A1990 820-01814 - 5V on charger 0.4A - Short on U9080

[it-solve]

Hi Guys,

Got this 15 Macbook which had liquid damage. Quite extensive around the U9080, U4900

After cleaning the area I have discovered that I get dead short 0.66Ohm on L9081 P2V5_SW2_TPS62180_SSD0
The other output of U9080 - L9080 P2V5_SW1_TPS62180_SSD0 is reporting 2.08 MOhm - 0.44 Diode. These measures are with removed L9080/1 coils

P2V5_NAND_SSD0 is 1.30 Ohm

U9080 is heating up, which perhaps is explained by the short.

I lifted up R5600, thinking it may be the only G3H feeding the U9080.
When lifted up, U9000 heats up (up to 60*C) together with U8800/8700

Then, I lifted up R5620 too and managed to get 20V 0.4A on the charger.

is this dead TPS62180? Or is there a possibility U9000 to be busted too? Which doesn't seem to be available anywhere?

Regards



Seems like need to order it and wait 2 weeks, and was wondering if there anything else I can check before I fix this short?

 

[2informaticos]

Which schematic are you using?

 

[it-solve]

Could not find this board schematic, but A1990 820-01041 is close enough.

 

[2informaticos]

You should change U9080 first.

But I'm not sure what you mean with:
"L9080 P2V5_SW1_TPS62180_SSD0 is reporting 2.08 MOhm - 0.44 Diode
------------------------
P2V5_SW1_TPS62180_SSD0 is 1.30 Ohm"

 

[it-solve]

These long names are very confusing. Corrected it, I meant P2V5_NAND_SSD0 is 1.30 Ohm.
Thinking of the NANDs internal resistance. It is expected to be that low right?

I will order u9080 then and will report once replaced.

Thank you again.

 

[2informaticos]

Impossible to have 1.3 ohm at NAND power rail.
Apart of U9080, something else is burnt there; NAND chip I think.
May be not worth to continue repairing this board...

 

[it-solve]

Just received the U9080 and replaced it.

It fires up to 20V/0.9A for a couple of minutes, then drops to 20V/0.5A. But U8800 is heating up to over 100*C.

P2V5_SW1_TPS62180_SSD0 - 0.93Ohm
P2V5_SW2_TPS62180_SSD0 - 0.95Ohm

It seems like you were right, must be a shorted NAND. I assume we cannot disable a NAND?

 

[2informaticos]

You cannot disable any NAND.
If you have time to waste, try replacing shorted NAND with a chip from donor board, same model.
It has specific information, cannot be replaced with new.