820-3787-A completely dead no green light PP3V42_G3H 0V

Melvinzill

Member
Hi, have this 820-3787-A Board which is completely dead no green light. PP3V42_G3H is 0V. My DC IN Board and genuine MagSafe Charger are known good. Aynone got a idea? I habe no idea on the history, just that it had a prior repair
 

2informaticos

Administrator
Staff member
We always expect to get some voltages and signals in the first post; this helps a lot.
Check 3V42/PPBUS_G3H.

Be aware of FDMF6808 nightmare on these boards...
 

2informaticos

Administrator
Staff member
You have some time on the forum.
So we expect to post more usefull information; is your interest to gain time...

Didn't check if any short?
Some basic voltages for U7100?
 
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Melvinzill

Member
Sorry for the lack of information, I’ve just never had this exact issue and was quite frankly a bit confused about everything being 0V.... Measured all pins on U7100 and all are 0v...
 

2informaticos

Administrator
Staff member
Looks like input leakage.
We still need more tests and measurments...

Did you try fake charger, or lab power supply?
Post exact R7012 value; ohm scale, onboard.
Same for R7180/81 and R7185/86.
Check if D7010 is not open, or shorted.
Post Q7010 voltages too.
 

Melvinzill

Member
Have no fake chargers around here. In order to power with a DC Power Supply do I have to chop up a irking MagSafe 2 Charger?
 

2informaticos

Administrator
Staff member
You will need Magsafe 2 85W cable, which can power any board.

What about the other indiciouses I gave you???
 

Melvinzill

Member
Oh sorry I thought I posted those too guess I accidentally deleted the post instead of posting it or something like that... But tbh I don't think the other Voltages will be required. Upon plugging in the Charger with the DC Supply it went green and then orange before literally burning a hole in the board... The connector was already removed by another shop before...Have a look at this mess.... Is there a chance of salvaging it?
 

Melvinzill

Member
Yup it sure is. There must be some massive short here because the power supply output is dragged down to about 5v with a current draw of the maximum 5A.... Cleaning it did nothing it still smokes like crazy whenever I apply power. Also no more green light...
 
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