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820-3332 PPBUS_G3H shorted

ytesfay80

ytesfay80

Member
The customer said this stopped working one day and they took it to a shop so I'm not sure if they cleaned it. I don't see any corrosion anywhere but I do see some discolored probe points.
I measured F7041 in diode mode and PPBUS_G3H was measuring 0v to ground. I removed L7030 and found that Pin 2 was the side that was shorted.

I hooked my power supply to inject voltage onto Pin 2 and when I get to around 0.5v it starts pulling the maximum 5 amps. I checked all the ppbus_g3h areas on the boardview but I don't feel anything getting very hot.

Is there any common areas I should look for or do I just need to check more carefully?
 
PhilipC

PhilipC

New member
You would definetly feel 5amps, leave it plugged in for a while and see which areas are hot that way you can pinpoint the component easier
 
A

aprendiz

Moderator
Measure on diode mode from L7030 pin 2 to all big coils, if any of those measures give you continuity, there is the problem, the most common is L7520-L7530..
 
ytesfay80

ytesfay80

Member
Okay I measured in diode mode and all the coils in that area are measuring 0v to ground.
L7510/20/30/50/60, L8930/60, L7100 and even L9830.

I injected the voltage again and waited a while but I still don't feel anything getting warm.
 
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ytesfay80

ytesfay80

Member
Yes I did that. I had one probe on Pin 2 of L7030 and I put the other probe on all the coils I mentioned previously.
 
ytesfay80

ytesfay80

Member
In diode mode with one probe on Pin 2 of L7030 and the other probe on all of below coils measured 0v to ground.
L7510/20/30/50/60, L8930/60, L7100 and even L9830.
 
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ytesfay80

ytesfay80

Member
I still don't feel anything even getting remotely warm. I removed the heatsink and the cpu/gpu doesn't get warm at all. I even let it inject voltage for 5 minutes to see if anything got warm but nothing.

If the short was inside the board wouldn't something get slightly warm?
 
D

dukefawks

Administrator
I have no idea man. If there really is 5A going into the board it must get at least warm somewhere. Use freeze spray or your lips to feel the board.
 
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