820-02100 SSD REPLACEMENT

huzeafa

Member
Hello guys.
Please I need help with a 16-inch 820-02100 board. The Board was working but would restart immediately after the OS started to load, it is the same thing when I try to press and hold down the power button to access recovery, I tried to restore the device in DFU MODE on multiple attempts, and I got error code suggesting a possible issue with the NAND, I then decided to replace the NANDS, this is not the first time I have replaced NANDS on this boards, I usually do a direct transfer from a similar board with similar NAND arrangements, for example, the board am currently working on, only has one side of the wing populated, hence I used a similar board. After installations, I am not able to restore the device, won't even go into DFU Mode, the MAG safe 3 cable connected keeps going on and off, as the device is circling, I thought might be the NAND, so I took a different set from a similar board, but the behavior remains the same.
 

huzeafa

Member
Check diode mode on all secondary power supplies.
Do you get stable PPBUS_AON and 3V8_AON now?
I have a stable 3V8_AON. However, PPBUS goes high to 12.0V and then drops to 6V or so and quickly goes high to 12.0V. At the same time, I noticed PPDCIN goes up to 20V and then quickly circles down to 5V, which corresponds to when PPBUS circles down to about 6V.

I compared diode mode measurements on a working board and got about the same reading.

PLS NOTE: The above behavior is what I get without SSD on the board.

So am not sure how to tackle this.
 

huzeafa

Member
is there something else I should do regarding the NAND REPLACEMENT? Should I get a different set of NANDS ?
 

2informaticos

Administrator
Staff member
If you got the NANDs from same model board and respect basic rules, it should work.
If not, bad solders, bad chips, something else affected on the board by heat...
 
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