820-2879 not turning on PP5V_S3 shorted, no PM_SLP_S4_L

[BCN_Techs]

All S5 rails are present. No water damage. Can fin the short on PP5V_S3.


Any idea?

 

[2informaticos]

Short means what?
Post exact value to ground, ohm scale.
Do you get at least a pulse on PM_SLP_S4_L, triggering SMC_ONOFF_L?

 

[BCN_Techs]

0.5ohms to ground. Not getting pulse on PM_SLP_S4. not triggering SMC_ONOFF_L

 

[2informaticos]

Half ohm is low enough to heat something injecting voltage there.
Start with 1V and go up...

 

[BCN_Techs]

already tried. but seems nothing heat up except cables i am injecting with. Tried up to 3V, same result

 

[2informaticos]

Let ampers limit at max on lab power supply; and start with low voltage.

You are in the case where high current is required.
I already posted links for 20-40A power supplies on the forum...

 

[JohnB8812]

Something must absolutely get hot....inspect caps by Audio IC common short on 13" unibodies

 

[BCN_Techs]

checked, injecting 2.43Amps with 4V through C4690 pin 1 and absolutely nothing is getting not warm. checked everything.

 

[BCN_Techs]

C6213 was the problem. Thank you. U were right it was getting very hot.

 

[JohnB8812]

Nicely done