PRC 2000-2M SYSTEMS SERVICE MANUAL ADDENDUM
Contents
1. Timed Timed Switches Recycle 7 Amber When or Continuous Fuse Pump amp Recycling Solenoid Check Status Logic LED Drive Do Solenoid U7A U7B amp Pump U8C Q6 Q7 amp Operate LED Replace U4 Check Q9 8080 Pin 11 Low Square Wave While Driver LED is Amber R83 amp Q20 Check PWM Circuit C7 U3C U7A amp U8D Figure 6 Paste Dispenser Troubleshooting 26 MULTIFUNCTION PCB ASSEMBLY LED Turns Green When Foot Pedal is Pressed 1 Check egre R107 Q21 amp CR25 Check C7 05 C25 C26 amp Does Pump PD Front Panel Operate Pot Check U4 U5 5 Adjust R38 Equals 2 3 So U1 Pin 5 Vec Equals 2 3 Vcc Timing Accurate Timing Accurate Check C7 US C25 C26 Contact Pace Customer Service for Assistance Problem Corrected 27 HS 150 CALIBRATION PROCEDURE INTRODUCTION The following procedure will enable the technician to accurately calibrate the control circuitry of the PACE HS 150 or HS 150E system Follow the procedure using the accompanying drawings as a guide System HS150 P N 7040 0002 PROCEDURE GENERAL DISSASSEMBLY 1 With the unit power turned off and unplugged from the AC supply and cooled off to room temperature remove the Top Cover Screws Remove the Top Cover from the unit ICAUTION KG HEA2. are routed on board via wire harness connected at J31 The board operates from dual complementary unregulated 14Vdc supplies and regulated 5Vdc The complementary 14Vdc and 14Vdc are produced by a 21 VCT transformer bridge rectifier and filter capacitors all off board and chassis mounted Regulated 5Vdc is produced on the 6020 0072 PPS 400 Microprocessor controller Board and routed onto the Multifunction Board at J31 5 The 21 VCT transformer secondary voltage center tap and chassis ground also route on board at J31 PULSE HEAT SECTION GENERAL Pulse Heat circuitry controls the operation of low voltage high current hand pieces such as Lap Flo and ThermoPart tools The circuit phase fires the line voltage primary winding of the Pulse Heat transformer only when the foot pedal selector switch is set to PH and the foot pedal is pressed The transformer secondary directly drives a Pulse Heat hand piece connected to front panel low voltage AC output terminals The effective handpiece power level is set by adjusting the Pulse Heat control potentiometer The Pulse Heat LED lights green whenever the foot pedal is pressed while the selector switch is set to PH If the Pulse Heat output of a power source is coupled to another unit s Pulse Heat output U10 Q25 and possibly the transformer may be damaged 10 MULTIFUNCTION PCB ASSEMBLY CIRCUIT OPERATION ZERO CROSSING DETECTOR Diodes CR 17 amp CR18 provide full wave rectification of
3. mode U5 3 if timed The high output from timer U4 8 is applied to inverter U7A and pin 5 of U7B U7A output is low turning on transistor Q6 through R80 and the green PASTE DISP LED through R78 The combination of logic high and low inputs at U7B produce high output at U7B 4 keeping Q7 and the red PASTE DISP LED off Hence the PASTE DISP LED is green indicating that a dispensing cycle is in progress 17 MULTIFUNCTION PCB ASSEMBLY MICROCHINE SECTION GENERAL The MicroChine section consists of circuitry that interfaces to and controls operation of the MicroChine handpiece and probe brake patch cord The Micro Chine section has a front panel control potentiometer for setting shaft rotational speed RPM a handpiece connector Probe Brake banana jack and Status LED The MicroChine handpiece is used for drilling milling probing and abrading operations CIRCUIT OPERATION CLOSED LOOP CONTROL CIRCUIT The MicroChine shaft speed is resolved by measuring the back EMF generated by the motor The motor is driven by pulse width modulated PWM voltage During each interval when the PWM motor drive voltage is off the motor coasts producing a back EMF or generator voltage The back EMF voltage is proportional to motor speed This generator voltage is scaled by the voltage divider comprising R42 and R43 and filtered by C21 When back EMF is generated CR2 is forward biased and the scaled diode offset back EMF signal applied to op amp Ul
4. quadrant three R11 is in series with the auxiliary triacs to limit the output current if a handpiece is plugged into the auxiliary outputs MICROPROCESSOR PCB ASSEMBLY RTD CONSTANT CURRENT SOURCE AND CHANNEL MULTIPLEXOR U9A makes up a constant current source that provides the current excitation for the RTD in the connected handpiece The current is multiplexed to one of six RTDs to be measured U9B amplifier feeds back the RTD voltage to modify the constant current source to correct for the non linearity of the RTD U11 is a dual eight channel multiplexor under control from the microcontroller Mux A Mux C signals The multiplexor will switch the constant current source to each of the RTDs and switch the RTDs voltage up to the analog to digital converter U10 CR9 and CR10 are in series with the multiplexor power inputs so that if the heater voltage feeds back onto the RTD input the voltage will be fed through the input diodes of the multiplexor and the power rail will float up to the input voltage and protect the chip U11 from damage Channel seven and eight of the multiplexor switch in the two very high precision calibration resistors every four minutes to allow the microcontroller to dynamically re calibrate the RTD measuring circuits R48 is the low calibration resistor 32 F and R50 is the high calibration resistor 987 F ANALOG TO DIGITAL CONVERTER UIO is a dual slope integrating analog to digital converter front end Under co
5. the main power transformer s center tapped secondary voltage The rectified voltage is applied to the voltage divider comprising R72 amp R69 after transformer phase shift compensation by C37 The voltage is divided down from about 10 VAC to 5VAC and applied to U6A 3 where it is compared to 316 mVdc at U6A 2 When the amplitude of the AC signal at U6A 3 is less than 316 mVdc U6A 1 output is low When the AC signal at U6A 3 rises above 316 mVdc U6A 1 output is high the net effect being the production of a train of narrow negative going zero crossover detection pulses at twice line frequency RAMP GENERATOR Each zero crossing pulse forward biases CR14 momentarily discharging C29 through R68 to a diode drop less that the buffered reference voltage from U6B 7 With C29 discharging the summing junction current imbalance at U6C 9 forces U6C 8 output high The output remains high until the zero crossover interval ends At that time current entering the summing junction at U6C 9 through R25 and C29 drives output U6C 8 low at a constant rate The result is production of a periodic ramp sawtooth waveform R61 U3A CR7 R20 R21 C23 and U3B drive U6C 9 through R25 compensating for line frequency differences and ensuring that U6C 8 output waveform transitions from near ground to the positive supply rail PULSE WIDTH MODULATION CONTROLLER AND LINE INTERFACE The ramp waveform from U6C 8 is applied to U6D 13 where it is compared against the Puls
6. which detects a handpiece or foot switch closure comprises R11 R54 Q1 and U7D The PROBE BRAKE latch output state is read by R76 R77 Q4 and U8A Active torque limiting circuitry is detected by the network consisting of CR20 R91 C39 and R90 During normal operation the torque limiter is off pulling low U8B 5 through R90 Since the probe brake is also off during normal operation Q4 is off and U8A inputs are pulled high through R77 driving U8B 6 low With both inputs low U8B 4 output is at a logic high keeping Q10 cut off and the red Status LED off 732 18 When the PROBE BRAKE latch is on base current flows through R76 turning on Q4 and pulling low U8A inputs and U7D 12 The low at U7D 12 drives U7D 11 high keeping Q8 cut off and the green Status LED J32 8 off The low inputs of U8A drive its output to a logic high U8B 6 is connected to U8A output The logic high applied by U8A to U8B 6 forces U8B out low turning on Q10 through R88 Q10 collector voltage turns on the red Status LED through R89 J32 18 and J32 26 When the PROBE BRAKE latch is off and torque limiting circuitry active Q15 collector voltage forward biases CR20 charging C39 through R91 The resultant logic high is maintained during PWM motor drive voltage off periods by the large time constant of C39 and R90 The logic high from C39 is applied to U8B 5 forcing its output pin low U8B 4 and turning on Q10 and the red Status LED The green status LED is on thro
7. 126 R127 and C52 snub switch transients and reduce EOS ESD in the system PASTE DISPENSER CIRCUIT OPERATION RECYCLE TIMER When the front panel selector switch is set to PD 14 Vdc is supplied to J32 24 J32 32 R65 and C19 are connected to J32 32 and oscillator timer IC U4 s pin is connected to the MODE and Q Q pins configuring the timer to output high initially after reset and to operate in the recycle mode C19 charges up and powers U4 each time the selector switch is set to PD U4 5 is grounded enabling auto reset and the chip resets all internal counters at power up U4 oscillator frequency is 8 7 Hz nominal and is set by R26 and C5 Time select inputs A and B are used to determine durations of low and high output at U4 8 The B time select input U4 13 is connected to ground The A time select input U4 12 is connected to the timer output U4 8 through R66 When a change of state occurs at the OUT pin U4 8 R66 and C24 delay the new voltage level s application to U4 12 the A time select input to allow for internal settling 14 MULTIFUNCTION PCB ASSEMBLY When power is applied to U4 the timer automatically resets itself and its OUT pin U4 8 goes high The B time select input is low and the A select input goes high due to its connection to U4 8 This combination of time select inputs along with MODE and Q Q inputs already discussed programs the timer to output high for 256 counts approxi
8. A 3 The op amp is configured as a voltage follower buffering the back EMF signal and applying it through R4 to the summing junction of error amplifier U1D 13 The summing junction detects differences between the back EMF signal and the control pot RPM setting R1 and R2 provide summing junction offset current compensation R2 is set at the factory during calibration The Variable Speed Control pot ends are connected in parallel with 18V zener diode CR11 at J32 1 and J32 31 The wiper voltage is routed on board via J32 28 and applied to R44 generating the set point current at the summing junction Whenever the summing junction detects that the motor speed is less than the setpoint U1D 14 output is driven high U1D output is applied to comparator U1B 5 through the network comprising R5 R10 C12 C13 CR3 and CR4 When the handpiece is just turned on R7 and C13 provide soft start of the motor by slowly charging up to the error voltage The divider consisting of R8 R10 and diodes CR3 and CR4 clamp UID output over a narrow voltage range limiting the error voltage This conditioned error voltage signal provides improved motor response to changing shaft load i e transients and produces a smoother PWM output when U1B 5 is compared to the triangle waveform at U1B 6 The triangle waveform at U1B 6 is produced by the ramp generator comprising UIC R47 R50 and C22 The signal is applied to U1B 6 through R41 and is a 300 Hz nominal signal varying f
9. ANGE INCORPORATED PRC 2000 2M SYSTEMS PC BOARD TROUBLESHOOTING amp HS 150 CALIBRATION PROCEDURE SERVICE MANUAL ADDENDUM MANUAL NO 5050 0365 REV B INTRODUCTION The following pages detail theory of operation and procedures for troubleshooting both the Microprocessor PCB and Multifunction PCB assemblies and calibration of the HS 150 system The included pcb troubleshooting Flow Charts will assist the technician in determining the source of a malfunction down to circuit area or component level If you should encounter any difficulty in trouble shooting the pc boards or calibrating the HS 150 contact PACE Customer Service at TEL 301 490 9860 FAX 301 604 9215 MICROPROCESSOR PCB ASSEMBLY THEORY OF OPERATION GENERAL DESCRIPTION The PACE part number 6020 0072 microcontroller Microprocessor board is the control for the Thermal Management Center section of the PRC2000 Repair center The main purpose of the board is to measure and control the handpiece temperature established by the operator Refer to schematic Microprocessor PCB Assembly Schematic in this manual or PACE drawing number 5000 0281 POWER SUPPLY The transformer secondary AC is rectified by the bridge rectifier and filters to 14 Vdc and 14 Vdc and fed into the board of J5 The 14 Vdc is fed into regulator Ul that regulates the voltage down to 5 Vdc The 14 Vdc is fed into regulator U2 which regulates it down to 5 Vdc ZERO CROSSOV
10. CR5 to U2A 2 temporarily raising its input voltage above the latch reference threshold voltage at U2A 3 This drives U2A output low reverse biasing CR6 and re establishing the 100 mVdc reference voltage at U2A 3 The MicroChine handpiece PROBE BRAKE feature is supported by EOS Chassis Ground being continuous with DC Circuit Ground through PTC1 This keeps the MicroChine shaft at ground potential for probing and provides fault protection in the event of a ground fault in the THERMAL MANAGEMENT CENTER TMC section of the unit Ifa ground fault causes the PTC to enter its high resistance state the PROBE BRAKE circuit and its Status LED will activate and or indicate In addition to the grounded shaft the MicroChine handpiece incorporates a bifilar wound choke and a transzorb to minimize EOS ESD transients 20 MULTIFUNCTION PCB ASSEMBLY STATUS LOGIC AND LED DRIVE CIRCUITS MicroChine operating status is indicated by a front panel mounted tri color Status LED MicroChine status is determined by the states of the handpiece and foot pedal switches the probe brake latch and the over current torque limiting circuit During normal operation either the MicroChine handpiece switch is closed or the front panel Foot Pedal Selector Switch is set to and the foot pedal switch closed lighting the Status LED green When the torque limiting circuitry is active the LED is amber The LED is red if the probe brake latch is on The status circuit
11. ER DETECTOR Comparator U8D is used as a zero crossover detector AC voltage from the transformer is rectified by diodes CR3 and i N 3 N a CR4 to produce a rectified unfiltered voltage signal at U8D A V pin 11 Fig I signal A Signal is compared with reference voltage to produce low going signal at the time period that the AC voltage is crossing zero volts Fig I B Signal B Signal B at U8D pin 13 is the zero crossover signal that is used to enable the triggering circuits of the triacs at the zero crossover point Figure 1 Zero Crossover Detector RESET WATCHDOG AND BROWNOUT CIRCUITS Comparator U8B is used as the reset and brownout detector When power is first turned on the unregulated 14 Vdc charges C23 through R37 until voltage on C23 passes the 2 Vdc ref voltage at U8B pin 6 The output of U8B pin 1 will then go high and turn off Q4 which will remove the reset from the microcontroller If the unregulated 14 Vdc falls below 6 8 Vdc the U8B will detect a brownout condition and continuously apply a reset to the microcontroller Comparator U8A along with Q3 comprises the watchdog circuit The microcontroller will supply a pulse stream out of U3 pin 17 if the program is executing properly If the program fails the pulse stream will stop pulsing Q3 on and allow C21 to discharge causing U8A output pin 2 to go low and turn on Q4 resetting the microcontroller When the reset
12. Gon amp Rid WORKING AUX CHECK Q20 CHANNEL 2 Q24 amp R16 WORKING 3 NOT WORKING CHECK Q19 Q23 amp R15 Figure 2 MicroProcessor PCB Troubleshooting Cont d 8 MICROPROCESSOR PCB ASSEMBLY PAGE 3 OF 3 FROM PAGE 2 IS CHECK I Q1 Q17 CR8 HORINGS R12 R13 amp R56 CHECK BUZZER OSC CIRCUIT U8C BUZZER DRIVER TRANSISTOR Q21 amp BUZZER LS1 WORKING CHECK ERROR RTD CONSTANT NUMBER ON CURRENT SOURCE DISPLAY OR CHANNEL MULTIPLEXER amp ANALOG TO DIGITAL CONVERTER IS CHECK MICROCONTROLLER AND KEYBOARD CONNECTOR CONTACT PACE CUSTOMER SERVICE FOR ASSISTANCE YES Figure 2 MicroProcessor PCB Troubleshooting Cont d MULTIFUNCTION PCB ASSEMBLY THEORY OF OPERATION GENERAL DESCRIPTION The PACE Multifunction Board P N 6020 0074 is used in the PPS 400 power source to provide status and control for Pulse Heat Pulse Plate Paste Dispenser Pik Vac and MicroChine functions The board interfaces to front panel controls and indicators via wire harnesses It also interfaces to power supply voltages the Pulse Heat transformer Pik Vac vacuum pump and Paste Dispenser motor pump assembly Refer to Multifunction PCB Assembly Schematic amp Wiring Diagram of this manual or PACE schematic 5000 0283 and wiring diagram 5000 0284 for circuit and interconnect information when reading this document POWER SUPPLY All supply voltages
13. TED SURFACE DO NOT TOUCH Em zA ae To D Cover Screw Jack Control Sviten Switc p r Plate HotSpot 5 5 BED 22 PLATE PROBE tO D L Probe Plate Control Switch Front Figure 7 HS 150 Parts Identification 2 Disconnect the two White varglass sensor leads from the White Orange and White Gray leads refer to Figure 8 28 HS 150 CALIBRATION PROCEDURE PLATE TEMPERATURE CONTROL 3 Connect a 177 47 ohm resistance between the White Orange and White Gray lead and monitor the voltage of the White Gray lead with respect to the White Orange lead This voltage will be called V1 4 Move the shorting block on J14 pins 2 and 3 to J14 pins and 2 refer to Figure 8 White Black White Red White Brown Whit 22 TL NN 2222 2 22241 2222222 5221 222225225241 22222222222 5 Turn the Plate Control and Probe Control knobs the front panel completely counter clockwise refer to Figure 7 6 Plug the power cable into the AC supply and turn the Power Switch on 7 Monitor the voltage at TP1 refer to Figure 8 with respect to the White Orange lead This voltage will be called V3 8 Adjust R36 until voltage V3 reads SmV
14. ase through R108 turning on Q13 Q13 keeps Q14 off clamping its base near ground With Q14 off Q22 base is pulled high through R105 and R109 cutting off the motor driver transistor virtually as soon as the switch is released OVER CURRENT DETECTOR TORQUE LIMITER Motor torque is monitored and limited by the over current detector torque limiter This circuit comprises R113 R110 R114 C47 Q15 R39 and CR1 Motor drive current flows through current sense resistor R113 Instantaneous voltage drop develops across R113 proportional to instantaneous current draw of the MicroChine handpiece motor The voltage across R113 is averaged by C47 and R110 Q15 acts as a comparator with a threshold of approximately 0 6 volts If high motor torque develops due to overload the average voltage across C47 reaches 0 6 volts and Q15 turns on The collector voltage of Q15 forward biases gating current through R39 to the error amplifier summing junction U1D 13 The amplifier output then signals the pulse width modulator to slow down the motor reducing motor drive current and torque 19 MULTIFUNCTION PCB ASSEMBLY MICROCHINE SECTION CONT D PROBE BRAKE CIRCUIT The PROBE BRAKE circuit comprises C2 C3 C16 C17 CR5 CR6 R15 R17 R19 R57 R60 R128 U2A and U2B A voltage divider consisting of R17 and R18 provides low voltage low current safe excitation of a workpiece connected to a test lead plugged into the front panel PROBE BRAKE Receptacle Th
15. d U5 3 are low The low from U4 8 is applied to inverter U7A which outputs high keeping transistor Q6 and the green LED off U5 3 low output is applied to inverter U8C through R32 driving U8C 10 high The high is applied to U7B 6 The remaining input terminal is fed a low by U4 8 driving U7B 4 high turning off Q7 and the red LED If the Foot Pedal Selector Switch is set to PD for paste dispensing but the foot switch is open and the pump is recharging the air reservoir U4 8 output is high and U5 3 output is low U4 8 high output is inverted by U7A producing a low at U7A 3 turning on Q6 through R80 Q6 turns on the green PASTE DISP LED through R78 Concurrently U8C inverts U5 3 low output driving U8C 10 high The resultant high at U7B 6 paired with the high at U7B 5 from U4 8 drives U7B 4 low This low output turns on Q7 through R82 Q7 turns on the red PASTE DISP LED through R84 Since the red and green PASTE DISP LEDs are both on and contained within the same T1 3 4 package the LED lights amber indicating that the pump is recharging the reservoir In the event that the foot pedal is pressed in either the timed or continuous operational mode a high is applied to inverter USC In continuous mode the high is produced by Q9 05 3 drives the inverter through R32 in timed mode The high input at inverter U8C produces low output which is applied to U7B 4 U4 8 is driven high by application of a high at its master reset input from Q9 if continuous
16. e Heat control voltage set point The set point voltage is applied to U6D 12 if the foot switch is closed When the foot switch is first closed R71 amp C36 slowly charge U6D 12 to the set point voltage providing transformer soft start The set point voltage is compared against the ramp waveform at U6D 13 providing pulse width modulated output at U6D 14 The pulse width modulated output of U6D 14 drives U10 1 through current limiting resistor R70 Snubber R103 amp C35 attenuate foot switch generated EOS ESD transients CR22 protects the optocoupler LED from switching transients that exceed its reverse voltage rating U10 triac conducts when the input LED is active turning on power triac Q25 R122 amp R123 provide gate current limiting When Q25 turns on line voltage at J34 1 is switched to the Pulse Heat transformer via J34 2 C50 C51 R124 and MOVI protect the triac circuit from false triggering or breakdown due to line transients 11 MULTIFUNCTION PCB ASSEMBLY PULSE PLATE SECTION GENERAL Pulse Plate circuitry controls operation of SwaPlating electrodes The Pulse Plate section of the front panel has two banana jacks to accommodate plating electrodes a control potentiometer for setting electro cleaning amp plating voltages and an LED to indicate status CIRCUIT OPERATION PLATING VOLTAGE Diodes CR23 amp CR24 provide full wave rectification of the main power transformer s center tapped secondary voltage 10 5VAC1 a
17. e front panel jack is connected to the divider via wire harness conductor terminating at J32 27 R128 provides input protection of buffer U2B The 200 mVde divider voltage is buffered by U2B and applied to probe brake latch U2A through R60 Another voltage divider comprising R19 R58 and R59 applies a 100 mVdc reference voltage to U2A 3 The latch output U2A 1 is low and remains at that level until the J32 27 is pulled down below 100 mVdc Ina typical application this occurs when the MicroChine tip contacts the PROBE BRAKE test lead or part of a workpiece to which it is connected When the PROBE BRAKE input is pulled below the 100 mVdc reference of the latch it is applied through buffer U2B and R60 to U2A 2 the latch trigger input The latch output goes high driving CR6 into conduction and shifting the latch reference voltage well above the 200 mVdc excitation normally applied by the buffer Through this action U2A output is latched high even if the workpiece is disconnected from the PROBE BRAKE Receptacle The latch is cleared by first allowing the excitation voltage to return to its 200 mVdc nominal value Typically this is done by lifting the MicroChine handpiece away from the workpiece breaking contact between the PROBE BRAKE excitation voltage and ground Ground is provided by any metallic MicroChine tip since the handpiece shaft is grounded Secondly the handpiece or foot switch must be released momentarily coupling a high through C16 and
18. g to Digital converter FLOW CHARTS The following Flow Charts should be used to determine the source of the Microprocessor board malfunction down to a circuit area or component level 6 MICROPROCESSOR PCB ASSEMBLY PAGE 1 OF 3 IS DISPLAY FLASHING WITH NO ERROR NUMBER DO WE HAVE ANY DISPLAY DO WE ONLY HAVE A PARTIAL DISPLAY CHECK CHECK CHECK IS SEGMENTS CATHODE S POWER SUPPLY WATCHDOG MISSING IN ALL US amp U6 CIRCUIT DIGITS AND CURRENT RESISTOR RNS CHECK IS IS DIGIT POWER SUPPLY CORAM DIGIT ONE ONE DRIVER Ok BAD TRANSISTOR Q14 CHECK CHECK MICRO IS DIGIT CONTROLLER DIGIT TWO TWO DRIVER RESET US BAD TRANSISTOR PIN 9 HIGH Q15 CHECK IS MICRO REPAIR IS DIGIT BEING RESET OR DIGIT THREE THREE DRIVER RESET WATCHDOG BAD ANSIST CIRCUIT TR HA oR CHECK LEDs REPAIR DRIVER MICRO TRANSISTOR CONTROLLER Q13 DIGIT 4 Figure 2 MicroProcessor PCB Troubleshooting MICROPROCESSOR PCB ASSEMBLY PAGE 2 OF 3 IS ALL CHECK OUTPUT ZERO CHECK TRIAC OF ZERO LATCH U7 CHANNELS CROSSOVER CROSSOVER AND TRIAC T HEATING NOT HEATING CIRCUIT WORKING DRIVER U6 DO HANDPIECES HEAT FROM PAGE 1 CHECK REPAIR ZERO CO TO PAGE 3 CHANNEL 1 Q5 Q6 Q2 CROSSOVER WORKING R4 amp R5 CIRCUIT CHANNEL 2 WORKING CHECK CHANNEL 3 010 011 012 WORKING R9 amp R10 AUX CHANNEL 1
19. high the microcontroller will reset the pump state to off pin 13 held high Although Q1 may fail 1f the handpiece shorts and AC voltage is fed into the switch input the zener diode CR8 will protect the microcontroller BUZZER U8C comparator forms a 2 05K Hz square wave oscillator that drives Q21 which in turn drives the audio transducer LS 1 at its resonant frequency The driver is controlled by the microcontroller U3 pin 11 holding the base of Q21 low to turn it off The RESET will also hold the driver transistor Q21 off through CR5 TRIAC DRIVER Output to the triac drivers takes place on the back edge of the fourth digit display signal Before turning off the digit four display the data on port two of the microcontroller is changed to the triac data and then turns digit four off signal going high which clocks the triac data into U7 U7 is an eight bit latch that holds the triac information The output of the latch is enabled with the zero crossover signal which allows any output that has a high latch within to turn on the associated triac The microcontroller U3 output from pin 10 will allow the microcontroller to turn off all triacs at once through The high signals from U7 drive inverter U6 to turn on the transistors that drive the current into the gates of the triacs Each power triac driver has two drive transistors to allow the triacs to be triggered from a negative voltage so that the trigger will be in quadrant two and
20. higher than voltage VI 9 Position the Probe Plate Switch to Plate refer to Figure 7 10 Position the C F Switch to C refer to Figure 7 11 Connect a114 68 ohm resistance between the White Orange and White Gray leads 12 Adjust R35 until the display reads 38 13 Position the C F switch to F 14 Adjust R34 until the display reads 100 15 Connect a 177 47 ohm resistance between the White Orange and White Gray leads 16 Postion the C F switch to C 17 Adjust R37 until the display reads 204 White Orange 18 Position the C F Switch to F ee 19 Adjust R38 until the display reads 400 20 Repeat steps 10 through 19 until there is no change in Figure 8 HS 150 PC Board the display at the calibration points If Probe Temperature Control calibration is not needed skip to step 25 29 HS 150 CALIBRATION PROCEDURE PROBE TEMPERATURE CONTROL 21 Verify that a 177 47 ohm resistance is connected between the White Orange and White Gray lead and monitor the voltage of the White Gray lead with respect to the White Orange lead This voltage will be called V1 22 Verify that the Plate Control and Probe Control knobs on the front panel are completely counter clockwise refer to Figure 7 23 Using a 3 5 mm plug connect a 177 47 ohm resistance into the probe jack refer to Figure 7 Monitor the voltage across the resistance center conductor with respect to the ground conductor Thi
21. ions the average DC load current is typically less than 400 mA STATUS LOGIC AND LED DRIVE The status logic and Led drive circuit comprises U9 Q5 Q11 Q12 R92 R99 C33 CR21 J32 7 J32 19 and J32 20 The Pulse Plate LED lights when the front panel selector switch is set to PP and the foot switch closed During normal plating operation Q5 is off and U9A 2 is pulled up to 14 V through R93 driving U9A 3 low The low output is applied to U9B 5 through R94 driving U9B 4 inverter output high The inverter output drives Q12 base through R97 turning off Q12 and the red LED at J32 20 The inverter output also is applied to a second inverter U9C 8 which outputs low at U9C 10 turning on 011 through R96 In the on state Q11 turns on the green Pulse Plate LED through R99 In the event of an over current condition the foldback current limiting circuit activates and Q19 is on driving Q5 base through R92 Q5 turns on pulling U9A 2 low U3D 14 PWM output is applied to U9A 1 The low portion of U3D 14 PWM output drives U9A 3 high High output from U9A forward biases CR21 rapidly charging C33 through R95 The resultant high at U9B 5 drives U9B 4 output low The low signal turns on Q12 through R97 and the red Pulse Plate LED through R98 The low signal is also applied to inverter U9C 8 turning off Q11 and the green Pulse Plate LED During the high portion of the PWM signal U9A 3 is low and CR32 is blocking C33 begins slowly discharging toward gr
22. is applied to the microcontroller R3 provides a feedback into the watchdog circuit to turn on Q3 and release the reset so that the microcontroller may restart its program MICROPROCESSOR PCB ASSEMBLY DISPLAY DRIVER The LED display is multiplexed under software control The power is supplied to the anodes for about 2 8 ms out of the 11 11 ms from the driver transistors Q13 Q16 The driver transistors are controlled from pin 36 through pin 39 of U3 microcontroller The information for the cathodes of the display is supplied through driver U5 and U6 10 with the current limited by RN5 Information to the cathode s drivers is supplied from the microcontroller port 2 U3 pin 21 28 VACUUM PUMP DRIVER The vacuum pump driver is comprised of transistors Q1 and Q17 which are controlled from both the microcontroller U3 pin 13 and the handpiece switches When a switch is activated low base current will flow through Q1 base and R13 QI will turn on which in turn will turn on Q17 applying power to the motor of the pump At the same time the voltage at U3 pin 13 will go low letting the program know that a switch has been activated The program will let the motor run at 28 Vdc for 150 ms and then it will start chopping the voltage at a 2KHz rate by bringing pin 13 low and cutting off the base voltage of Q1 When the switch is released the microcontroller will read pin 13 between chops to see if the pin is not being held low by the switch if pin 13 is
23. mately 14 seconds After 256 counts the output goes low selecting U4 s internal ripple counter output for 8192 counts Since 256 counts already have occurred in the internal ripple counter the timer outputs low for the number of counts remaining to reach 8192 7936 counts approximately 7 minutes and 36 seconds Thereafter the cycle automatically repeats itself The output goes high for 14 seconds outputs low for 456 seconds then repeats This cycle will continue until the front panel selector switch is set to a position other than PD or the paste dispenser is activated by foot switch closure in either the timed or continuous mode thereby forcing a reset through U4 s MR master reset pin U4 6 PASTE DISPENSER PUMP DRIVE The paste dispenser pump operates from two motor voltages The motor is started with full 28 Vdc This kick start voltage provides the additional power required by the motor when starting up against a pressurized pump and reservoir The duration of the motor kick start interval is established by C38 and R85 After the kick start interval ends 28 Vdc is replaced by a pulse width modulated run voltage This voltage operates the pump after motor start up The run voltage is 11 Vdc avg The paste dispenser pump operates whenever U4 8 is at a logic high When U4 8 output transitions high the signal is applied directly to U7C 8 and coupled through C38 to U8D 13 via R86 C38 and R85 establish the du
24. mp 10 5VAC2 respectively The resultant unregulated unfiltered pulsating DC is used by the Pulse Plate circuit to perform electro cleaning and plating functions PWM CONTROLLER U3D is the Pulse Plate setpoint comparator The same periodic ramp waveform saw tooth used for Pulse Heat PWM control is fed to U3D 13 and compared to the U3D 12 setpoint voltage When the front panel selector switch is set to PP and the foot switch open the control potentiometer CW terminal J32 16 floats applying 14 Vdc as the setpoint voltage and forcing U3D 14 output high When the foot switch is closed the control potentiometer CW terminal is grounded and the pot wiper voltage is applied to U3D 12 as the setpoint voltage Lower setpoint voltages increase the time the output is low i e higher duty cycle during the ramp waveform period Low output at U3D 14 forward biases CR8 turning on Q24 through current limiting resistor R23 While Q24 is on pulsating DC current flows through the transistor out to the load via connector J33 the front panel and DC output jacks and the SwaPlating tools Normal load current flows unless there is a short circuit 12 MULTIFUNCTION PCB ASSEMBLY FOLDBACK CURRENT LIMITING Foldback current limiting is provided by the circuit comprising R118 R119 R120 R121 C49 CR26 Q18 and Q19 The typical knee value where foldback current limiting occurs is 3 4 A DC average Under short circuit condit
25. mp Waveform at U3D Pin 13 Is U3D Pin 14 Logic High Replace U3 Check Q24 amp Check CR8 Check Ramp Circuit R121 R23 amp Q18 U3 amp U6 Contact Pace Customer Service for Assistance Problem Corrected Figure 4 Pulse Plate Troubleshooting 23 MULTIFUN MICROCHINE CHECK WRING SUPPLY VLTG MICROCHINE RUNS DOES SWITCHES CONTINUOUSLY W O MICROCHINE HNDPC BEFORE SWITCH PROCEEDING a MICROCHINE LED ON CHECK STATUS LOGIC CIRCUITS 01 Q4 Q8 Q10 U7D U8A CHECK Q22 5 088 amp 025 IS U1D PIN 14 A LOGIC LOW IS 10 PIN 13 A LOGIC HIGH REPLACE U1 IS U2A PIN 1 RELEASE A LOGIC HIGH MICROCHINE SWITCH RAMP WAVEFORM AT UIC PIN 9 CHECK C22 amp Ul U1B PIN 7 ALWAYS LOW CHECK CRIO amp 013 014 022 amp CHECK U2 R113 CIRCUITS CR6 amp C16 Figure 5 MicroChine Troubleshooting 24 MULTIFUNCTION PCB ASSEMBLY CHECK Q4 Q10 Q15 U8A amp U8B LED COLOR MICROCHINE SPEED CONTROLLED MICROCHINE TRANSIENT RESPONSE OK CHECK CRI amp CHECK C13 G ato UT oss Q15 CR3 amp CR4 amp 08 PROBE BRAKE STATUS LED WORKS OK CONTACT PROBLEM CORRECTED 25 MULTIFUNCTION PCB ASSEMBLY PASTE DISPENSER e Supp Does P Is LED with
26. ntrol from the microcontroller ADC A and ADC B signals the dual slope converter will integrate the input for 16 6 ms into C25 and time the deintegration to the reference voltage The microcontroller will then use the two times and the reference voltage to calculate the temperature of the RTD KEYBOARD INPUTS The microcontroller U3 drives the keyboard directly by providing the row drive low signal to the keyboard out of pin 1 and pin 2 After a row has been selected the microcontroller will read the keyboard data from pins 3 4 and 5 EEPROM MEMORY U4 1s a 1024 bit Serial Electrically Erasable Programmable Memory The microcontroller U3 interfaces with the memory through a serial interface using U3 pin 14 to select the memory chip U3 pin 15 to clock the data into the chip and pin 16 to supply and read the data MICROPROCESSOR PCB ASSEMBLY ERROR CODES There are certain error codes that may show up on the Digital Readout display if the program detect a fault within the system These Digital Readout errors are listed below with the probable cause fault and the probable repair solution 1 in the middle of the Digital Readout This error indicates an error on power up when the system program is checking the Random Access Memory or when comparing the sum check against the store sum check The microcontroller U3 will require replacement 2 E 1 on the Digital Readout This error indicates that the system pr
27. ogram has detected a high resistance on the sensor input RTD open Check the handpiece J1 connector RTD Constant current source channel multiplexor and Analog to Digital converter 3 E 2 on the Digital Readout This error indicates that the system program has detected a low resistance on the sensor input RTD shorted Check the handpiece J1 connector RTD Constant current source channel multiplexor and Analog to Digital converter 4 E 3 on the Digital Readout This error indicates that the system program has detected an RTD resistance on the sensor input greater then the referenced resistance for 1000 F but less then the resistance required to cause an E 1 error Digital Readout overflow Check the handpiece J1 connector RTD Constant current source channel multiplexor and Analog to Digital converter 5 E 4 on the Digital Readout This error indicates that the system program has detected an RTD resistance on the sensor input lower than the referenced resistance for 32 F but higher than the resistance required to cause an E 2 error Digital Readout underflow Check the handpiece J1 connector RTD Constant current source channel multiplexor and Analog to Digital converter 6 E 5 on the Digital Readout This error indicates an incorrect resistance for the calibration resistors R48 and R50 Check the calibration resistors R48 and R50 RTD Constant current source channel multiplexor and Analo
28. ound through R94 The large time constant of C33 and R94 ensure that a logic high is maintained at U9B 5 throughout the remainder of the period of U3D 14 PWM output The high at U9B 5 keeps the red Pulse Plate LED on as described above When the over current condition is removed the foldback current limiting circuit turns off Q5 turns off and the green Pulse Plate LED lights again as described above 13 MULTIFUNCTION PCB ASSEMBLY PIK amp PASTE SECTION THEORY OF OPERATION GENERAL The Pik amp Paste section consists of circuits that control operation of the Pik Vac vacuum pump and the Paste Dispenser paste pump and solenoid valve The Pik Vac has an on off switch LED and vacuum fitting for a component pick up hand piece vacuum wand The Paste Dispenser has a switch for selecting timed or continuous dispensing a control potentiometer for setting dispensing time a status LED and quick connect fitting for connection of a syringe containing solder paste adhesive or other material PIK VAC CIRCUIT OPERATION The Pik Vac pump is connected between J31 8 and J31 2 and operates from 21 VAC The pump operates when the front panel Pik Vac switch is closed completing the circuits connecting the pump and Pik Vac LED and the 21 VCT transformer secondary With the Pik Vac switch closed 21 VAC is rectified by CR27 turning on the green Pik Vac LED through current limiting resistor R125 CR27 provides LED reverse voltage breakdown protection R
29. ration of the motor kick start interval The high at U8D 13 drives U8D 11 low turning on Q20 through R83 Current flows through Q20 collector out to the paste pump connected between J31 12 and J31 10 The pump is driven with approximately 28 Vdc The low output from U8D 11 also routes to U7C 9 With both input terminals at different logic levels U7C output is driven high The high signal charges C4 through R24 When C4 charges up U3C 9 will momentarily go a little more positive than U3C 10 forcing U3C 8 low When R85 has discharged C38 to near ground 40ms nominal the combination of logic low signals at U8D input terminals drives U8D 11 high turning off Q20 and the paste dispenser pump The high output from U8D is applied to U7C 9 forcing U7C 10 low U7C 10 low output discharges C4 through R24 and R64 When the voltage across C4 drops to a little less than that at U3C 10 U3C 8 again goes high The high is applied to U8D 12 driving U8D 11 low The low at U8D 11 provides base drive through R83 to Q20 turning on the paste pump R24 C4 and R64 will continue charging and discharging in this manner so long as U4 8 output is high This provides PWM control of Q20 and the pump The duty cycle is approximately 40 with a PWM frequency of about 6kHz The pump voltage is about 11 Vdc avg 15 MULTIFUNCTION PCB ASSEMBLY CONTINUOUS MODE OPERATION When the TIMED CONT switch is set to CONT and the FOOT PEDAL selector switch to PD pressing
30. rom 8V to 2V As the error voltage at U1B 5 increases so does the width of the positive going pulses at the comparator output U1B 7 The comparator output is clamped by CR10 providing Q14 base emitter junction reverse breakdown voltage protection When the comparator output is high it provides base drive to Q14 through R51 Ifthe MicroChine handpiece switch is closed or the Foot Pedal Selector Switch is set to MC and the foot pedal switch closed Q13 is off and does not clamp Q14 base to ground Thus Q14 is permitted to turn on each time positive going PWM pulses are applied unless the PROBE BRAKE latch is activated 18 MULTIFUNCTION PCB ASSEMBLY The PROBE BRAKE latch output U2A 1 must be low for the MicroChine handpiece to run The MicroChine motor runs when the handpiece switch is closed or the Foot Pedal Selector Switch is set to and the foot pedal switch closed When neither switch is closed and the PROBE BRAKE latch is off U2A 1 output is low a 5V control signal is applied through R16 and R13 to Q2 base turning on Q3 and forcing U1D 14 output low This shuts down PWM output from U1B after a slight delay due to slew rate and integrator effects and thus the motor drive transistor Q22 The motor control signal also biases Q16 on through R111 Q16 turns on Q17 through R115 Q17 turns on brake transistor Q23 through R117 braking the free wheeling motor when the switch is released The control signal also is applied to Q13 b
31. s voltage will be called V2 24 Adjust R39 until voltage V1 matches voltage V2 5 mV GENERAL ASSEMBLY 25 Turn unit off and unplug 26 Reconnect the white varglass sensor leads to the White Orange and White Gray leads 27 Move the shorting block on J14 pins I and 2 to J14 pins 2 and 3 28 Apply glyptol or other like locking substance to trimpots 1 through 6 29 Remount the Top Cover to the unit using the 2 Top Cover Screws removed in step 1 30
32. the foot pedal makes a closure to ground at J32 17 turning on Q9 through R87 Q9 collector goes high providing base drive through R107 to solenoid driver transistor Q21 Q21 turns on activating the solenoid valve connected between J31 13 and J31 14 by providing a path to ground The NC valve opens gating the paste dispenser pump and reservoir air supply to the front panel PD quick connect Concurrently the high at Q9 collector is applied to timer U4 6 master reset input through R28 resetting the timer The timer output goes high initiating PWM drive of the paste dispenser pump as previously described As long as the foot pedal switch is pressed the closure to ground at J32 17 is maintained and the pump and solenoid valve are active When the foot pedal switch is released the high reset signal is removed from U4 6 and timer output U4 8 is high for 14 s driving the pump and recharging the reservoir TIMED MODE OPERATION When the TIMED CONT switch is set to TIMED and FOOT PEDAL selector switch to PD pressing the foot pedal makes a closure to ground at J32 29 The resultant low is coupled to the trigger input U5 2 of the 7555 timer through C7 The timer output terminal U5 3 goes high turning on the solenoid valve by driving Q21 base through R32 and R107 U5 3 high output also turns on the paste dispenser pump by driving its master reset input U4 6 through R32 and R28 The 7555 timer output remains high driving the p
33. ugh the same circuit operation described for normal operation The combination of simultaneously lit green and red Status LED produces an amber color The Status LED is off if the PROBE BRAKE latch and handpiece are off 21 MULTIFUNCTION PCB ASSEMBLY FLOW CHARTS The following Flow Charts should be used to determine the source of the Multifunction board malfunction down to a circuit area or component level Locate the chart that best describes the malfunction PULSE HEAT Check Wiring Supply Voltage Switches amp Hndpc Before Proceeding Set Front Panel PH Pot Fully Clockwise and Press Foot Pedal Is Output Is Half Output O Check U6D Cycling Vac Adjust Pot Check Fram CW t Check CRI7 USB USC CCW While CRIB amp Measuring PH Q25 en Output Voltage Does Output Vary Check U6C From 0 to 2 3 U6D amp U9D Vac Contact Pace Customer Service for Assistance LED Problem Check PH LED amp Connections Problem Corrected Figure 3 Pulse Heat Troubleshooting 22 MULTIFUNCTION PCB ASSEMBLY PULSE PLATE Check Wiring Supplies Switches Before Proceeding PP LED Drive Voltage Output Problem Check Foot Pedal U9 Q5 Q11 Pressed amp Q12 Circuits Q18 Emitter Voltage 9VDC Avg Foot Pedal Pressed Check CR23 amp CR24 Base Drive at Q24 Foot Pedal Pressed Is Ra
34. ump and solenoid valve circuits for the time established by the resistance setting of a logarithmic pot between terminals J32 14 and J32 34 The 7555 timer s chief function is to provide timed gating of air to the attached dispensing hand piece by accurately controlling its ON time The timer output initiates paste dispenser pump turn on at the same time as the solenoid valve but once the 7555 timer output goes low and the solenoid valve closes the paste dispenser pump continues to run for approximately 14s to replenish the reservoir The pump will periodically recycle automatically recharging the reservoir Dispensing only can occur when the solenoid valve is activated and that occurs only when the foot pedal has been pressed R102 establishes a minimum on time when the log pot is set to its minimum resistance value The trigger circuit comprises snubber R33 amp C8 and the trigger network of R30 C7 and R31 R34 C25 and CR13 form a power on reset circuit R35 R38 is a network with factory set pot to improve timer accuracy by shifting the 7555 timer internal switching threshold 16 MULTIFUNCTION PCB ASSEMBLY STATUS LOGIC AND LED DRIVE CIRCUITS Paste dispenser status is determined by logic gates U7A U7B and U8C R78 R80 R82 R84 Q6 and Q7 provide Status LED drive There are three status conditions LED off LED green LED amber When the Paste Dispense section is not selected or the pump is idle and not recharging U4 8 an
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