Removed solder and
re-soldered all components from triangle generator, checked all diodes for
normal behavior (in circuit).
Did you already check CR245/CR248/CR250/CR246 and resistors R245, R248, R250? The voltages you measured at two sides of the bridge are not consistent if all the components are good. Perhaps component tester failed to catch the intermittent behavior. Do you measure 1.116-0.6=0.516V at cathode of CR248 in stuck state? Or do you measure a negative voltage (bad CR248)?
Ozan
