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A1534 No Power, No LED

computercaverva

computercaverva

Member
Got a mail in repair for a Retina MacBook, I assume they attempted to troubleshoot no power before sending it in for board repair. It arrived missing bottom case screws and some logic board screws. With a brand new Apple 29W charger and USB C cord it gets no signs of life and nothing seems to be getting hot.

PPBUS_G3H: 0.033V
PPVIN_G3H_P3V3G3H: 5.11V
DCIN @ F3050: 14.76V
PPBUS_S5_HS_COMPUTING_ISNS: 1.205V
PP5V_S0SW_LCD: 0V
PP5V_S0: 1-5V Drops to ~1V then spikes back up to 5V.
 
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dukefawks

Administrator
Check around ISL95530 area, sense resistors and stuff. Dead ISL95530 is also common. What is history of this board?
 
computercaverva

computercaverva

Member
Supposedly worked but needed a keyboard replacement, came in with the bottom hanging loose and pretty much a mess. I think what happened is that the computer was most likely shipped in sleep mode or with a charged battery and now has no charge in the battery and a dead board! :rolleyes:

I wouldn't have shipping a very expensive computer in this condition but I digress.
 
computercaverva

computercaverva

Member
Checking around U7000 I don't see anything that looks visually nasty, however I do have 4 Caps that are shorted to ground or the ISL is shorted. (C7000, C7001, C7006, C7002). All are on the CHGR_LDO rails.
 
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dukefawks

Administrator
This is all not making any sense.

1) PPVIN_G3H_P3V3G3H: 5.11V: C7000 is on this rail so how can you measure 5V there when it is shorted.
2) PPBUS_G3H: 0.033V and PPBUS_S5_HS_COMPUTING_ISNS are connected together yet you measure different voltages there.
3) PP5V_S0 is pulsing, this rails is powered from PPBUS so how can that be pulsing up to 5V when there is no PPBUS?

This board is already hard to fix for someone very experienced. With measurements not making sense there is 0 chance of this being fixed.

Also are you using a REAL Apple charger and USB-C cable, MUST be original APPLE!
 
computercaverva

computercaverva

Member
Finally taking this board off the shelf again to see if there is any hope for it. Disregarding all past measurements, as I cannot remember under what circumstances there were taken. The board is getting 0V at F3050 and C3101. I have tried another known working LIO USB C flex cable, and the charger is a 29W Genuine Apple brick and cord. Could it be the U3100 chip?
 
computercaverva

computercaverva

Member
Physical damage to the keyboard, Apple told the client that its a result of the physical damage, one of the usual Apple middle fingers unfortunately. F3050 is good, I will check for a short to ground and get back to you in the morning!
 
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