820-01041 stuck at 5V 0.38A

[Kappy]

No liquid damage found on the board. 3 ports were going at 5v 0.42A replaced UB300 as it had a short to ground on PP3V3_UPC_TA_LDO. That is now cleared and I get 3.3v on that line.

The board is missing PP3V3_S5 and PP5V_S5_LDO (not sure if they are supposed to be present at 5v)

My main concern is PP1v8_SLPS2R as this is showing in diode mode 0.008 ( 8.3ohms) should be 0.040 but when i apply usb power i get 1.8v on PP1v8_SLPS2R

I hooked up my USB-C analyser and this gave me a fault to pin 33 on J3300 so i replaced U3000 and that's now cleared. No other faults reported with the USB-C analyser.

I've tried DFU mode - failed

So i'm not sure if PP1v8_SLPS2R is correct and why the reading is low.

All 4 ports are giving the same reading and there is no boot loop.

Any help is appreciated.

 

[2informaticos]

0.008 is too low for 1V8_SLPS2R power rail.
There is a problem for sure.
The correct voltage can be generated even with lower resistance than normal to ground.
But this denotes problems with something connected there.

 

[Kappy]

Where would you suggest the problem is.. U3000 or maybe U7000? This power line is used all over the board.

Is it going to me a matter of removing each component until it's found?

 

[2informaticos]

Inject 2V and use IR camera.
May help you to detect small temperature differences.
Remove CPU heatsink first.
You may need to wait several minutes...

 

[Kappy]

2v?? the rail is only 1.8v is that safe to do?

 

[2informaticos]

No problem to inject 10% more.
You can try 1.5-1.8V, but will not be easy to detect temperature difference.
Even 2V may not help...

 

[Kappy]

Prefect... Found the problem to be the CD3215 (U3200). Replaced and now working again.

Thank you for your help.