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820-3332-A MacBook Pro Retina 15" A1398 No display 3 Beeps

I

ielectron

Member
Hi everyone,
I have this MacBook Pro for repair board 820-3332-A
Got it with 3 beeps issue have tired reflow ram replace PCH no luck I decide to replace CPU because it was getting crazy warm.
After replacement (I remove same CPU from Donner board) with was liquid damage but I was getting a display but it was too badly corroded to fix and many things doesn't work properly.
After CPU swap laptop is turning on with no beeps but there is no display no chime fan is spinning I measure board and no power on a main rails..
There was no liquid damage on board with 3 beeps.
I have thinking maybe CPU is not connected properly but I bit worried with next soldering attempt it will die as to many times heated up.
I tried also turn on laptop on SMC bypass and all missing rails have a right voltage only PPVCORE_S0_AXG2_L & PPVCORE_S0_AXG1_L are not present.
Any ideas ? Is any chance that something else could cause this issue.
PP1V05_S0 1.05V ok

PP1V5_S0 1.52V ok

PP1V8_S0 1.81V ok

PP3V3_S0 3.34V ok

PPVCORE_GPU missing

PPVCORE_S0_CPU missing

PPVCORE_S0_AXG missing

PP1V5_S3RS0_CPUDDR 1.34V ok
PP1V5R1V35_S0GPU missing
PP3V3_S0GPU missing
PP1V0_S0GPU_ISNS missing
PPCPUVCCIO_S0_REG_R 1.01V
VCCSAS0_LL 0,94V
GPUFB_LL 0V missing
PPVCORE_S0_CPU_PH1 missing
PPVCORE_S0_CPU_PH2 missing
PPVCORE_S0_CPU_PH3 missing
PPVCORE_S0_AXG2_L missing
PPVCORE_S0_AXG1_L missing
 
2informaticos

2informaticos

Administrator
Staff member
"PPVCORE_GPU missing"
Did you reflow U8900?
Post its volatges, if still nothing after reflow; yoy may need to change it.

"PPVCORE_S0_AXG2_L & PPVCORE_S0_AXG1_L"
This voltage only appears when you open youtube, or other high graphics load on iGPU...
 
I

ielectron

Member
Thanks for response.

I do tried reflow and replace U8900 prior CPU replacement, voltages bellow. I didn't reflow or replace it after CPU replacement.

JohnB8812 those CPU are that sensitive for temperature? Sorry for silly questions but never replace those Intel CPU's before so don't have too much experience with it. I have replace twice on A1502 and there was no issues, also many GPU & PCH previously.

Voltages from U8900
  1. 0.98v go down to 0v
  2. 0v
  3. 0.05v
  4. 0v
  5. 0v
  6. 0v
  7. 0v
  8. 0v
  9. 0v
  10. 0v
  11. 0v
  12. 0v
  13. 0v
  14. 0v
  15. 0v
  16. 5.03v
  17. 12.01v
  18. 0v
  19. 4.7v
  20. 0v
  21. 0v
  22. 0v
  23. 0v
  24. Nc
  25. 5.03v
  26. 0v
  27. 0v
  28. 0v
  29. 0v
  30. 4.69v
  31. 0v
  32. 0v
  33. 0v
  34. 0v
  35. 0v
  36. 0v
  37. 0v
  38. 0v
  39. 0v
  40. Gnd
 
2informaticos

2informaticos

Administrator
Staff member
Is probably waste of time.
You can check at least diode mode readings on all PCI-E caps (C80xx) from page 71.
The caps are divided in pairs and you should get same value on any pair.
And normally two different values between pairs.
 
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