820-01041 Touchbar MPB Short on PP2V5_NAND_SSD0

[goldminer76]

I have a short on PP2V5_NAND_SSD0

History: Saw only tiniest bit of liquid on U9080 which caused a short on PPBUS_G3H_SSD0_SNS

Replaced U9080 Short gone

Still short on PP2V5_NAND_SSD0

Removed U9000 and still have a short on PP2V5_NAND_SSD0

I see plenty of caps to look at and of course the NAND so I'm just asking for a little help in figuring out if this is a shorted cap or what without having to remove all the caps one by one. I also am afraid to inject any power because NAND

 

[2informaticos]

Which is the exact ohm value of this short?
No danger, if you do not inject more than 2.8V aprox.
If the short is less than 1 ohm, you may have the luck to detect something heating.

 

[goldminer76]

ohm value 0.9

I looked with infra red camera but only saw U9000 heating up so thats why I took it off but there is still a short.
2.8v and how many amps should I use?

Thank you for the help!

 

[2informaticos]

You don't need to reach 2.8V for such low value.

Very strange your question.
According to Ohm law you cannot adjust voltage and current at same time, if resistance is stable!
In other words, for given resistance and voltage, you cannot vary the current.
Just start with 1V and increase slowly.
You may need a PSU with more than 5A limit supposedly.
If 0.9 ohm short resistance includes multimeter leads resistance, real short is less than 0.5 ohm.
The PSU may need to inject high current at low voltage.
2V on 0.5 ohm means 4A and 8W, which should heat something.
I suppose PSU leads have much lower resistance that your multimeter.

 

[goldminer76]

I used 6A and 1v and the only thing that heats up is U8700 (NAND) Am I screwed?

 

[2informaticos]

1V with 6A means 0.16 ohm for short value.
If you mean just set current limit at 6A, is not what you think!
Don't get confuse between injected current and a limit which you set on PSU.
ALWAYS let current limit at max, for voltage injection; the actual injected current is dictated by applied voltage and short resistance.

However, if U8700 heats with just 1V, is the culprit.

 

[goldminer76]

Oh wow. I need to read up and study more on voltage. Thank you so much again for your experience and expertise. Looks like NAND is shorted. BUmmer

 

[No-Clean]

I have the same issue, in my case I had to replace U9080 and 3 NAND chips to get rid of the short, after that the problem I have now is that I cannot restore the T2 firmware, I keep getting error 9 when I restore. I will create its own post to see if we can solve it.

 

[iClub]

I am having the same problem, has anyone got a solution?