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820-00165, fluctuating PPDCIN_G3H

H

Hardwood T/S

Member
Hate these ones lol.

Board powers up sometimes, but most of the time when plugged in has a very dim green light and no fan spin. Looked totally clean, no signs of liquid damage.
PPDCIN_G3H fluctuates from 16.3v to about 16.7v every few seconds, and PP3v42_G3H fluctuates similarly except just above 2v. PPBUS_G3H just runs itself down from 8v, doesn't fluctuate.

Usually when I've seen this on other boards I find a missing/bad resistor somewhere along the PPDCIN_G3H line, but from the ones I tested beforehand everything looked good. It's been a while though, so I'll just recheck what you guys think should be checked first.
 
2informaticos

2informaticos

Administrator
Staff member
Post R7012 ohm value, measured onboard.
I suspect input leakage issue.

Try the board with fake charger, or PSU lab...
 
H

Hardwood T/S

Member
67.7K for R7012--but upon revisiting it's not having that problem at all, and instead shows a short on 3v42 when the board is pressed on. When the board isn't being pressed on, the fan whirs but doesn't boot fully.

I'll do the general digging for no chime, but I have no clue as to why it decided to change it's symptoms.
 
H

Hardwood T/S

Member
No history available, got it off ebay. No dents or anything on the case though, so I'm not sure about drops.

I also did some more digging and found some slight corrosion around U7600--not a ton, but enough to where it looked pretty shoddy. I took em off, tinned pads and put on a U7600 from a 3437. Unsure if those are compatible? But they seemed to have the same circuitry/ID on the chipface, so I put it on to test. Nothing changed much, although I do get a light on the charger much more consistently now.

I still have the issue where the computer will spin the fan but won't chime, or chime very infrequently. The inconsistency of the symptoms makes me think it's something to do with a bad trace, but honestly I dunno. I also don't know how U7600 would've been potentially shorting 3v42 occasionally, but I'm lost anyway lol.

Any ideas?
 
2informaticos

2informaticos

Administrator
Staff member
PPBUS_G3H still not stable?
Test the board alone, without LUO flex connectod, nor trackpad, or other device.
Just check for USB activity on MLB port.

Use R5015/16 pads, instead of power button.
Board MUST also start by itself, when charger is connected.
 
H

Hardwood T/S

Member
Unfortunately I don't have an OG magsafe 2 right now, just a magsafe 1 and an adapter! I think that'll probably mess with proper boot, so should I attempt or just order a normal magsafe 2? I should probably get one anyway lol
 
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