analyzer Tests and Adjustments N9912A Performance Tests Keysight N7841A Software Package Performance Tests Keysight N7841A Software Package The performance tests section of the Keysight N7841A software package verifies the electrical performance of your N9912A analyzer The software automatically configures your analyzer to execute the performance tests The N7841A software package is not included with the analyzer it must be ordered separately It can be downloaded from the Inte
66. hell of the test port or cable connector briefly always ground the center conductor of a test cable before making a connection to the analyzer test port or other static sensitive device This can be done as follows 1 Connecta short from your calibration kit to one end of the cable to short the center conductor to the outer conductor 2 While wearing a grounded wrist strap grasp the outer shell of the cable connector 3 Connectthe other end of the cable to the test port and remove the short from the cable Figure 1 1 shows a typical ESD protection setup using a grounded mat and wrist strap Refer to ESD Supplies on page 6 14 for part numbers Figure 1 1 ESD Protection Setup lt gt gt Wrist Strap A 3 Wire line power cord with proper connection to ground must be used for ESD protection Anti Static Mat esd_setup Service Guide N9912 90003 1 5 Safety and Regulatory Information RF Analyzer Regulatory Information N9912A Regulatory Information This section contains information that is required by various government regulatory agencies Instrument Markings The instruction documentation symbol The product is marked with this symbol when it is necessary for the user to refer to the instructions in the documentation This symbol indicates separate collection for electrical and electronic equipment mandated under EU law as of August 13 2005 All electric and electronic equipment are requ
67. high See DUT Warmup in the Getting Started section of the N7841A help file for usage instructions Generic small office fan of approximately six inches in diameter is sufficient Type N male cal kit Tee cal kit part number 1250 3607 is recommended This matches the default cal kit definition stored in the analyzer Cal kits 85032E F or 85054B D may be substituted Mini SD flash card Required to re load firmware onto the SOM board A mini sized Secure Digital SD flash memory card is between standard and micro sizes The memory size must be at least 64 MB and not greater than 2 GB This card is not available from Keysight To identify a supplier search the Web for mini sd card Stereo headphones or ear buds May be used to troubleshoot sound output if there is a problem with the internal speaker Service Guide N9912 90003 3 5 Tests and Adjustments RF Analyzer Before Returning an Instrument to a Customer N9912A Before Returning an Instrument to a Customer When finished servicing an N9912A analyzer perform the following before returning the unit to the customer Set the Display Colors to Indoors and the display Brightness to 80 via Service 7 gt Display Perform an Operational Check as described in the following section Connectand disconnect the external battery charger while the N9912A is operating and confirm that the power cord icon is displayed appropriately at the top of the display C
68. ic 20 RF Top Panel Assembly Includes Panel RF machined 21 Connector cover tethered cap for type N connector qty 2 22 Overlay RF 23 Top Panel N9912 60021 1 Gasket RF 24 Assembly Cable W3 RF coax with BNC connector EXT TRIG EXT REF connector 27 Washer internal tooth 15 32 inch 28 Nut specialty 15 32 inch 32 thread 29 Separately Replaceable Individual Parts and Assemblies 1150 8023 1 SOM Board 532 MHz processor 128 MB SDRAM 1 N9912 60019 1 System gasket assembly 2 gaskets for A5 system board 4 N9912 20033 1 Insulator w pad 10 N9912 20010 1 Cable W2 semi rigid RF IN SA port 11 N9912 20009 1 Cable W1 semi rigid RF OUT NA port 13 8160 0963 2 RFI O ring 15 1250 2180 2 Adapter coaxial straight female type N to female 3 5 mm 17 0515 0372 4 Screw machine w crest cup washer pan head M3 0x 8 mm 22 W1312 40069 2 Connector cover tethered cap for type N connector 25 N9912 20116 1 System board top shield 25 26 N9912 20028 1 Pad system board top shield to A2 LCD 27 8121 0964 1 Cable W3 RF coax with BNC connector EXT TRIG EXT REF connector 28 2190 0102 1 Washer internal tooth 15 32 inch 23 0590 1251 1 Nut specialty 15 32 inch 32 thread 30 8121 1614 2 Cable W5 and W7 RF coax flexible 31 0515 0374 4 Screw machine w crest cup washer pan head M3 0 x 10 mm 1 Each
69. ient temperature Service Guide N9912 90003 5 19 Theory of Operation RF Analyzer Operation in Modes N9912A Operation in Modes The FieldFox User s Guide describes the various modes of operation and describes the user interface for each mode The following information describes how the hardware is used in the various modes to make measurements There are four basic modes of operation e CAT Cable and Antenna Test e NA Network Analyzer SA Spectrum Analyzer e PM Power Meter CAT and NA modes have similar capabilities but are separate modes of operation Additional modes of operation may be created as new firmware is developed The four basic modes listed above represent how the hardware may be used to make basic measurements Additional modes will provide customized user interfaces but will not change how the basic measurements are performed The following table indicates port functionality for each mode of operation and the required options See the Service Related User Operations section of Chapter 8 for more details Table 5 1 Port Function by Mode Measurement RF OUT RF IN Required Mode Port Port Option s CAT None One Port Input Output Inactive standard CAT Insertion Loss Input n be Input Output Inactive 303 NA 21 Output Input 110 and 303 SA Inactive Input 230 or 231 Power Meter Inactive Inactive 302 For a given mode the analyzer remembers the
70. ing normal operation as each SA measurement is taken the current RF2 temperature reading is compared tot he temperature stored for the Frequency Response adjustment A delta temperature is calculated Each SA measurement is adjusted to compensated for the delta temperature The internal temperature of the unit is critical when executing the TME based software for tests and adjustments See the TME help for detailed information Under typical bench top indoor conditions the internal temperature of the unit will be about 20 xC above ambient once the internal temperature has stabilized It will typically take 60 to 90 minutes for the internal temperature to stabilize when a cold unit is turned on 5 24 Service Guide N9912 90003 RF Analyzer Theory of Operation N9912A User Calibration in CAT and NA Modes User Calibration in CAT and NA Modes There are two types of calibrations for the CAT and NA modes one port and two port See the FieldFox User s Guide Calibration for CAT and NA Modes section for specific instructions for performing these calibrations A calibration performed in CAT mode will be applied in NA mode and vice versa When a user calibration is performed the full frequency range of the analyzer is calibrated even though the current state of the analyzer may be less than the full range This allows a calibration to be interpolated beyond the frequencies set at the time of calibration an asterisk on the display indicat
71. ion Case parts All enclosure case parts Page 7 6 RPG RPG part of front panel group Page 7 18 RPG knob RPG knob part of front panel group Page 7 18 RTC Backup battery for real time clock Soldered onto the A3 front panel battery interface board Paga me Main battery Primary power battery Page 7 5 A1 Keypad Page 7 22 A2 LCD Page 7 20 A3 Front panel interface board Page 7 22 A4 RF board Page 7 25 A5 System board Page 7 25 A6 SOM board Page 7 25 7 4 Service Guide N9912 90003 RF Analyzer Repair and Replacement Procedures N9912A Removing and Replacing the Main Battery Removing and Replacing the Main Battery Tools Required None IMPORTANT Refer to Battery Disposal on page 1 7 for important instructions on disposing of the old battery Replacing the Main Battery 1 Disconnect the power cord 2 Remove the battery compartment door by pushing in on the detent and then sliding the door downwards 3 Note the orientation of the battery for installation of the replacement 4 Remove the old battery and install the new battery in the battery compartment 5 Reinstall the battery compartment door by aligning it in position and then sliding it upwards until an audible click is heard Figure 7 1 Replacing the Main Battery Detent Push here and slide downwards Compartment Door n9912_90003_701 Service Guide N9912 90003 7 5 Repair and Replacement Procedures RF Analyzer Removing and Repla
72. ired to be separated from normal waste for disposal Reference WEEE Directive 2002 96 EC The CE mark is a registered trademark of the European Community If accompanied by a year it is when the design was proven The CSA mark is a registered trademark of the CSA International This mark designates the product is an Industrial Scientific and Medical Group 1 Class A product reference CISPR 11 Clause 5 This is a marking to indicate product compliance with the Canadian Interference Causing Equipment Standard ICES 001 The instrument has been designed to meet the requirements of IP 2 0 for egress and operational environment The RCM mark is a registered trademark of the Australian Communications and Media Authority Indicates the time period during which no hazardous or toxic substance elements are expected to leak or deteriorate during normal use Forty years is the expected useful life of the product This symbol on all primary or secondary packaging indicates compliance to China standard GB 18455 2001 South Korean Certification KC mark includes the marking s identifier code which follows the format 51 77777777777777 or 777777777777 Service Guide N9912 90003 RF Analyzer Safety and Regulatory Information N9912A Regulatory Information Battery Disposal If the either the primary power battery or the RTC real time clock battery on the A3 front panel interface board needs to
73. is not included with the analyzer it must be ordered separately It can be downloaded from the Internet and a license purchased on line or it can be ordered on a CD ROM Go to www keysight com find calibrationsoftware for further information These adjustments consist of Three general adjustments that are used to adjust the general functions of the analyzer Seven adjustments specifically for the SA spectrum analyzer functions Total adjustment time will vary from 1 to 80 minutes depending upon options installed If multiple adjustments are to be performed perform them in the order listed by the N7841A software Details for these adjustments and recommended troubleshooting information can be found in the N7841A help file General Adjustments Total time for these adjustments is six minutes Frequency Accuracy ADC Overload Adjustment Error Terms NA Adjustment This adjustment is part of the Error Terms Test see Performance Tests Keysight N7841A Software Package on page 3 7 and should be performed every 12 months It refreshes the definition of the preset calibration Spectrum Analyzer Specific Adjustments Total time for these adjustments is 75 minutes IF Frequency Response Adjustment Absolute Amplitude Adjustment Frequency Response with Preamp On Adjustment Frequency Response with Preamp Off Adjustment Attenuator Slope Adjustment IF Offset Adjustment Spur
74. lacement 7 25 CSA mark 1 6 display illustrated 6 5 operation 5 6 parts list 6 5 removal and replacement 7 18 documentation optional 1 1 part numbers 6 14 standard 1 iii E earth ground 1 3 electrostatic discharge See ESD equipment for service 3 5 erase user data utility 5 27 error log 5 27 ESD protection 1 5 3 3 4 3 7 3 supplies part numbers 6 14 F firmware check current revision of 8 6 erase user data utility 5 27 error log 5 27 general description 5 27 install from SD card 7 38 operational files 5 27 upgrades 5 27 upgrading 8 6 user accessible files 5 27 front panel replaceable parts illustrated 6 5 part numbers 6 5 front panel group operation 5 5 troubleshooting 4 7 front panel group assemblies removal and replacement 7 18 front panel interface board illustrated 6 5 operation 5 5 part number 6 5 removal and replacement 7 18 functional groups 5 3 G general safety considerations 1 3 ground safety earth 1 3 grounding operation 5 17 instruction documentation symbol 1 6 instrument markings 1 6 instrument serial number compare 7 38 load 7 38 ISM1 A mark 1 6 ISO 17025 standards compliant calibration Option 1A7 2 4 K keyboard manual check 7 38 keypad illustrated 6 5 Service Guide N9912 90003 Index 1 Index part number 6 5 removal and replacement 7 18 Keysight contacting 2 5 support 2 4 kickstand removal and
75. lem is suspected consider doing a fresh installation of the firmware Follow the process under Install Firmware from SD Card near the end of Chapter 7 See the Firmware Related Information section of Chapter 5 for details on what happens during the firmware update process Service Guide N9912 90003 RF Analyzer General Purpose Maintenance and Service Procedures N9912A Miscellaneous Service and Maintenance Miscellaneous Service and Maintenance Cleaning the Display Materials Use a soft lint free cloth Use a solution with 99 5 IPA isopropyl alcohol or a high quality window cleaning solution Technique Do not rub back and forth with a polishing motion Use a single swipe from the soiled location to the nearest edge of the display Battery Maintenance See the Working with the Lithium lon Battery section of the FieldFox User s Guide for information on the removable battery In particular see Built In Battery Gauge and Reconditioning the Battery Service Guide N9912 90003 8 7 General Purpose Maintenance and Service Procedures RF Analyzer Miscellaneous Service and Maintenance N9912A 8 8 Service Guide N9912 90003 Index A1 keypad illustrated 6 5 part number 6 5 removal and replacement 7 6 A2 LCD illustrated 6 5 operation 5 6 part number 6 5 removal and replacement 7 18 A3 front panel interface board illustrated 6 5 operation 5 5 part number 6 5 removal and replacement 7 18 A4 RF b
76. ll the front panel group assemblies removed in step 3 Refer to Removing and Replacing the Measurement Group Assemblies on page 7 25 to reinstall the measurement group assemblies removed in step 2 10 Reinstall the rear case onto the front case Refer to Combining the Front and Rear Cases on page 7 15 7 14 Service Guide N9912 90003 RF Analyzer Repair and Replacement Procedures N9912A Removing and Replacing the Case Group Parts Combining the Front and Rear Cases 1 Install a new gasket on the blank side panel being careful not to stretch it or to damage it in any way Also make sure there is no slack in the gasket A new gasket is provided in the Repair and Re assembly Kit the blank side panel uses the larger of the two gaskets provided If an old gasket must be removed carefully remove it with tweezers being careful not to damage the groove 2 Ifa new gasket has not been installed on the 1 0 side panel install it at this time It will be necessary to remove the 1 0 side panel from the A5 system board Refer to Replacing the 1 0 Side Panel Doors and Gasket on page 7 12 for instructions 3 Position the front and rear cases side by side as shown 4 Plug the battery cable W10 into the 5 system board as indicated Figure 7 11 Combining the Front and Rear Cases 1 Side Panel Blank Side Panel Plug battery Battery Cable W10 cable in here n9912 90003 711 Service Guide N9
77. memory is erased the boot process returns the UserData directories and files to the state as shipped from the factory The System Information screen indicates the time and date of the most recent erase See Chapter 8 for instructions on executing the Erase User data utility Error Log See Chapter 8 for instructions on viewing the error log 1 Windows and Windows CE are U S registered trademarks of Microsoft Corporation Service Guide N9912 90003 5 27 Theory of Operation RF Analyzer Firmware Related Information N9912A The error log is cleared each time the analyzer is powered off Generally an entry in the error log is created whenever an error message is displayed EXAMPLE Attempting to set the frequency to a value of a decimal point will generate an entry in the error log Firmware Upgrades Firmware upgrades are available on the Internet Refer to instructions in the Update FieldFox Firmware section of the FieldFox User s Guide for details See Chapter 8 for instructions on viewing the current firmware revision The following information will be included in the display Firmware Release FieldFox application firmware revision FPGA Rev code revision for FPGA Boot Rev revision of boot code for System Microcontroller SBM Main Rev revision of main code for System Microcontoller A firmware upgrade includes three sections theFieldFox application firmware and the Windows CE operation system
78. most recent state of the current mode when you change to another mode For most screens under System 7 key the current measurement mode continues to operate while the screen is displayed For instance while the battery information screen is displayed the measurement mode remains active There are two exceptions to this the Options Licensing screen Error Log screen When either of these screens is displayed the firmware is in a special monitor mode and measurements are 5 20 Service Guide N9912 90003 RF Analyzer Theory of Operation N9912A Operation in Modes suspended CAT and NA Modes CAT and NA modes have some similar capabilities but are still separate operating modes Measurement similarities Return Loss 11 magnitude Insertion Loss S21 magnitude Unlike 11 and S21 the values displayed below zero for Return Loss and Insertion Loss are not negative Measurements are done at an effective IFBW IF bandwidth of 30 kHz except when max for Interference Rejection measurements when it is at a 300 Hz effective IFBW There is no user control of the output power level of the source synthesizer on the A4 RF board The only user control of output power level is the high low setting on the RF Out Atten 30 dB in or out Details About One Port Measurements Refer to the block diagram below showing the signal paths highlighted in color Figure 5 4 Signal Paths for One Port CAT NA Measurements A4 RF
79. n 2 5 Option UK6 commercial calibration 2 4 options analyzer 2 3 re installing options 8 5 view currently installed options 8 5 ordering information replaceable parts 6 3 P part numbers documentation 6 14 repair and reassembly kit 6 14 replaceable parts in front panel assembly 6 5 miscellaneous analyzer 6 14 supplies ESD 6 14 tools service 6 14 parts in front panel illustrated 6 5 in front panel assembly part numbers 6 5 miscellaneous part numbers 6 14 replaceable listing of 6 5 ordering information 6 3 performance tests N7841A 3 7 post repair procedures 7 37 power control 5 17 management 5 17 operation 5 17 smart management operation 5 17 states 5 17 supplies 5 17 pre repair procedures caution about 7 3 warnings about 7 3 protection against ESD 1 5 3 3 4 3 7 3 0 QuickCal 5 25 removing assemblies See specific assembly parts See specific part repair post repair procedures 7 37 procedures caution about 7 3 warnings about 7 3 repair and reassembly kit contents 6 14 part number 6 14 replaceable parts in front panel illustrated 6 5 in front panel assembly part numbers 6 5 listing of 6 5 miscellaneous analyzer part numbers 6 14 ordering information 6 3 replacement A1 keypad 7 6 A2 LCD 7 18 A3 front panel interface board 7 18 Ab system board 7 25 A6 SOM board 7 25 assembly cautions about 7 4 list of procedures 7 4 sequence 6 4 7 4 warnings
80. n be in or out Nominal gain of the pre amp is 22 dB The Attn and PA indicators in the display header give current status The Scale Amptd hard key provides access to control for them The displayed measured value for a given signal is automatically compensated for in the current Attn and PA settings For instance if an incoming signal is measured at 70 dBm with the RF IN Atten set to 5 dB and PA out changing to PA in will give a measured value of approximately 70 because the 22 dB for the PA is only nominal The difference seen in the trace will be that the noise floor of the trace will be lowered by approximately 22 dB If the RF In Atten is changed from 5 dB to 15 dB the measured value will not change significantly still approximately 70 dBm but the noise floor will raise by 10 dB SA has two basic modes step and FFT Step mode reads a narrow slice of the spectrum and the LO steps for each slice In this mode a trace on the display is composed from multiple slices Generally spans greater than 100 kHz operate in step mode FFT mode reads a wide slice of the spectrum and the LO is fixed In this mode a trace on the display is based on a single LO setting The LO minimum step size is 2 MHz this restriction limits spurs The hardware operation of the A D s is essentially the same for both step and FFT modes The difference is the digital signal processing The SA adjustments generally correct the gain with 11 fre
81. nalyzer This option allow the N9912A to make spectrum analyzer measurements from 100 kHz to 4 GHz This option can be installed only on a 4 GHz unit Option 231 6 GHz Spectrum Analyzer This option allow the N9912A to make spectrum analyzer measurements from 100 kHz to 6 GHz This option can be installed only on a 6 GHz unit Option 235 Preamplifier for Spectrum Analyzer This option adds a preamplifier to the input port for spectrum analyzer measurements Service Guide N9912 90003 2 3 General Product Information RF Analyzer Keysight Support Services and Assistance N9912A Option 302 External USB Power Sensor Support This option allows the use of an external USB controllable power sensor Option 303 Network Analyzer Capability This option allows the N9912A to make one port network analyzer measurements For two port network analyzer measurements add Option 110 Keysight Support Services and Assistance Information on the following topics is included in this section Service and Support Options Calibration Options Contacting Keysight Shipping Your Analyzer to Keysight for Service or Repair Service and Support Options The analyzer s standard warranty is a one year return to Keysight Technologies service warranty NOTE There are other repair and calibration options available from Keysight Technologies Contact Keysight for additional information on available service agreements for this product Refer to
82. nnectors to protect the connectors 10 Perform the steps under Post replacement Procedure on page 7 37 Figure 7 19 Replacing the RF Top Panel Assembly Connector Plug BNC Connector RF Top Tethered cap Nut and Washer Panel 1 Cable W3 6 places n9912_90003_718 Service Guide N9912 90003 7 27 Repair and Replacement Procedures RF Analyzer Removing and Replacing the Measurement Group Assemblies N9912A Replacing the Type N RF Connectors and RF Cables 1 2 10 11 12 13 14 Separate the front and rear cases See Separating the Front and Rear Cases on page 7 8 Remove all measurement group assemblies as one unit Refer to Removing All Measurement Group Assemblies as One Unit on page 7 25 Remove the RF top assembly Refer to Replacing the RF Top Panel Assembly on page 7 27 Disconnect the cable connector nut on cable W1 or W2 depending on which connector or cable is being replaced Do not attempt to remove the cable just release the connector nut Remove the two screws item 2 from the type N RF connector to be replaced Lift the type N RF connector upwards and out of the RF bottom shield The RF input cable can now be replaced by disconnecting the other end of the cable and removing it When installing the new cable do not tighten either of the cable connector nuts until both of them have been installed finger tight Remove the RFI O ring Remove the old insulator and
83. o 10 in Ib 9 16 inch open end torque wrench set to 21 in Ib Repair and Re assembly Kit Refer to Miscellaneous Parts on page 6 14 WARNING Before beginning any repair remove the battery and disconnect external power NOTE If the FieldFox serial number is below xx4910xxxx and either the Ab System board or the RF assembly is being replaced see Keysight Service Note N9912A 03 It may be necessary to replace both assemblies at the same time Removing All Measurement Group Assemblies as One Unit 1 2 Separate the front and rear cases Refer to Separating the Front and Rear Cases on page 7 8 Disconnect the Ab system board to A3 FPIB cable W14 at the A3 FPIB connector If replacing this cable disconnect both ends Lift the measurement group assemblies out of the front case and position them to the side of the front case as shown Disconnect the A2 LCD to Ab system board cable W11 at the Ab system board connector It is necessary to first remove the adhesive tape that is over the connector To replace this cable refer to Replacing the A2 LCD the LCD Shield and LCD Cables on page 7 20 The measurement group assemblies are now completely separated from the analyzer To remove the 1 0 panel refer to Replacing the 1 0 Side Panel Doors and Gasket on page 7 12 Service Guide N9912 90003 7 25 Repair and Replacement Procedures RF Analyzer Removing and Replacing the Measurement Group Assemblies N9912A Figure 7
84. oard operation 5 7 Ab system board operation 5 12 removal and replacement 7 25 A6 SOM board operation 5 16 removal and replacement 7 25 adjustments 3 8 analyzer miscellaneous replaceable parts part numbers 6 14 options 2 3 system block diagram 5 4 warmup time 3 3 ANSI Z540 standards compliant calibration Option A6J 2 5 assemblies replacement cautions about 7 4 list of procedures 7 4 sequence 6 4 7 4 warnings about 7 4 battery cable removal and replacement 7 6 charging management 5 18 information screen 5 18 operation 5 16 5 18 temperature 5 24 battery disposal 1 7 battery main removal and replacement 7 5 battery RTC removal and replacement 7 18 before applying power 1 4 C calibration ANSI 7540 standards compliant Option A6J 2 5 commercial Option UK6 2 4 in CAT and NA modes 5 25 ISO 17025 standards compliant Option 1A7 2 4 one port 5 25 options available 2 4 QuickCal 5 25 two port 5 25 types 5 25 care of connectors 3 4 case group removal and replacement procedure 7 6 cases removal and replacement 7 6 caution 1 3 CE mark 1 6 check operational 3 6 checklist before return to customer 3 6 checks and procedures manual 7 38 commercial calibration Option UK6 2 4 compare instrument serial numbers 7 38 connector care principles of 3 4 quick reference 3 4 connectors care of 3 4 contacting Keysight 2 5 CPU board operation 5 16 removal and rep
85. on Refer to the following manual checks and procedures for details Service Guide N9912 90003 Repair and Replacement Procedures RF Analyzer Post Repair Procedures N9912A Manual Checks and Procedures Manual Check of Keyboard Check that each key works properly Check that the keyboard backlight LEDs come on when a key is pressed Manual Check of LCD Press Service 7 gt Display then use Display Colors and Brightness keys to exercise the display Check for even brightness in the LCD backlight Manual Check of RPG Operation Activate a marker and use the RPG to move the marker Load Instrument Serial Number into the A5 System Board Instructions for this process may be accessed via the Load instrument serial number into System Board link at keysight com find fieldfox2 Install Firmware from SD Card A specially configured SD card must be used when the flash memory on the A6 SOM board is new or when the A6 SOM board memory has become corrupted Instructions for creating and using the SD card are available at the SD card for installing firmware link at keysight com find fieldfox2 Compare Serial Numbers Compare the serial number stored in the instrument memory with the serial number tag on the back of the instrument To access the stored serial number press System 7 gt Service Diagnostics gt System Information Check Sound Attempt to set a frequency to a value of decimal point a double beep
86. on page 6 14 Service Guide N9 912 90003 Replaceable Parts RF Analyzer Replaceable Parts Listings N9912A Reference Designator Part Number Oty Description 24 W1312 40056 1 Blank side panel 25 1480 0793 4 Dowel pins 26 W1312 60048 1 Door top USB 27 W1312 60049 1 Door middle SD 28 W1312 60050 1 Door bottom LAN Hinge spacer see Figure 6 5 One spacer located between 14 and 6 29 12 00003 r and another spacer located between 16 and 6 Figure 6 4 Case Group Exploded View 4 places 4 places 4 places 4 places 2 23 24 25 6 7 15 8 14 13 16 17 4 21 2 22 9 20 12 11 10 19 18 2 places 2 places 28 27 26 6 places The front case 1 comes with the A1 keypad installed n9912_90003_604 Service Guide N9912 90003 RF Analyzer Replaceable Parts N9912A Replaceable Parts Listings Figure 6 5 Hinge Spacer Locations 2 places 29 n9912_90003_605 Service Guide N9912 90003 6 13 Replaceable Parts RF Analyzer Replaceable Parts Listings N9912A Miscellaneous Parts Table 6 1 Part Numbers for Miscellaneous Parts and Accessories Model or Part Description escriptio Number Repair and Re assembly Kit IMPORTANT This kit is required each time the N9912A case is opened for any reason The kit includes the following items some or all of
87. on the A6 SOM board the firmware in the System Monitor Microcontroller on the 5 system board the FPGA code on the 5 system board The System Monitor firmware update and the FPGA code update are executed only if not up to date It is important to maintain power to the analyzer during the update process After unplugging the USB flash memory stick during the firmware upgrade process wait for the analyzer to activate the CAT mode before operating the analyzer 5 28 Service Guide N9912 90003 RF Analyzer Theory of Operation N9912A LAN Interface LAN Interface See the System Configuration section of the FieldFox User s Guide for details on reviewing and configuring LAN settings Currently the LAN interface supports only communication for the Data Link software and sending SCPI commands for service purposes The LAN interface supports Auto MDIX When a LAN cable is connected to the FieldFox if the other end of the cable supports Auto MDIX there is no need for a cross over cable There are two LEDs on the LAN connector When there is successful communication over a LAN cable both LEDs are active If both LEDs are not active consider using a cross over cable Service Guide N9912 90003 5 29 Theory of Operation RF Analyzer LAN Interface N9912A 5 30 Service Guide N9912 90003 6 Replaceable Parts Service Guide N9912 90003 Replaceable Parts RF Analyzer Information in This Chapter N9912A Information in This C
88. one sweep for the NA R signal and a second sweep for the SA signal Because of the shared LO and A D no phase relationship is available only magnitude When measuring the SA signal the source and SA receiver step through each frequency point in the sweep The SA receiver is effectively in step mode and tuned to the source frequency The SA Pre amp is always switched out 5 22 Service Guide N9912 90003 RF Analyzer Theory of Operation N9912A Operation in Modes The RF In Atten is not under user control For a given frequency the ADC Overload Adjustment determines the setting for this attenuator to prevent over range warnings There is no default calibration for two port measurements Uncalibrated not normalized measurement of a short thru cable typically shows a trace with some sawtooth characteristics SA adjustment results are ignored when in CAT NA mode T he raw unadjusted readings are used There is one exception the results of the IF Offset Adjustment are used during CAT NA modes SA Mode The signal path for SA mode is the same as the input path for two port CAT NA modes The RF In Atten can be set to 32 different levels nominal 0 through 31 dB in 1 dB steps The Attenuator Slope Adjustment determines the correction factors for each step in each frequency band The RF In Atten can be controlled manually or automatically When in auto mode the Reference Level setting determines the attenuator setting The Pre amp ca
89. portant information about shipping your analyzer to Keysight for service or repair 2 2 Service Guide N9912 90003 RF Analyzer General Product Information N9912A Maintenance Maintenance WARNING To prevent electrical shock disconnect the analyzer from the mains source before cleaning Use a dry cloth or one slightly dampened with water to clean the external case parts Do not attempt to clean internally Physical Maintenance Clean the analyzer case using a dry or slightly damp cloth only Electrical Maintenance Refer to Contacting Keysight on page 2 5 and to Chapter 3 Tests and Adjustments Analyzer Options Below is a list of options available for the FieldFox N9912A at the time of initial product release Additional options will be added as product features are enhanced Go to www keysight com find fieldfox2 for information on currently available upgrade options Option 110 Transmission Measurement This option allows use of the second port in either the NA network analyzer or CAT cable and antenna test modes for transmission measurements Option 111 QuickCal This option provides a calibration that is performed automatically using calibration standards that are built in to the N9912A Calibration standards are automatically switched in as needed QuickCal is ideal for making quick and cable loss measurements without taking the time to perform a full O S L Cal Option 230 4 GHz Spectrum A
90. power to the analyzer such as removing the main battery when the analyzer is not connected to external power should not cause any problems Simply re apply power No firmware problems are expected Of course this does not apply during a firmware upgrade Smart Power Management The analyzer uses extensive load switching to minimize power dissipation This is termed Smart Power Management SPM There are two motivations for power management to extend battery run time e to prevent overheating Sections of the circuitry are selectively powered down via load switching depending on the operating mode of the analyzer Five different sections of the circuitry on the A4 RF board may be controlled via load switching These sections are as follows e Source switched off during SA mode switched off between sweeps during or NA modes LO switched off when data is not being taken by receivers switched off when in one port CAT or NA modes on all the time in two port mode Reflectometer switched to low power through state when RF OUT port receivers are inactive High Band Pre amp switched off when not required On the system board each of the ADC s may be individually switched to a low power mode when not active Load switching is generally transparent to the user One obvious exception is the that the source turns off during retrace in the CAT and NA modes Battery Related Information
91. quency bands See SA Frequency Bands on page 5 10 for a listing of the 11 bands See the TME help file for details on SA adjustments Power Meter Mode All measurement circuitry is switched to the low power state during PM power meter mode This is the mode with the lowest power dissipation The analyzer has no power output capability in this mode The analyzer essentially functions as a display for a USB power sensor Service Guide N9912 90003 5 23 Theory of Operation RF Analyzer Temperature Related Information N9912A Temperature Related Information Five temperature sensors are in the analyzer two on the A4 RF board two on the A5 system board and one in the battery pack RF1 NA Temp Sensor on the A4 RF board near the NA circuitry RF2 8A Temp Sensor on the A4 RF board near the SA circuitry B1 on the Ab system board near the headphone jack SB2 on the 5 system board near the battery compartment Battery pack inside the battery pack The battery pack has its own internal temperature sensor The battery pack will shut itself down in the case of extreme temperatures See Chapter 8 for instructions on viewing temperature readings See the FieldFox User s Guide FieldFox High Temperature Protection section for information about operation at high temperature The temperature readings for sensor RF2 are stored as part of the adjustment data for the Frequency Response Preamp On Off adjustments Dur
92. ration ANSI 7540 Option A6J 2 5 ISO 17025 Option 1A7 2 4 strap handle removal and replacement 7 6 supplies ESD part numbers 6 14 support contacting Keysight 2 5 options 2 4 organization 2 4 system board operation 5 12 T temperature battery pack 5 24 related information 5 24 screen 5 24 test equipment service 3 5 tests 3 8 performance N7841A 3 7 tools service part numbers 6 14 troubleshooting front panel group 4 7 measurement group 4 8 power up 4 6 where to begin 4 4 U upgrades firmware 5 27 user accessible files 5 27 user data erase utility 8 3 view current firmware revision 8 3 currently installed options 8 3 8 5 temperature readings 8 3 the error log 8 3 warm up analyzer 3 3 warning 1 3 warranty service standard 2 4 three year return to Keysight 2 4 Service Guide N9912 90003 Index 3 Index Index 4 Service Guide N9912 90003 This information is subject to change without notice Keysight Technologies 2008 2014 August 2014 www keysight com KEYSIGHT TECHNOLOGIES N9912 90003
93. re sensor is nearest the NA circuitry RF2 temperature sensor SA Temp Sensor is located through the A4 RF board from FL1202 on the 5 system board side of the A4 RF board This temperature sensor is nearest the SA circuitry Service Guide N9912 90003 5 11 Theory of Operation RF Analyzer Measurement Group N9912A Ab System Board The A5 system board controls all of the functions of the analyzer and digitizes the RF IF signal from the A4 RF board The A6 SOM System on Module board is mounted directly on the Ab system board All external connections for the analyzer come through the Ab system board except for the RF IN and RF OUT ports The A5 system board also controls the power switching and power management The instrument model number and serial number are stored on the A5 system board System Monitor SM Microcontroller This is the heart of the analyzer It is active whenever there is DC power available The microcontroller has ultra low power dissipation It is sometimes referred to as the MSP 430 The following is a list of some of the functions performed by the SM e It monitors the On Off button on the front panel and responds appropriately It controls the on off functions of the various power supplies in the analyzer It drives the On Off button LED e treads battery pack information via the Smart Batt Bus tcommunicates with the battery charger IC via the Smart Batt Bus Itinterfaces to the Battery
94. rement Group Assemblies N9912A Figure 7 23 Replacing the RF Assembly Including the A4 RF Board BNC Connector Nut and Washer Cable W3 A4 RF Board View of the RF Assembly After Removing the A5 System Board n9912_90003_722 7 34 Service Guide N9912 90003 RF Analyzer Repair and Replacement Procedures N9912A Removing and Replacing the Measurement Group Assemblies Reinstalling All Measurement Group Assemblies as One Unit 1 Reinstall the 1 0 side panel if needed Refer to Replacing the 1 0 Side Panel Doors and Gasket on page 7 12 Position the measurement group assemblies to the side of the front case as shown in Figure 7 18 on page 7 26 Refer to Removing All Measurement Group Assemblies as One Unit on page 7 25 Reconnect the LCD to system board cable at the system board connector and place a strip of adhesive tape over the connector to secure it This strip of adhesive tape is provided in the Repair and Re assembly Kit If necessary refer to Replacing the A2 LCD the LCD Shield and LCD Cables on page 7 20 Position the measurement group assemblies on top of the front case and align the 1 0 side panel in the groove in the front case being careful not to damage the gasket Position tuck the LCD to system board cable in between the LCD shield and the 5 system board so that it will not interfere with the cases when they are combined Reconnect the system board to front panel interface board cable at
95. rent Firmware Revision Etc Press System 7 Press Service Diagnostics Press System Information The System Information screen includes the following information L Model Number instrument model number Serial Number instrument serial number Firmware Release version of installed firmware L Network Identity computer name and current IP address RF Serial Number serial number of RF PCA L1 SB Serial Number serial number of System Board PCA FP Serial Number serial number of Front Panel PCA 4 UserData Erased the most recent date and time User Data Erase performed To View the Error Log Press System 7 Press Service Diagnostics Press Error Log See the Firmware Related Information section of Chapter 5 for details on the error log To View Temperature Readings Press System 7 Press Service Diagnostics Press Internal Temperatures Service Guide N9912 90003 8 3 General Purpose Maintenance and Service Procedures RF Analyzer Service Related User Operations N9912A See the Temperature Related Information section of Chapter 5 for details Erase User Data Utility Press System 7 Press Service Diagnostics Press Advanced Press Erase User Data Press Confirm Erase The UserData memory portion is erased then the instrument restarts See the Firmware Related Information section of Chapter 5 for details on the Erase User Data utility 8 4 Service Guide
96. res Replaced Assembly Adjustments etc TME Tests or Other Procedures Main battery None needed None needed RPG None needed Manual check of RPG operation RF OUT connector or associated cable W1 replaced or disturbed None needed Error Terms test RF IN connector or associated cable W2 replaced or disturbed None needed Station Calibration for tests Absolute Amplitude Accuracy Test Frequency Response Preamp Off test Frequency Response Preamp On test Front case including A1 keypad None needed Manual check of keyboard A2 LCD None needed Manual check of LCD A3 front panel interface board None needed Manual check of keyboard Check for even brightness in LCD backlight Check sound A4 RF board TME based adjustments that apply to the installed option configuration All TME based tests that apply to the installed option configuration Ab system board First load the instrument serial number into the Ab system board TME based adjustments that apply to the installed option configuration All TME based tests that apply to the installed option configuration A6 SOM board Install firmware from SD Re install options TME based adjustments that apply to the installed option configuration Compare serial numbers All tests that apply to the installed option configurati
97. rnet and a license purchased on line or it can be ordered on a CD ROM Go to www keysight com find calibrationsoftware for further information There are Four tests for the general functionality of the analyzer Seven additional tests for the SA spectrum analyzer functions Total test time will vary from 7 to 36 minutes depending upon options installed Details for these tests and recommended troubleshooting information can be found in the N7841A help file General Tests Total test time for these tests is 8 minutes Frequency Accuracy Test Error Terms Test CAT Functional This test includes an adjustment see Adjustments Keysight N7841A Software Package on page 3 8 and should be performed every 12 months High Low Output Power Output Test CAT Functional Crosstalk S21 Test CAT Functional Spectrum Analyzer Specific Tests Total test time for these tests is 29 minutes Absolute Amplitude Accuracy Test FFrequency Response Test Functional Frequency Response with Preamp Off Test Frequency Response with Preamp On Test Displayed Average Noise Level with Preamp On Test Noise Sidebands Test Service Guide N9912 90003 3 7 Tests and Adjustments RF Analyzer Adjustments Keysight N7841A Software Package N9912A Adjustments Keysight N7841A Software Package The adjustments section of the Keysight N7841A software package may be used to fine tune your analyzer The N7841A software package
98. rostatic Discharge ESD Protection 7 3 Assembly Replacement cece ccc ccc hens 7 4 Removal and Replacement 7 4 Removing and Replacing the Main Battery 7 5 Removing and Replacing the Case Group 0 00 c cece eect ses 7 6 Removing and Replacing the Front Panel Group Assemblies 7 18 Removing and Replacing the Measurement Group Assemblies 7 25 Post Repait Procedures Gace eet edo ve aa date A ale dla ada meee RU 7 37 Manual Checks and Procedures 200 c cece cece cece eect ete s 7 38 8 General Purpose Maintenance and Service Procedures Information in This IRI nee eee e ene 8 2 Chapter Eight at a Glance ene me 8 2 Service Related User 5 8 3 To View Currently Installed Options cece cee IHR 8 3 To View the Current Firmware Revision Etc 0 0 0 cece cece cece cece n 8 3 To View the 1 m mr 8 3 To View Temperature lt 8 3 Erase User Data Utility Imm 8 4
99. s RF Analyzer Assembly Replacement Procedure N9912A Assembly Replacement Procedure The following steps describe how to replace an assembly in the analyzer Step 1 Identify the faulty group Begin with Chapter 4 Troubleshooting Follow up with the appropriate troubleshooting chapter that identifies the faulty assembly Step 2 Order a replacement assembly Refer to this chapter for part numbers and ordering information Step 3 Replace the faulty assembly and determine what adjustments and performance tests are necessary Refer to Chapter 7 Repair and Replacement Procedures Step 4 Perform the necessary adjustments Refer to Chapter 3 Tests and Adjustments Step 5 Perform the necessary performance tests Refer to Chapter 3 Tests and Adjustments 6 4 Service Guide N9912 90003 RF Analyzer Replaceable Parts N9912A Replaceable Parts Listings Replaceable Parts Listings Entire Analyzer Figure 6 1 Entire Analyzer Exploded View Case Group Front Panel Group Measurement Group Case Group RPG Knob Battery Front Panel Miscellaneous Parts Group n9912_90003_601 Descriptions and part numbers for the assemblies and parts in each group shown in the above illustration can be found at the following locations Front Panel Group on page 6 6 Measurement Group on page 6 8 Case Group on page 6 11 Miscellaneous parts and accessories not illustrated in any of these groups ar
100. s for removing and replacing the See Table 7 1 major assemblies in your analyzer on page 7 4 The procedures occur in assembly reference designator procedures numerical order Post Repair Procedures A table of the proper tests verifications and Page 7 37 adjustments to perform on your analyzer after repair 7 2 Service Guide N9912 90003 RF Analyzer Repair and Replacement Procedures N9912A Personal Safety Warnings Personal Safety Warnings WARNING These servicing instructions are for use by qualified personnel only To avoid electrical shock do not perform any servicing unless you are qualified to do so WARNING Danger of explosion if battery is incorrectly replaced Replace only with the same or equivalent type recommended Discard used batteries according to manufacturer s instructions Safety Earth Ground WARNING This is a Safety Class product provided with a protective earthing ground incorporated in the power cord The mains plug shall only be inserted in a socket outlet provided with a protective earth contact Any interruption of the protective conductor inside or outside of the instrument will make the instrument dangerous Intentional interruption is prohibited CAUTION Always use the three prong AC power cord supplied with this product Failure to ensure adequate grounding by not using this cord may cause product damage Electrostatic Discharge ESD Protection CAUTION Many of the
101. strap handle from the two dowel pins 6 Remove the blank side panel from the groove in the front case Figure 7 5 Separating the Front and Rear Cases 2 E Dowel Pin 2 places Strap Handle Battery Blank Cable Side Panel W10 n9912_90003_705 Service Guide N9912 90003 7 9 Repair and Replacement Procedures RF Analyzer Removing and Replacing the Case Group Parts N9912A 7 Position the cases side by side as shown in Figure 7 6 8 Unplug the battery cable W10 from the Ab system board at the location indicated 9 The front and rear cases are now completely separated 10 Remove the blank side panel by lifting it from the groove in the front case NOTE If the FieldFox serial number is below xx4910xxxx temporarily remove the LCD shield and verify that two strips of adhesive tape are in place as shown in Figure 7 15 on page 7 21 To remove the LCD shield follow Step 2a on page 7 20 If the two strips of adhesive tape are not in place install them by following Step 2h on page 7 20 Figure 7 6 Separating the Front and Rear Cases 3 Blank Side Panel A Ba AS A KK A zemne H D sy al Unplug battery Battery Cable cable here w10 n9912_90003_706 7 10 Service Guide N9912 90003 RF Analyzer Repair and Replacement Procedures N9912A Removing and Replacing the Case Group Parts Replacing the Battery Cable 1 Separate the front and rear cases
102. t Failure to ensure adequate grounding by not using this cord may cause product damage Service Guide N9912 90003 1 3 Safety and Regulatory Information RF Analyzer General Safety Considerations N9912A Before Applying Power WARNING CAUTION CAUTION Servicing WARNING WARNING WARNING WARNING WARNING 1 4 If this product is not used as specified the protection provided by the equipment could be impaired This product must be used in a normal condition in which all means for protection are intact only This product is designed for use in Installation Category Il and Pollution Degree 2 per IEC 61010 1 2001 and 664 respectively The measuring terminals on this instrument are designed to be used with external signals described in Measurement Category but NOT with external signals described in Categories Il and IV The input of this instrument cannot be connected to the mains These servicing instructions are for use by qualified personnel only To avoid electrical shock do not perform any servicing unless you are qualified to do so Danger of explosion if battery is incorrectly replaced Replace only with the same or equivalent type recommended Discard used batteries according to local ordinances and or manufacturer s instructions No operator serviceable parts inside Refer servicing to qualified personnel To prevent electrical shock do not remove covers For continued protection against fire hazard
103. tacks Backlight brightness is a function of the backlight power that ranges from 22 to 27 volts Refer to Backlight Power on page 5 5 for more information The backlight LED s are arranged along the top and bottom edges of the display There are three stacks on each edge 5 6 Service Guide N9912 90003 RF Analyzer Theory of Operation N9912A Measurement Group Measurement Group The measurement group produces a stable output signal by phase locking a synthesized voltage controlled oscillator VCO The measurement group consists of the A4 RF Board Ab System Board A6 SOM Board Main Battery A simplified RF block diagram is provided in Figure 5 2 A simplified system block diagram is provided in Figure 5 3 A4 RF Board The basic function of the A4 RF board is to provide a signal source and receivers for the analyzer functions There are three sections to the A4 RF board the Common RF section the CAT NA RF section and the section Common RF Section This section is common to both NA and SA functions In this common section an LO synthesizer produces a single LO signal from the 30 MHz time base located on the 5 system board The LO output is switched between the NA mixers and the SA first converter depending on the function being used At any instant in time either the receivers or the SA receiver may be active but not both at the same time The LO frequency bands are listed below
104. the front panel interface board connector as shown Service Guide N9912 90003 7 35 Repair and Replacement Procedures Removing and Replacing the Measurement Group Assemblies Figure 7 24 Ol Side Panel 7 36 Clo LIE oW i ree 7 RF Analyzer N9912A Replacing All Measurement Group Assemblies as One Unit 1 m ULT Deu Em B E 7508 amp Side Panel Reconnect cable W11 here and secure with adhesive tape Tuck cable W11 in between LCD shield and A5 system board Reconnect cable W14 to front panel interface board here D U H z eie QUE zrol b CTs 8 ec A n9912_90003_723 Service Guide N9912 90003 RF Analyzer N9912A Post replacement Procedure Repair and Replacement Procedures Post Repair Procedures 1 Reinstall the measurement group assemblies into the front case Refer to Reinstalling All Measurement Group Assemblies as One Unit on page 7 35 2 Combine the front and rear cases Refer to Combining the Front and Rear Cases on page 7 15 Post Repair Procedures After the replacement of an assembly you must perform the service procedures in the order listed in Table 7 2 Procedures referenced in this table are located in Chapter 3 Tests and Adjustments unless specified otherwise Table 7 2 Related Service Procedu
105. the three doors in the new I O side panel a Place each door in its respective opening with the hinges aligned with the hinge slots in the side panel b Press the hinges into their slots until they snap into place Figure 7 9 Replacing the 1 0 Side Panel Doors and Gasket Hinge socket Press here on hinge until the hinge ball snaps into the hinge socket Hinge ball Install new gasket in groove here n9912_90003_709 6 Before installing the new 1 0 side panel or when reinstalling the existing 1 0 side panel install a new gasket in the groove around the perimeter of the panel If an old gasket must be removed use tweezers being careful not to damage the groove Start in the groove near the flat end of the side panel Be careful not to stretch or damage the gasket in any way Also make sure there is no slack in the gasket A new gasket is provided in the Repair and Re assembly Kit see page 6 14 It is the smaller of the two gaskets provided in the kit 7 To install the new 1 0 side panel place it in position on the system board and reinstall the two attachment screws See Figure 7 8 8 Reinstall the measurement group assemblies RF top panel assembly A4 RF board Ab system board and SOM board as one unit with the new 1 0 panel attached 9 Reinstall the rear case onto the front case See Combining the Front and Rear Cases Service Guide N9912 90003 7 13 Repair and Replacement Procedures
106. these screws new ones are provided in the Repair and Re assembly Kit b Unplug the SOM board from the 5 system board c Plug the new A6 SOM board into the A5 system board d Install four new screws item 3 from the Repair and Re assembly Kit and tighten them in the torque sequence indicated by the circled numbers in the illustration To replace the flexible RF cables aidin reinstallation note the connector to which each cable end is connected before disconnecting the cable Refer to Figure 5 1 on page 5 4 for an electrical diagram of each cable connection b Cables W4 and W6 are provided as an assembly When replacing this coax cable assembly 1 Make sure the cable connectors are positioned as shown and that the cable assembly is routed as shown Cable W6 is the one with a red mark on each connector 2 Ensure that there is no slack in the cables at the top connections as indicated 3 Make sure that the cable assembly does not touch the TCXO chip on the Ab system board 4 Clip cable W6 into each of the cable clamps on the A5 system board Cable W6 is the one with a red mark on each connector To replace cable W5 or W7 1 Disconnect the appropriate cable and install the new cable being sure to position it as shown 5 To remove the 1 0 panel refer to Replacing the 1 0 Side Panel Doors and Gasket on page 7 12 6 Perform the steps under Post replacement Procedure on page 7 37
107. this procedure b Disconnect the RPG cable W12 from the A3 front panel interface board c Using a 7 16 inch hex nut wrench remove the hex nut from the RPG shaft d Pull the RPG out the back side of the front case and retrieve the lock washer from the front side e To install a new RPG reverse the above steps A new cable nut and washer are included with the new RPG When reinstalling the RPG cable W12 bend the cable toward the right side on top of the display to front panel interface board cable 5 Reinstall the hole plugs in the front case Apply one drop of isopropyl alcohol on each hole plug to lubricate it making it easier to install Use alcohol only in a well ventilated area View the hole plugs from the front to ensure that they are fully seated These hole plugs must be installed to maintain 7 18 Service Guide N9912 90003 RF Analyzer Repair and Replacement Procedures N9912A Removing and Replacing the Front Panel Group Assemblies water tight integrity 6 Reinstall the RPG knob Refer to step 3 b of this procedure 7 Perform the steps under Post replacement Procedure on page 7 24 Figure 7 14 Replacing the RPG and RPG Knob Disconnect RPG cable here RPG Hex Lock Knob Nut Washer Push RPG knob off of n9912 90003 714 Service Guide N9912 90003 Repair and Replacement Procedures RF Analyzer Removing and Replacing the Front Panel Group Assemblies N9912A Replacing the A2 LCD the LCD Shield and LC
108. this screen Most of the items displayed on the screen come directly from the battery via the Smart Batt Bus Only the first three items are influenced by the analyzer Battery Charging Management The battery pack determines when the battery needs charging and requests a charge over the Smart Batt Bus The Battery Charger and Manager circuit on the system board responds by charging the battery if there is sufficient voltage on the Ext DC line A minimum of approximately 15 volts is required to charge the battery The System Monitor on the A5 system board monitors the battery s temperature and if too high or too low disables charging of the battery How to tell if the battery is charging e Ifthe analyzer is On the lightening bolt is displayed in the battery icon Ifthe analyzer is Off the LED below the On Off Button slowly flashes orange with increasing intensity e Ifthe analyzer is in Standby turn the analyzer on and observe the battery icon The battery charges much faster up to 7096 of its full charge than it does above 7096 of full charge Battery Life When a battery is new an instrument should operate for about four hours on a fully charged battery The actual time will depend on operating mode and temperature As a battery goes through charge discharge cycles its capacity will decrease A typical battery will have more than 7096 of its initial capacity after 200 full discharge cycles when operating at 20 to 30 xC amb
109. time the N9912A case is opened for any reason you must order a Repair and Re assembly Kit See Miscellaneous Parts on page 6 14 Service Guide N9912 90003 RF Analyzer Replaceable Parts N9912A Replaceable Parts Listings Reference Designator Part Number Qty Description 32 0515 0430 6 Screw machine w crest cup washer pan head M3 0 x 6 mm 33 0515 1940 4 Screw machine w patch lock pan head M2 5 x 6 mm 34 0515 2349 6 Screw machine 90 deg flat head M3 0 x 14 mm Service Guide N9912 90003 6 9 Replaceable Parts RF Analyzer Replaceable Parts Listings N9912A Figure 6 3 Measurement Group Exploded View 22 _ay 29 W3 27 248 2 places 22 d 6 places 34 _ Y 4 places 17 CT 2 places 13 2 places 15 W1 11 i 2 places 4 W2 10 on L SAG 31 m oa WD We Items 2 3 5 6 4 places ni F Ss 7 8 9 12 14 16 4 v eC of the RF assemby 26 ai 20 19 System Board 33 2 places 32 6 places 4 places W4 W6 Cable Assy n9912 90003 603 6 10 Service Guide N9912 90003 RF Analyzer N9912A Case Group Replaceable Parts Replaceable Parts Listings Reference Designator Part Number Oty Description Replacement Assemblies Front Enclosure Assembly N9912 60020 Front Enclosure Assembly Includes Front case with A1 keypad installed 1
110. tion Definitions of instrument markings Regulatory Information Instructions for disposing of the analyzer s lithium Page 1 6 battery 1 2 Service Guide N9912 90003 RF Analyzer Safety and Regulatory Information N9912A Safety Symbols Safety Symbols The following safety symbols are used throughout this manual Familiarize yourself with each of the symbols and its meaning before operating this instrument CAUTION Caution denotes a hazard It calls attention to a procedure that if not correctly performed or adhered to could result in damage to or destruction of the instrument Do not proceed beyond a caution note until the indicated conditions are fully understood and met WARNING Warning denotes a hazard It calls attention to a procedure which if not correctly performed or adhered to could result in injury or loss of life Do not proceed beyond a warning note until the indicated conditions are fully understood and met General Safety Considerations Safety Earth Ground WARNING This is a Safety Class product provided with a protective earthing ground incorporated in the power cord The mains plug shall only be inserted in a socket outlet provided with a protective earth contact Any interruption of the protective conductor inside or outside of the instrument will make the instrument dangerous Intentional interruption is prohibited CAUTION Always use the three prong AC power cord supplied with this produc
111. tion about these agreements and for other assistance contact Keysight Refer to Contacting Keysight on page 2 5 Safety and Regulatory Information The safety and regulatory information pertaining to this product is located in Chapter 1 Safety and Regulatory Information Safety Notes The following safety notes are used throughout this manual Familiarize yourself with each of the notes and its meaning before operating this instrument All pertinent safety notes for using this product are located in Chapter 1 Safety and Regulatory Information WARNING Warning denotes a hazard It calls attention to a procedure which if not correctly performed or adhered to could result in injury or loss of life Do not proceed beyond a warning note until the indicated conditions are fully understood and met CAUTION Caution denotes a hazard It calls attention to a procedure that if not correctly performed or adhered to could result in damage to or destruction of the instrument Do not proceed beyond a caution sign until the indicated conditions are fully understood and met Documentation Map On line This Service Guide is available only on the Web via an Internet connection It Service contains information for testing adjusting troubleshooting and repairing your Guide N9912A analyzer Service Guide N9912 90003 iii The User s Guide included with the product helps you to quickly familiarize yourself with the analyzer
112. to Warm Up Before testing or adjusting the N9912A analyzer allow it to warm up as described under DUT Warmup in the Getting Started section of the N7841A help file Service Guide N9912 90003 3 3 Tests and Adjustments RF Analyzer Before You Begin N9912A Review the Principles of Connector Care Proper connector care and connection techniques are critical for accurate and repeatable measurements Refer to Table 3 1 for tips on connector care Prior to making connections to your analyzer carefully review the information about inspecting cleaning and gaging connectors Refer to the calibration kit documentation for detailed connector care information For course numbers about additional connector care instruction contact Keysight Technologies Refer to Contacting Keysight on page 2 5 Table 3 1 Connector Care Quick Reference Guide Handling and Storage Do Keep connectors clean Do Not Touch mating plane surfaces Extend sleeve or connector nut Setconnectors contact end down Use plastic end caps during storage Store connectors or adapters loose Visual Inspection Do Inspect all connectors carefully Do Not Use damaged connector ever Look for metal particles scratches and dents Connector Cleaning Do Try compressed air first Do Not Use any abrasives Use isopropyl alcohol Getliquid into plastic support beads Clean connector threads Gaging Connectors
113. ure 7 5 See Separating the Front and Rear Cases 2 Note the orientation of the strap handle then lift it off of the dowel pins at each end 3 Slip the new strap handle over the dowel pins Service Guide N9912 90003 7 11 Repair and Replacement Procedures RF Analyzer Removing and Replacing the Case Group Parts N9912A 4 Reinstall the rear case onto the front case See Combining the Front and Rear Cases Replacing the 1 0 Side Panel Doors and Gasket 1 Separate the front and rear cases See Separating the Front and Rear Cases on page 7 8 2 Remove the measurement group assemblies RF top panel assembly A4 RF board system board and A6 SOM board as one unit with the 1 0 panel attached but do not disconnect cable W11 from between the A2 LCD and the system board Refer to Removing and Replacing the Measurement Group Assemblies on page 7 25 3 Remove the two screws item 5 that secure the 1 0 side panel to the Ab system board and remove the 1 0 side panel Figure 7 8 Replacing the 1 0 Side Panel lt 5 Side Panel n9912 90003 708 7 12 Service Guide N9912 90003 RF Analyzer Repair and Replacement Procedures N9912A Removing and Replacing the Case Group Parts 4 Remove the three doors from the old 1 0 side panel a Open each door to its stopping point then GENTLY force it beyond its stopping point to separate it from the panel 5 Install
114. when the analyzer has thermally stabilized to room temperature Operation at other temperature conditions may impact measurement accuracy when applying the preset calibration The preset calibration should be re characterized every 12 months to maintain accuracy This is accomplished via the Error Terms test adjustment in the TME Refer to Chapter 3 Under ideal conditions a preset calibration and an OSL open short load calibration should give very similar results for measurements at the RF OUT port Service Guide N9912 90003 5 25 Theory of Operation RF Analyzer User Calibration in CAT and NA Modes N9912A Two Port Calibration Two port calibration applies only when 21 or Insertion Loss measurements are active There is no built in or preset two port calibration in the analyzer A normalize calibration must be performed before making two port measurements QuickCal The QuickCal function mathematically extends the preset calibration to the end of a cable or adapter It is a firmware only function it does not involve analyzer hardware 5 26 Service Guide N9912 90003 RF Analyzer Theory of Operation N9912A Firmware Related Information Firmware Related Information General Description The analyzer is based on the Windows operating system This is a closed system no direct user access to the desktop of general operating system functions is provided The file system for Windows CE is maintained in flash memory on
115. which are necessary to re assemble the internal assemblies and the case depending upon the depth of the repair Repair and Re assembly Kit Includes the following items N9912 60027 Gasket for blank side panel larger size qty 1 N9912 40002 Gasket for 1 0 side panel smaller size qty 1 N9912 40003 Screw machine w flat washer pan head M3 0 x 35 mm qty 6 0515 5153 Screw machine 90 deg flat head M3 0 x 5 mm qty 15 0515 1521 Screw machine w crest cup washer pan head M3 0 x 6 mm qty 6 0515 0430 Screw machine w crest cup washer pan head M3 0 x 10 mm qty 4 0515 0374 Screw machine w patch lock pan head M2 5 x 6 mm qty 4 0515 1940 Screw machine 90 deg flat head M3 0 x 14 mm qty 6 0515 2349 Tape 1 4 inch x 1 inch for LCD ribbon cable qty 3 N9912 20043 Service Tools T 8 TORX driver set to 6 in Ib N A T 10 TORX driver set to 9 in Ib N A 5 16 inch open end torque wrench set to 10 in Ib N A 7 16 inch hex nut wrench or nut driver set to 9 in Ib N A 9 16 inch open end torque wrench set to 21 in Ib N A Documentation Users Guide Can also be printed from the Keysight Web site Refer to Printing Copies of Documentation from the Web on page iv Quick Reference Guide N9912 90002 N9912 90001 Service Guide Not available in printed form Part number is for reference only Must be printed from the Keysight Web site Refer to Printing Copies of Documentation from the N9
116. y voltage Power for the System Monitor circuit 3 3 volt circuit powered from Ext DC or Batt whichever is greater Used on 5 system board only Unreg DC from Ext DC or Batt 21 volts max Ext DC from external Power AC Adapter nominal 15 volts acceptable up to 19 volts Batt from main battery nominal 12 volts All voltages except Ext DC Batt and the System Monitor power can be turned on off within the analyzer Refer to Power Management Circuitry on page 5 10 for more information Power Control and Management Power States The On Off Button is used to switch between On Off and Standby power states Service Guide N9912 90003 5 17 Theory of Operation RF Analyzer Grounding and Power N9912A Off Only the System Monitor and battery control circuits are powered up if power is available from the battery or external power If the battery is charging the LED below the On Off Button slowly flashes orange with increasing intensity otherwise this LED is off Some battery power is required in the Off state A fully charged battery will discharge completely in four to six weeks when left in the analyzer On This is normal operation The On Off Button LED is steadily lit green Standby Only the digital power supplies are on The CPU is in a low power state maintaining RAM content The On Off Button LED flashes yellow briefly every two seconds During normal operation unexpectedly disconnecting
117. ystem board are connected via the common shields at multiple points The ground plane on the A3 front panel interface board is connected to the ground plane on the 5 system board There are no separate grounds in the analyzer There is no star ground point in the analyzer Batt Neg and Ext DC neg are connected to the A5 system board ground plane The A2 LCD assembly has two separate grounding circuits the LCD power and control circuits and the backlight LED s The LCD power and control circuits share a ground that is connected to the ground plane on the 5 system board The ground for the backlight LED s is connected to the ground plane on the A3 front panel interface board Voltages and Power Supplies The following power supplies exist within the analyzer Digital 5 volts generated from Unreg DC on the front panel interface board controlled by the System Monitor on the A5 system board and used on the A3 A4 and Ab boards Digital 3 3 volts generated from Unreg DC on the A3 front panel interface board on off functions controlled by the System Monitor on the A5 system board and used on the A2 LCD assembly and A3 A4 Ab and A6 boards Analog supply voltages seven separate voltages generated from Unreg DC on the 5 system board on off functions controlled by the System Monitor on the Ab system board LCD backlight voltage generated on the front panel interface board from the digital 5 volt suppl
118. yzer Page 5 3 A summary of the operation of the major functional groups of the analyzer Front Panel Group Operation of the assemblies associated with the front Page 5 5 panel group of assemblies Measurement Group Operation of the assemblies associated with the Page 5 7 measurement group of assemblies Operation in Modes Description of the different operating modes and what Page 5 20 hardware is used in each mode Temperature Related Information Information about temperature sensors and how the Page 5 24 analyzer responds to temperature information gathered User Calibration in CAT and NA Descriptions of one port and two port calibrations forthe Page 5 25 Modes CAT and NA modes of operation Firmware Related Information Information about firmware and firmware upgrades Page 5 27 5 2 Service Guide N9912 90003 RF Analyzer Theory of Operation N9912A Analyzer System Operation Analyzer System Operation The N9912A RF analyzer operates as both a network analyzer NA and a spectrum analyzer SA The NA functions support the CAT mode NA function supports one port measurements using the RF OUT port and two port measurements using both the RF IN and RF OUT ports The SA function supports measurements using the RF IN port See Figure 5 1 for a simplified block diagram of the overall RF analyzer system All N9912A RF analyzers have the same hardware Options to increase functionality ar

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