Certainly is a hope... is alreaby woking before
The color vanished only after changing flyback, or when you changed components or resolder?
If only was after flyback change, maybe the pulses derived from flyback have different amplitude, upsetting circuits depentent form it, if flyback is a equivalent?
And, a very small invisible solder splotch/blob can maybe ocurred at some position (washing the PCB with isopropyl alcohol using a hard brush may solve it).