820-00840 20V Boost, Fluctuating PP3V3_S5

[CGid]

Have an 820-00840 Board. History of device is that it was working fine and then no longer powered on.
System boosts to 20V when plugged in, but only draws 2-10mA.
PPBUS_G3H - 13.05V
PP3V3_S5 is fluctuating from 0-3.3V in a 1-2 second cycle.
PP3V3_S5 is not shorted to ground.

Visual inspection shows no noticeably damaged or missing components.

 

[2informaticos]

Possibly another secondary power supply has problems.
Check diode mode to ground on all big coils.
Also check the outputs from page 64.