820-2879 PPDCIN and PPBUS G3H rise and fall


Board never starts.

Removed F7040 and both PPBUS and PPDCIN rise and drop. At first I thought was related to TPS chip being PPBUS is sometimes 12.65V and drops but if the DCIN is rolling from 16V and dropping, different issue I'm guessing?

No shorts on any of the coils and made sure to check L7220/60.

SHould I be focusing on U7200 for the issues or would that not also cause PPDCIN to rise and fall also?


Staff member
Test with fake charger, or lab PSU and 60W cable.
Possibly input leakage issue; many times caused by Q7080/85.