Zenith PRO 841x/851x

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HV board

Here is the HV board that does fail once in a while. Zenith had a bad run of these boards back in the 90s sometime, and the HV transformer would short out internally. Most of these boards have failed by now, but the HV transformers do develop internal arcs from time to time, resulting in an occasionally awesome flame show as the arcs come to the outside of the transformer.

It is easy to interchange the two 4 pin module connectors going to the deflection board. If the connectors are interchanged, the HV board will die and usually the power supply smokes as well. The HV board unclips from it’s holder and will turn and slide out the side of the set. It takes a bit of twisting and turning, but that saves taking out the whole deflection board… Don’t forget to connect the HV transistor when replacing the HV board.