820-2936 No red light

[arnonabuurs]

Hi fellows, I have a mac pro 2936 which has both PPBus G3H as well as 3.42 line but no red light. Any tip for troubleshooting? Can we still have power in de PP3V42_G3H and maybe the one wire adapter sense is not good, or would there be no power on 3.42 if some part of the circuit is damaged? Sorry for the noob question

Edit i also noticed R5400 is missing but that wont be powered anyway without the system starting,i gues

 

[aprendiz]

Green light is ok then???? R5400 has nothing to do with green/orange light but it should be present ......

 

[arnonabuurs]

No there is no light at all but i do measure G3H and 3.42V

 

[dukefawks]

PPBUS_G3H at 12.3V or 12.56V?

 

[arnonabuurs]

hi duke, 12.62v at F7040

 

[dukefawks]

That means SMC is running.
1) Did you try a known good magsafe board?
2) U6901 pin 1 and 2 got 3V?
3) R5710 got 3V?

 

[arnonabuurs]

1) yes
2) yes we have put pin 5 is burned incl trace, I guess thats a problem, no 3.42v here
3) yes

 

[dukefawks]

I assume you fixed this by replacing U6901 and fixing the trace?

 

[arnonabuurs]

Hey Duke, its still on the pile will try it over the weekend. I have another troublesome board at hands will post a new topic for that.

 

[larossmann]

Do this one first since it's the easy fix!

 

[arnonabuurs]

You havent seen the board yet, its a pile of crap it was "fixed" before and previous shop borrowed some chips, also liquid damaged many chips have a nice shitty color. Might give it a try over the weekend, it is a challenge