So I've tried to narrow this down but can't seem to find the issue. Have a NBAFB that works perfect but no flashers. Also no 20v.
Keeps blowing fuse F107 flasher secondary. 4a250v SB. Removed the power connector @ J128 and its fine, doesn't blow fuse. Connect J128 and disconnect flash/sol power @ J133/134 Still blows. So not a short issue. But replaced capacitor C10 with new one. Still blows fuse. Traced line back to interlock harness. Removed harness (bypassed) and connected directly to transformer harness. Still blows fuse. Power tested at 20v test point is 10.2 with blown fuse. Any ideas?

The WPC-95 Power/Driver : The bridge rectifiers are replaced by ganged 6A2 diodes and the filter capacitors were spec'd down from 15,000µF to 10,000µF.

D15 had no volts. The rest had 7-9. Thanks for the tip!