(347) 552-2258 [email protected]

820-01958-A Two Nand chips getting hot

prodigy83

prodigy83

Member
Have a 820-01958-A with liquid damage/corrosion. I have cleaned up the board, and I found a short on the C9072 pin 1 which does correspond with the two nand chips U8700 and U8600. Thermal camera shows U8700 is getting the hottest, but both are getting pretty hot. I have removed C9072, C9071 (one side was singed), and R9067. Is there anything else that could cause these NAND chips to heat up like this? These two chips appeared to be sealed in the board. Thank you in advance.
 
prodigy83

prodigy83

Member
Also L9060 pin 2 reads 4.2-4.3v, stays at this for about 6 or so seconds, and then drops to 0, then jumps back up again to the same 4.2-4.3v, while plugged in to the USB charger.
 
2informaticos

2informaticos

Administrator
Staff member
U9060 got damaged by liquid and NAND was fried.
You should remove U9060 and check resistance to ground at L9060.
Voltage injection method may help to find the dead NAND chip; maybe only U8700.
 
prodigy83

prodigy83

Member
Removed L9060 and pin 2 reads 22mv, but drops to 0, then repeats. Pin 1 reads 12.17, then drops to 1.1v. I have not removed U9060 yet. Going to do that next. If the Nand is fried, are these even replaceable?
 
2informaticos

2informaticos

Administrator
Staff member
I asked about resistance (ohm scale), not voltage.
I can't understand why are you still applying power on the board...
 
2informaticos

2informaticos

Administrator
Staff member
"Voltage injection method may help to find the dead NAND chip; maybe only U8700."
Once removed one chip, check resistance to ground again; let the board to cool down first.
 
prodigy83

prodigy83

Member
U8700 Nand has been removed. L9060 is reading 4.4 ohms. Not sure what to do next? I did inject voltage at R8708 pin 1 and then tested to see if any voltage is coming through, and I got nothing coming through. I assume test another EXT point to see if the other Nand chip is fried too?
 
You must log in or register to reply here.
Top