A1286 fans go on and off

[macsoluter]

This MacBook pro had an issue with the gpu ? After warming up the gpu with a flow heater, the fans go on and off
An current sence issue ? But where to look for the problem ? I warm it up to hot ? and how can I know that the gpu is blowup?

 

[chscag]

What exactly are you trying to do? It sounds like you're trying to reflow the GPU on your MacBook Pro? If so, that's always a risk you take in that it can damage other components if you're not careful. And the procedure doesn't always work.

 

[macsoluter]

I measure a lot of points . PP5V_S3 goes on/off : 5V->0V->5V-0V.... I measured this powerline in diode mode for looking a short circuit and this give 0,422 , so not shorted ?
[doublepost=1566115778][/doublepost]I think it is a current sense problem ?

 

[macsoluter]

See my measure points :
PP5V_S3 0-5-0-5-0V 5V ON/OFF
short check = 0,422 = good board
PP5V_S0 0-5-0-5-0V 5V ON/OFF schommelt tussen 5V en 0,18V
short check = 0,395 = good board

 

[macsoluter]

See my measure points :
PP5V_S3 0-5-0-5-0V 5V ON/OFF
short check = 0,422 = good board
PP5V_S0 0-5-0-5-0V 5V ON/OFF
short check = 0,395 = good board

It's a MacBook Pro A1286 from 2011
can somebody help me how to find the current issue ?

 

[macsoluter]

Here are some measures :
PPVCORE_GPU : 0volt
PM_SLP_S4_L : on/off 0,300volt and 1,5volt
Fans start and stop after 1s and continuous

 

[macsoluter]

There's a short circuit on PPVCORE_S0.
See attached in red, which components I have removed and I still have a short circuit on PPVCORE_S0.
So the short is in the line from R8940 (see appendix 2).
or in the GPU chip or in one of the capacitors (see appendix 3).
The question now is how can I find the capacitor that could be broken ? A separate power supply of 0.9V on PPVCORE_S0 with an adjustable current ? Is this a good idea ? and then measure the temperature of each capacitor ? Does anyone have experience with this ? What equipment do you use for this ? I can't solder every capacitor, can I?