overshoot
Member
Hi,
I have that 820-3332 with a previous repair attempt on U8900. The rest of the board looks clean, no corrosion.
U8900 area looked pretty bad so I have decided to rebuild it swapping all the nasty components.
I did also swap U8900 from a donor board.
Once powered on, I could hear something clicking. It was Q8930.
I have now removed it, checked for short and put another in place.
Board is turning on, chime, will respond to PRAM but no GPUVcore whatsoever.
I've double checked every resistor around U8900 and they all measure fine.
I am missing the enable signal on pin38 coming from the GMux chip.
So I am now confused in where to start. Should I be getting an enable signal even if U8900 is bad or not?
It's not even pulsing.
I have that 820-3332 with a previous repair attempt on U8900. The rest of the board looks clean, no corrosion.
U8900 area looked pretty bad so I have decided to rebuild it swapping all the nasty components.
I did also swap U8900 from a donor board.
Once powered on, I could hear something clicking. It was Q8930.
I have now removed it, checked for short and put another in place.
Board is turning on, chime, will respond to PRAM but no GPUVcore whatsoever.
I've double checked every resistor around U8900 and they all measure fine.
I am missing the enable signal on pin38 coming from the GMux chip.
So I am now confused in where to start. Should I be getting an enable signal even if U8900 is bad or not?
It's not even pulsing.