Ericsson PF 768 Troubleshooting Instructions Download

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Approved according to 2/FEA 209 544

Trouble-shooting
instruction

PF 768

Service Manual by Toko

4/00021-2/FEA 209 544/11.C

PF768, Standard Electrical Repairs

Summary of Contents for PF 768

Page 1: ...Approved according to 2 FEA 209 544 Trouble shooting instruction PF 768 Service Manual by Toko 4 00021 2 FEA 209 544 11 C PF768 Standard Electrical Repairs...

Page 2: ...eviations 4 1 3 Pin placements 6 2 No serv not able to connect calls 8 3 Doesn t start 11 4 Audio 21 5 Display 29 6 SIM Insert card 33 7 Keyboard 37 8 Illumination and buzzer 42 9 RTC 50 10 Component...

Page 3: ...is affected when replacing it Class A and B A test call towards the real net not only towards a GSM test instrument and run it through the normal tests is enough to verify the functionality since the...

Page 4: ...DCON Logical signal from the processor that keeps the phone running after you ve released the On Off key EXTAUD Input signal at the system connector that the processor uses to deter mine if there s a...

Page 5: ...N800 VBATT Battery voltage VDIG DC voltage for the processor and memory VDSP DC voltage for the DSP Digital Signal Processor VLCD DC voltage for the display that controls the contrast VRAD DC voltage...

Page 6: ...1 3 Pin placements Single diode PIN diode Electrolytic capacitor Double diode or single trans stor Five pin circuit usually volt age regulator Double transistor Eight pin circuit Tx VCO circuit G300 L...

Page 7: ...PF768 Standard Electrical Repairs 4 00021 2 FEA 209 544 11 C 7 68 N800 D900 D600 D620 D610...

Page 8: ...ection 2 2 If the phone gets serv proceed to section 2 3 2 2 The phone doesn t get serv Open the phone and check for liquid damages Make sure the back cover is intact and that it s of the right model...

Page 9: ...y again Note that there are several different models of the antenna connector too and it s important to mount the correct one If you where able to connect a call proceed to section 2 4 The fault is pr...

Page 10: ...Bm input signal strength then the fault is Rx related Open the phone and check for liquid damages Make sure the back cover is intact and that it s of the right model since there are two models availab...

Page 11: ...charge send the phone to the next level If the phone starts lights the background illumination asks for SIM or PIN seeks net and the charging function is ok then there s probably nothing wrong with t...

Page 12: ...3 3 3 Current consumption with the On Off key pressed Insert a dummy battery into the phone If the phone consumes current immediately proceed to section 3 4 1 Start the phone by pressing the On Off ke...

Page 13: ...in the flash programmer If the phone doesn t start in the flash programmer proceed to section 3 4 5 If you can program the phone but it doesn t start afterwards or if the phone is troublesome in the f...

Page 14: ...PF768 Standard Electrical Repairs 4 00021 2 FEA 209 544 11 C 14 68 Fig 3 3 Fig 3 4 shows the measuring point for VANA and VDSP Fig 3 4 Fig 3 5 shows the measuring point for VRPAD and VVCO Fig 3 5...

Page 15: ...from one of the regulators or from V704 V708 or V709 fig 3 4 if there s no voltage at V702 pins 2 and 3 Replace a component at a time and check after every component replaced If there s voltage at bo...

Page 16: ...or oxidised Place the board in the fixture Keep it running by keeping DCIO high Check the VDIG VANA and VDSP voltages 3 2V fig 3 3 and 3 4 If any of the voltages are too low measure the resistance fr...

Page 17: ...he circuits fed by VBATT Send the phone to the next level If the fault remains send the phone to the next level 3 4 4 The phone runs as long as the On Off key is pressed Open the phone and check for l...

Page 18: ...oil damage and the phone is to be discarded Fig 3 8 If the fault remains send the phone to the next level 3 4 5 Doesn t start in the flash programmer Open the phone and check for liquid damages Make s...

Page 19: ...correct send the phone to the next level If the VRPAD voltage is too low measure the resistance from it to ground 25 kohms If the resistance is correct replace N452 class A If the resistance is too lo...

Page 20: ...s all of them 3 8V Note that P501 is a calibration point It is VRAD you measure but after 2 resistors The calibration point has the right voltage as long as the transmitter isn t activated Also note t...

Page 21: ...ow or no sound in the reference phone proceed to section 4 3 If both the microphone in the phone and the microphone of the handsfree don t work send the phone to the next level If both the microphone...

Page 22: ...PF768 Standard Electrical Repairs 4 00021 2 FEA 209 544 11 C 22 68 Fig 4 1 Check the solderings of N800 fig 4 3 Fig 4 2 Fig 4 3 If the fault remains send the phone to the next level...

Page 23: ...hone again If the fault remains measure the resistance of C850 and C851 both 100 kohms class A fig 4 3 Measure the resistance of R816 470 ohms fig 4 4 class A R817 and R819 1 kohms class A fig 4 3 Che...

Page 24: ...th sides of R605 and at D600 pin 67 5V fig 4 5 and 4 2 you follow the EXTAUDI signal If the voltage at only one side of R601 or R605 is too low replace the corre sponding resistor fig 4 3 and 4 5 both...

Page 25: ...efully and measure again If the resistance still is too low remove R605 class A fig 4 5 and measure again If the resistance increased replace D600 class B fig 4 2 If the resistance didn t increase or...

Page 26: ...the system connec tor pads X602 1 2 and 4 fig 4 6 Measure the resistance of C850 and C851 both 100 kohms fig 4 3 class A Make sure all the components in fig 4 7 R830 R825 R802 R805 C835 C810 and C812...

Page 27: ...Fig 4 8 Open the phone and check for liquid damages especially around the system connec tor pads X602 fig 4 6 1 2 and 4 Measure the resistance of C850 and C851 both 100 kohms both of class A and in f...

Page 28: ...ss A fig 4 3 and 4 5 If all the resistances are correct check the solderings of N800 and D600 fig 4 3 and 4 2 If the fault remains send the phone to the next level 4 8 The phone sounds strange the sou...

Page 29: ...There s nothing showing in the display or the contrast is low Insert a dummy battery into the phone start it up and check the current consump tion You could also disassemble the phone place the board...

Page 30: ...lass A Compare the results to the values at fig 5 2 Fig 5 2 All values are approximately 0 2V If any of the voltages differ from the ones in fig 5 2 measure the resistances of C633 class A 100 kohms f...

Page 31: ...correct replace C632 class A fig 5 2 and meas ure the voltages again If that doesn t help replace D600 class B If the VRPAD voltage is incorrect proceed to chapter 3 Doesn t start fault Fig 5 3 Fig 5...

Page 32: ...and the solderings are correct replace D600 class B 5 4 The display is black all the segments are lit and you can sometimes make out what it s displaying Open the phone and check for liquid damages G...

Page 33: ...one with a personal code The phone is unlocked in the reset part of the test flow If the phone displays PIN or Enter PIN it means that the SIM card is locked with a personal code Only if the phone dis...

Page 34: ...ndard Electrical Repairs 4 00021 2 FEA 209 544 11 C 34 68 Fig 6 2 Give the board power and start it up Measure the input voltage at N705 pin 2 3 1V fig 6 4 Fig 6 3 shows the component side of the boar...

Page 35: ...sistance from the marked side of R706 to the marked side of C600 0 ohms and from the unmarked side of R706 to pin 2 of N705 0 ohms If any of the resistances are too high there s a foil damage and the...

Page 36: ...easure the resistances of R600 33 ohms R627 0 ohms and R628 100 ohms allof class A and in fig 6 4 Check the resistances from the marked side of R600 to X600 pad 2 from the marked side of R627 to X600...

Page 37: ...he display 3 Press the Yes No clr and keys When pressing Yes the phone should attempt to place a call and when pressing No it should terminate it The clr key erases the symbols in the display one by o...

Page 38: ...help check the solderings at D600 pins 1 123 124 and 128 If the solderings are correct replace D600 class B fig 7 3 Fig 7 3 If the switches work as they should replace the volume keys and try again If...

Page 39: ...asure the VDIG voltage fig 7 5 3 2V If it s incorrect proceed to chapter 3 Doesn t start fault If the VDIG voltage is correct check if there s voltage 3 2V at the marked sides of R630 R634 fig 7 5 Fig...

Page 40: ...erings at D600 pin 1 120 and 122 128 If the solderings are correct replace D600 class B fig 7 3 If it doesn t help replacing D600 remove the dome switches again Check if there s VDIG 3 2V voltage at t...

Page 41: ...f there for instance is voltage at the 4 and 5 keypads but not at the 6 and volume up keypads there s a foil damage somewhere between key pads 5 and 6 and the phone is to be discarded If a column or p...

Page 42: ...at start proceed to section 8 3 If the top indicator doesn t blink green when the phone has got serv proceed to section 8 4 If the top indicator blinks green when the phone has got serv lower the bat...

Page 43: ...buzzer as in 8 1 again If the fault is repaired send the phone through the normal flow If the fault remains open the phone Give the board power and start it up Measure the voltage at H600 pad 4 3 4V...

Page 44: ...is too high it s probably R652 4 7 ohms class A fig 8 2 that s faulty If the resistor isn t faulty or incorrectly soldered there s a foil damage and the phone is to be discarded If the resistance from...

Page 45: ...ck cover If a few but not all of the LEDs aren t lit replace them If none of the LEDs are lit measure the resistance of one of them If the resistance is 0 ohms there s a short circuit in at least one...

Page 46: ...aintly glowing Open the phone and check for liquid damages Make sure all the LEDs H655 H660 all of class A fig 8 1 are mounted and cor rectly soldered Give the board power and start it up by pressing...

Page 47: ...of H600 3 4V fig 8 2 If the voltage is missing measure the VRPAD voltage 3 8V at pin 1 of V706 class A fig 8 2 If there s no voltage at pin 1 of V706 check if there s VRPAD voltage at pin 5 of N452 fi...

Page 48: ...he resistance from pin 5 of N452 to pin 1 of V706 0 ohms If the resistance is too high it s probably L450 0 ohms class A fig 8 3 that s broken If L450 isn t faulty or incorrectly soldered there s a fo...

Page 49: ...pin 5 of N452 fig 8 3 If it s incorrect or missing proceed to chapter 3 Doesn t start fault If the voltage at pin 5 of N452 is correct check the resistance from N452 pin 5 top V706 pin 1 0 ohms fig 8...

Page 50: ...ry and reinsert it after a minute If the time says 00 00 proceed to section 9 2 Compare to the correct time If the clock is speeding or if it is halted proceed to section 9 3 The component side of the...

Page 51: ...a minute Check if the fault is fixed the backup capacitor needs a few hours of charging to reach full capacity Compare to the correct time If the clock is speeding or if it is halted proceed to secti...

Page 52: ...ed Electrical Repair Note Functions that are affected if the component is replaced The specified verification should be paid extra attention when testing the telephone Trouble shooting instruction Mea...

Page 53: ...TOR Advanced C105 CAPACITOR Advanced C106 CAPACITOR Advanced C107 CAPACITOR Advanced C111 CAPACITOR Advanced C119 CAPACITOR Advanced C202 CAPACITOR Advanced C203 CAPACITOR Advanced C204 CAPACITOR Adva...

Page 54: ...CAPACITOR Advanced C351 CAPACITOR Advanced C352 CAPACITOR Advanced C353 CAPACITOR Advanced C354 CAPACITOR Advanced C355 CAPACITOR Advanced C356 CAPACITOR Advanced C357 CAPACITOR Advanced C358 CAPACITO...

Page 55: ...3 CAPACITOR Advanced C468 CAPACITOR Advanced C470 CAPACITOR Advanced C501 CAPACITOR Advanced C502 CAPACITOR Advanced C503 CAPACITOR Advanced C505 CAPACITOR Advanced C507 CAPACITOR Advanced C512 CAPACI...

Page 56: ...ITOR RJC 496 2047 1 C616 CAPACITOR RJC 464 3035 68 C626 CAPACITOR RJC 464 3035 68 Verify SIM func tion C627 CAPACITOR RJC 463 3022 1 Verify SIM func tion C628 CAPACITOR RJC 463 3022 1 Verify SIM func...

Page 57: ...erify Real Time Clock function RTC C691 CAPACITOR See Rev Change tab 1 Verify Real Time Clock function RTC C692 CAPACITOR RJC 464 3035 68 Verify Real Time Clock function Doesn t start C700 CAPACITOR R...

Page 58: ...599 2107 15 Verify handsfree earphone function Audio C814 CAPACITOR RJE 599 2107 47A Verify mic function C815 CAPACITOR RJC 463 3022 1 Verify mic function C816 CAPACITOR RJC 464 3024 1 Verify mic fun...

Page 59: ...107 11 1 Verify buzzer func tion Illumination and Buzzer H650 LIGHT EMIT TING DIODE RKZ 433 613 1 Verify red green top LED H651 LIGHT EMIT TING DIODE RKZ 433 643 1 Verify Illumination function Illumin...

Page 60: ...L424 INDUCTOR Advanced L450 FILTER REG 706 06 1 Illumination and Buzzer L501 FILTER Advanced L502 INDUCTOR Advanced L503 INDUCTOR Advanced L530 INDUCTOR Advanced N200 PROD ADAPT CIRCUIT Advanced N350...

Page 61: ...316 RESISTOR Advanced R317 RESISTOR Advanced R351 RESISTOR Advanced R352 RESISTOR Advanced R356 RESISTOR Advanced R357 RESISTOR Advanced R358 RESISTOR Advanced R400 RESISTOR Advanced R401 RESISTOR Adv...

Page 62: ...622 452 33 Verify Illumination function Illumination and Buzzer R610 RESISTOR REP 622 452 33 Verify Illumination function Illumination and Buzzer R611 RESISTOR REP 622 001 0 Verify Illumination funct...

Page 63: ...ISTOR REP 622 455 22 Verify portable handsfree function Audio R642 RESISTOR Advanced R643 RESISTOR Advanced R644 RESISTOR Advanced R645 RESISTOR Advanced R646 RESISTOR REP 622 453 33 Verify green top...

Page 64: ...SISTOR REP 622 655 15 Verify handsfree mic function Audio R807 RESISTOR REP 622 655 68 Verify display function R808 RESISTOR REP 622 656 1 Verify display function R812 RESISTOR REP 622 653 47 Verify m...

Page 65: ...ORMER Advanced V300 TRANSISTOR Advanced V301 TRANSISTOR Advanced V302 TRANSISTOR Advanced V350 TRANSISTOR Advanced V351 TRANSISTOR Advanced V420 DIODE Advanced V421 DIODE Advanced V430 TRANSISTOR Adva...

Page 66: ...on Doesn t start V705 TRANSISTOR RYN 120 647 1 Verify SIM func tion V706 TRANSISTOR RYN 121 6086 1 Verify buzzer func tion Illumination and Buzzer V708 TRANSISTOR RYN 121 6069 1 Verify On Off func tio...

Page 67: ...ard part nr 2 ROA 117 3235 2 R1A R1B R2A R2B R3A R4A R4B R4C Mounting drawing 1078 2 ROA 117 3235 2 Rev C Rev E Pos 2 ROA 117 3235 2 Part number R state C670 up to R4B not mounted R4C RJC 463 3022 1 C...

Page 68: ...PF768 Standard Electrical Repairs 4 00021 2 FEA 209 544 11 C 68 68...

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