Apple MacBook Pro A1706 CPU hot, but signs of life
Hi everyone. Got MacBook Pro 13 2016 A1706 w/ Touchbar (820-00239) with strange symptoms. It draws 20V/1A from the charger (w/o battery connected), CPU gets reasonably hot, the fans start spinning (when the CPU reaches some temp threshold), but no image, no sound, no backlight, no touchpad clicks, no keyboard backlight (also no response to CapsLock press), no image on external display (through working dongle and HDMI). The laptop chargers the battery with no issues. Also the laptop reacts to power button like it should be: it kinda "turns on" (the fans start spinning) when on battery and turns off while holding the power button as well.
The laptop was opened before, the battery was changed or at least removed from the body. Screws around display flex area was unscrewed before for unknown reason. The MB was not repaired, as far as I can tell (no flux or solder marks). No evidence of liquid damage, but one liquid indicator sticker was removed (on U7430). Visual inspection under microscope gave me nothing more.
What I've discovered so far:
- No voltage on L3500 and L8410 coils (and iGPU coils as well).
- SMC_LID_LEFT and SMC_LID_RIGHT are high.
- PP3V3_G3H is OK.
- Laptop draws 20V/1A from the charger with no battery connected (or around 20V/2A with connected battery).
- Broken J4402 connector (touchbar flex). When connected, laptop seems like bootlooping (according to USB meter) and U7600, L7600 are getting hot.
- Q7030, L7030 are getting reasonably hot (up to 50C). Don't know if it's okay.
- U4530 is getting hot when the touchpad flex is connected, and the laptop does not do any attempts to "turn on" (no heat from the CPU, no fan spinning). May be flex or TP damage.
Tried SMC reset, PRAM reset, but no luck (considering the keyboard may have no power at all). Tried to power it on without anything connected, except the USB-C port. Nothing changed.
According to my USB meter, I can assume that the laptop is booting (amps is jumping like during the normal boot process). Seems like normal boot process, the CPU gets hot, the fans are spinning at low speed, but no life.
Checked a bunch of repair cases of A1706 on the internet, but none of them has such problem. I really don't know where to move next. May be some stupid issue that I can't see though
Really hope someone can help me with the repair.
The laptop was opened before, the battery was changed or at least removed from the body. Screws around display flex area was unscrewed before for unknown reason. The MB was not repaired, as far as I can tell (no flux or solder marks). No evidence of liquid damage, but one liquid indicator sticker was removed (on U7430). Visual inspection under microscope gave me nothing more.
What I've discovered so far:
- No voltage on L3500 and L8410 coils (and iGPU coils as well).
- SMC_LID_LEFT and SMC_LID_RIGHT are high.
- PP3V3_G3H is OK.
- Laptop draws 20V/1A from the charger with no battery connected (or around 20V/2A with connected battery).
- Broken J4402 connector (touchbar flex). When connected, laptop seems like bootlooping (according to USB meter) and U7600, L7600 are getting hot.
- Q7030, L7030 are getting reasonably hot (up to 50C). Don't know if it's okay.
- U4530 is getting hot when the touchpad flex is connected, and the laptop does not do any attempts to "turn on" (no heat from the CPU, no fan spinning). May be flex or TP damage.
Tried SMC reset, PRAM reset, but no luck (considering the keyboard may have no power at all). Tried to power it on without anything connected, except the USB-C port. Nothing changed.
According to my USB meter, I can assume that the laptop is booting (amps is jumping like during the normal boot process). Seems like normal boot process, the CPU gets hot, the fans are spinning at low speed, but no life.
Checked a bunch of repair cases of A1706 on the internet, but none of them has such problem. I really don't know where to move next. May be some stupid issue that I can't see though
Really hope someone can help me with the repair.
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