820-2850 no image, pendrive doesn't flash, no brain despite vcore present

djdblaster

New member
No history except that I see some caps for PPVCORE_S0_CPU were touched with solder. Maybe even replaced. Owner said it doesn't produce any image on screen.

Laptop starts, fans spin, I "think" (went quickly through voltage rail check), that voltages are present. Tried with external monitor, no luck.

Any point what to check next? Thanks
 

JohnB8812

New member
Try a new BIOS. Keep old one in case that is the issue. If no change, probably going to be a sucky one possibly no fix
 

djdblaster

New member
L7630 --------------------- 1.08v
L7720 --------------------- 1.8v
L7760 --------------------- 1.2v
ALL_SYS_PWRGD --- 3.3v
 

2informaticos

Administrator
Staff member
Did you try one RAM module at a time, different DDR3 speed?
If someone changed caps on CPU area using hot air, overheating CPU, this board could be trash now.
 

djdblaster

New member
No Title

Without RAM, there are no beeps (speaker is connected)

With faster RAM and one slot at a time, no luck.

*These caps were worked on (see pic)

**Tiny cap bottom left is fine, but I have aligned it after.
 

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djdblaster

New member
Got it. It's in 0 state.

Alright, so any more ideas what could be wrong with the board? Are there any data lines that could be stopping Macbook from booting, just like with an iPhone?
 

djdblaster

New member
PPVCORE_S0_CPU measures around 40 Ohms. Nothing gets too hot. I know there's tons of balls under CPU and PCH, but is there a way to check something that could point in some way/tell something about CPU?
 
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