Macbook 820-01814 PPBUS Shorted.

Instafixx

Member
PPBUS is shorted.
Inject 1V - Very low AMP draw.
Went upto 5V and the only thing that caught my thermal camera was U9080.

L9081 (PP2V5_NAND_SSD0 and P2V5_SW2_TPS62180_SSD0) Diode mode Readings are 0.167 which is low as per openboarddata.

Removed L9081. PP2V5_NAND_SSd0 is partially shorted - Diode Reading 0.167. PPBUS is no longer shorted.
Removed L9080 - still same.

Removed U9080.
PP2V5_NAND_SSD0 drops down to 0.117
 
Last edited:

2informaticos

Administrator
Staff member
Bad NAND chips.
You forced them with 5V, but damage came from initial overvoltage through U9080.

BTW, never inject such high voltage, before proper checking of secondary power rails.
 

Instafixx

Member
I had checked all the big coils.
Didnt check the ssd coils. My Bad.

Any link for how to go about replacing NAND chips.
It is my own laptop so will fix it at leisure
 

2informaticos

Administrator
Staff member
You should get the chips from same model donor board (same SSD size), maintaining the same postion on the board.
Can use new chips, or from different board if you can initialize them properly, according with the board position.
You can do that with dedicated programmer, like JCID P13.
 

Instafixx

Member
I understood. Can we re-use the non shorted chips and a new one from another board and program them via JC programmer in the correct order ?
 

Instafixx

Member
Hi,
So i wanted to order the Chips for the NAND.
All i can see is that 512gb Version has 2 x TSB4227 and 2x TSB4228 NANDs.

But my board has Sandisk NANDs. (Black Version).

Can you help me out?
 

Instafixx

Member
I replaced all 4 NANDs as per the JC Programmer and put them at the correct places.

All 4 are 00 of 0/1/2/4th Order.

Power Rails are stable for more than 30 seconds.
Pp2v5
Ppbus (12.3V)

Machine detects in recovery mode.
I did a bare board restore and got error 1.

Connected the trackpad and everything else.

Now i get USB Host Error 9.

Where could i have gone wrong ??
 
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