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    820-00138 I/O board USB problem

    C9501/02 are not shorted. Pin 2 on both caps reads OL, pin 1 reads 0,335V in diode mode. Traces are OK too. data lines diode mode readings (I/O board disconnected): USB3_EXTB_R2D_N - OL USB3_EXTB_R2D_P - OL USB3_EXTB_R2R_N - 0,323 USB3_EXTB_R2R_P - 0,323 USB_EXTB_N - 0,367 USB_EXTB_P - 0,369...
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    820-00138 I/O board USB problem

    On the similar machine right port works normally, it detects and charges iPhone (or other phones). USB_EXTB_OC_L line is stable 3,3V and doesn't change if I connect USB device.
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    820-00138 I/O board USB problem

    It raises to 3,3V when computer turns on and stays like that all the time, no matter if I connect devices to USB port.
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    820-00138 I/O board USB problem

    This one is really strange. I got A1398 which is working perfectly fine except right side USB port, which is working partially - it recognises external flash drives, USB mouses or even boots and works from external drive OS, but the problem is, that it doesn't recognise iPhone at all. AMP meter...
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    820-00165 pulsing twice

    @2informaticos, I have heated CPU with flux and later put board in USC, sadly it hasn't changed anything...
  6. N

    820-00165 pulsing twice

    Yes, PLT_RESET_L pulses twice to 3,3v then drops to 0v and stays like that.
  7. N

    820-00165 pulsing twice

    I'm working on 820-00165 board, which came to me completely dead. After inspection I found out: - small corrosion between C7400 /C7425 and C2951/C2952 - PP3V3_S4 was completely shorted to ground, but it was caused by damaged U8000 (no corrosion around). I've replaced caps and U8000. Now...
  8. N

    820-00165 no PP5V_S4RS3 and PP3V3_SUS

    Yes, I know that. Just thought, that my multimeter is too slow to catch short pulse on this line and bad bios cause PCH to cut it off.
  9. N

    820-00165 no PP5V_S4RS3 and PP3V3_SUS

    For me it sounds a bit strange, that it could kill PCH.. Is it worth to try changing bios? Or in this state it's pointless?
  10. N

    820-00165 no PP5V_S4RS3 and PP3V3_SUS

    These are reading for lines you mentioned: PM_DSW_PWRGD is 3,42V PCH_DSWVRMEN is 3,22V SMC_ADAPTER_EN is 3,42V PM_BATLOW_L is 3,22V RTC signals: PCH_CLK32K_RTCX is 0,441V PCH_INTRUDER_L is 2,35V PCH_INTVRMEN is 3,22V PCH_SRTCRST_L is 3,3V RTC_RESET_L is 3,3V
  11. N

    820-00165 no PP5V_S4RS3 and PP3V3_SUS

    I'm working on 820-00165 board, which came to me with description: "Turned off by itself, after a while turned on, but SSD wasn't detected. Now has no reaction for charger". My observations: - board is clean, no corrosion, no water damage, no mechanical damage. - there is no green light when...
  12. N

    820-00850 5v no power, PPBUS_G3H shorted, no PP3v3_G3H

    I'm sure about these readings. I have injected safe 2V 2 Amps and foud out, that C6455 on PPBUS_G3H_SPKRAMP_LEFT line is glowing on thermal cam like crazy. After removing it PPBUS_G3H and PPBUS_HS_CPU are measuring 0,384V in diode mode, so I think case is solved.
  13. N

    820-00850 5v no power, PPBUS_G3H shorted, no PP3v3_G3H

    Other coils are not shorted. Caps on PPBUS_G3H and PPBUS_HS_CPU looks fine, no damages. The only way to find damaged one is to inject voltage and use thermal cam. Is it safe for CPU now to inject voltage to PPBUS_G3H with all CPU coils removed? Or I should separate PPBUS_G3H and PPBUS_HS_CPU...
  14. N

    820-00850 5v no power, PPBUS_G3H shorted, no PP3v3_G3H

    I have removed all CPU coils and short on PPBUS_G3H is not gone. These are readings on CPU rails (CPU side): PPV095_S0_CPUVCCIO_REG_R - 43,0 ohm PPVCCSA_CPU_R - 9,9 ohm PPVCC_CPU_PH1- 2,9 ohm PPVCC_CPU_PH2 - 2,9 ohm PPVCCGT_CPU_PH1 - 2,5 ohm PPVCCGT_CPU_PH2 - 2,5 ohm PPVCCGT_CPU_PH3 - 2,5 ohm...
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    820-00850 5v no power, PPBUS_G3H shorted, no PP3v3_G3H

    I'm working on 820-00850 board, it has no signs of liquid or physical damage. Customer states computer just turned off by itself. Some info about board: - Stuck at 5v 0,45A - LDO's on CD3215 are not shorted - PPBUS_G3H is 0V, shorted to groud on system side (diode mode 0,000V) - PPBUS_HS_CPU...
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    820-00840 brain dead

    I have inspected LCD flex cable and connector both on motherboard and LCD sides and there are no signs of liquid. I can't see any data lines on corroded are going straight to CPU. Even though it's possible, that CPU died?
  17. N

    820-00840 brain dead

    I'm working on 820-00840 board which got damaged by coffee spill. It had corrossion around U3700/U3770/U2890/U3900/R5640/U8210 (pictures attached). I have cleaned it up, replaced U3770 and U2890, repaired broken traces, replaced damaged resistors/caps. Also resoldered U3700 and U8210. Area of...
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    820-00597-A iMac 21,5" 2017 random restarts, problem with booting to OS

    I have - the same thing. I have inspected board for damaged components but it looks perfect..
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    820-00597-A iMac 21,5" 2017 random restarts, problem with booting to OS

    I haven't tried BIOS files sent by you because after few days of waiting in the queue iMac doesn't turn on at all. It was untouched, I have turned it off last time, took out power cable and disconneced screen.. today it only has one diode light up on and doesnt react to power button, even if I...
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