A2337 - 820-02016-A - short on PP0V9_ATCRTMR1_VCCA

[samstown]

Hi,

Macbook get 5V and stay at 0.16 - 0.40 amp. I found a short on CF131 PIN1 near UF500. It's PP0V9_ATCRTMR1_VCCA. It's connected to CF143, CF130 and RF101 and RF100.

I want to make sure my diag is correct. I have .019 on diode mode, so it really looks like a short. Compare to simialr cap CF031 show .458 near UF400.

So I have three potential cap that could be sorted. I should inject 1V 2amp to find the right one ?

Thanks
Sam

 

[2informaticos]

You can claim for Nobel prize if you inject 2A with 1V into 0.019 (diode mode).

You can inject until 1.2V there, but the current will be very low; depending on the ohm resistance to ground.
No way to get anything hot.
A performant IR camera may detect some small temperature difference.

I always said: SET AMP LIMIT TO MAX ON PSU FIRST.

 

[samstown]

So the techinc is to remove one and get lucky ?

 

[2informaticos]

Remove both RF100/1 and check which side the low value remains.

 

[samstown]

RF101/2 is ok now. RF101/2 still shorted, that's PP3V3_S2SW_USBC1 and it's connected to a lot of capacitor and UF750 and UF115, UF740...

 

[2informaticos]

So the short is not on PP0V9_ATCRTMR1_VCCA; as expected.

Many components connected to PP3V3_S2SW_USBC1; including UF100.
You should test UF115 and UF740/50 first.

 

[samstown]

nothing visible on UF115 and UF740 or UF750 or around. I measure the short on each chip. So in this case what's the plan, remove one by one to check ?

 

[2informaticos]

Exactlly...

 

[samstown]

short is gone, I removed UF115, UF740 and finally UF750 (that was the culprit). I have 5 V, 04 Amp on both USB-C port, I see U0500 getting a little bit warm with thermal camera then getting cold again.

Macbook can boot without UF115, UF40 and UF750 ?

I see UF015 getting warm for a while then cold again. Same for UF500. UF400 stay warm, no pulse.

L5800 also get warm but stable.

 

[2informaticos]

You should replace them.
I have no idea about MLB behavior without them.