[solved] 820-2936 fan spins for one second then stops then starts then stops {CLOCK ISSUE}

[XooP]

[solved] 820-2936 fan spins for one second then stops then starts then stops {CLOCK ISSUE}

Got this liquid damaged 820-2936 board. There where corrosion on both sides of the board around U3890.
R3888 was blown and I have replaced it. I have also replaced all the large caps above U3890 since they looked really bad.
The board shows the same symptoms before and after.

Any idea that can help me a bit further with this one?

 

[larossmann]

U2800 is probably fucked, check it. Also check resistance between pins 17/18 of U7000, but 99% it's fucked U2800.

 

[XooP]

Did some measuring and I also have 0v on the output of Q3880, shouldn't there be 12,56v here?

 

[dukefawks]

Q3880 is in T29 circuit and is for the thunderbolt port, has nothing to do with the board working. Measure the voltage on Y2805, if over 1.6V then U2800 is dead.

 

[XooP]

Louis was totally right, replaced U2800 and the fan spins, that means that the computer is totally fine doesn't it?

 

[XooP]

And off course, so are you Dukefawks

Thank you both so much, another success...