121b

Clearly you have something wrong in the HF circuit, which is pretty simple. I would look at contact integrity on the HF balance control (i.e. loose or corroded connections). You might also check the (2) large, .01-uF capacitors on the PCB board. Those capacitors (along with the 50K-ohm resistors) blend the outputs of the LF and HF audio transformers. Perhaps one of those capacitors has gone open circuit. You may also have a bad HF transformer, which is best checked by swapping with a known good HF transformer.
 
thank you for your help. cheers
made my frames out of wormwood with plywood sandwiched in between for strength. wormwood had no strength but looks cool. varathane gloss.
going to cover the panels with copper wire like the speakers in the rear.
 

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