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820-2567 /// PP3V42_G3H short to ground /// dim green light

Nick

Nick

New member
Hello everyone, new to the buisness so bear with me on some stuff, i have been fixing only "normal" laptops, i am new to apple shit

i got a 820-2567 board which PP3V42_G3H_REG is shorted to ground (4ohm)

someone have put his hands on this thing before because l6995 is missing and JUMPED. needless to say u6990 is burned.

replaced it leaving open l6995 gives me a dim green light (sometimes flickering orange) PP3V42_G3H_REG after l6995 with the coil removed is shorted to ground. i have spent 2 hours removing shit here and there but i am out of patience right now so i am asking you gurus some guidance... i am tempted to replace the ISL

thank you guys
 
Nick

Nick

New member
i tried injecting 3volts after l6995 on the PP3V42_G3H line but no components gets hot, i don't have a Flir so i tried the "alcohol tecnique" of Luis but still no results. i am in a blind spot
 
Nick

Nick

New member
I have tried with my lips but I feel a bit of warmth only towards the magsafe connector part, I don't have the schematics with me now but I am pretty sure it is the AND logic ic, it should be u6901 but I doubt it is shorted. I already tested each and every cap in that zone and they seems alright

my power bench psu is busted so until the new one arrives I am sticking using a repurposed desktop pc psu. The current draw is high enough to bust a diode I have put at the 3v output of it after a minute. It gets boiling hot
 
2informaticos

2informaticos

Administrator
Staff member
Injecting 3V into 4ohms means less than 1A, so let it time...
Remove heatsink and pay atention to MCP if heats a bit.
MCP easy disipates heat on the board, so dificil to detect if it is the culprit...
 
Nick

Nick

New member
I didn't feel warmth from the MCP but I didn't really care for it the first time (heatsink already removed) tomorrow when I am back into the office I will check it. Customer said that the product stopped working after he accidentally dropped it. I didn't see signs of water damage but the idiot that handled it earlier probably cleaned it I don't know.
if it is the mcp what am I looking to do? Reballing it?
 
larossmann

larossmann

Administrator
Staff member
Reballing will not fix a bad MCP. Make sure heatsink is off and feel around again, something should get warm at 4 ohms.
 
Nick

Nick

New member
Those boards around here are still 150/200€

found the problem guys, u6901 was busted. I found it out increasing the voltage a bit and letting it go for more time. Removed the ic and the short was no more. I don't have a donor board, so I ordered the ic from mouser. Can't wait to see if I get a green light. Thank you guys for your input!
 
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