820-3476 pulsing

arnonabuurs

New member
Hi guys I have an 3476 with liquid damage at C7622 the line was burned. I wired it to C7624. Still there was a short on PPBUS_S5_HS_COMPUTING. I found Q7630 a bit hotter then the rest and replaced it. The short circuit is gone and instead 1.2v I get 12.56v on PPBUS. Now the board is power cycling. Vcore goes up to 1V and back to 0 and so is 5V_S0 at fan. Could this be related to the liquid? It was only a bit on one spot and the board looks quite OK in general. Any chance that the CPU can be fried as well here? Checked U1950 and ROM area looks quite clean and voltage is there 3.3v and 3.42v.

Edit: found a short in 1.05 circuit, removed U7600 but that didnt remove the short. Rest of components look pretty OK. Since its a low voltage line I figured I better not pump power through it to find the short. Any things I should be checking here?
 
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