820-00850 Fan spinning up

bjf

Member
This board is fully functional but the fans spin up after a few seconds. I've tried it in an entirely different case and it does the same thing. I replaced Q5871 being that it was one of the few areas to be hit. No change. Online test shows no issues. I've attached pictures taken before cleaning. The only other area that seemed to get hit was the backlight circuit and that's all good. Not sure where to go next.


IMG_5565.JPGIMG_5566_0.JPG
 

bjf

Member
No change after disconnecting webcam.

I've tried this board in a known-good case and it does the same thing.

Heatpipe Outgoing Air is at 128C. I'm trying now to figure out where that sensor is.
 
Last edited:

bjf

Member
U5860 was where there was some light sign of the spill. I replaced U5860 and the 3 components above it. The fan still spins up but Heatpipe Outgoing Air is now down to a normal 30C. Everything seems very clean and solid around U5860, and in general. Nothing burnt. No blown pads or traces. The spill was very minimal. I'm stumped why the fan is still spinning up.
 

bjf

Member
The sensors are all inside of big chips? Is that correct? So my goal is to just look for blown traces/connections?
 

bjf

Member
Not sure what to do with this besides give up. I replaced Q5871 because it got hit. I replaced U5870 also just in case. Q5872, Q5873, Q5874 are all good. Lines and measurements are all good compared to a good board.
 

bjf

Member
Yes, traces are all good. Continuity is there. I replaced Q5871 again just in case. No change. Removed C5871. Fan still spins up the same way. Nothing changed.
 

bjf

Member
Ok, I haven't fully tested it for performance, but I'll try it. I'm going to put that capacitor back on and give it a try with fan control.
 
Top