820-3115 not turning on, PPVRTC_G3H and PP3V3_S5 jumping around

JohnB8812

New member
Oh yeah I should prob add that this is a replacement board has a sharpie mark on top of each coil, port, and anything silver.
 

JohnB8812

New member
Actually no on pin 6 of U7200 it's a constant 0.772 volts which I'm guessing is definitely lower than it should be. It's the same on R7272 and Q7221. PP3V3S5_EN_L is not present.
 

JohnB8812

New member
Update: Found some liquid damage it was very hard to see but it was C4617, L4600, and U3311 but none of those have to do with this I would guess?
 

JohnB8812

New member
Starting to think there's a blown trace or internal short. Idk what the deal might be also noticed on the back of the board for Firewire and the other ports there were components loose and corroded. I wonder if someone messed with this board before or if it was assembled by someone who was careless.
 

JohnB8812

New member
Ok now I have created a bigger problem :/ I tried a new TPS51125 just to be safe, and when I did, somehow the PPBUS_S5_HS pin quite literally burned the trace. I ran a jumper from C7272 to the pad and then properly soldered the U7200 back on and checked each pad. However, now I still have a green light, but PPBUS_G3H is only .23 volts. It is not shorted to ground, but now I have another problem because I made a stupid mistake. Where would I go from here?
 

JohnB8812

New member
Well looks like maybe a short now wasn't yesterday. Looks like resistance is 0.4 ohms At best but it does drop to zero.
 
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