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I am trying to repair my stove Vacuum Fluorescent Display circuit board. One or two segments light up and quickly fade away. The circuit board model is ORBITRON A-403 from Borg Instruments INC. Diehl timer control division. I cannot find a circuit diagram. By reverse engineering I found that xfmer secondary winding negative cycle side is rightly connected to the power supply bridge rectifier and also to PNP transistor emitter through a resistor, and its collector to the negative rail of the power supply.
Can someone explain to me what is happening? I appreciate your help. Thank you.