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Old 16th Sep 2019, 12:53 pm   #48
Argus25
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Join Date: Oct 2016
Location: Maroochydore, Queensland, Australia.
Posts: 2,679
Default Re: Yet Another Bush TV22

Quote:
Originally Posted by peter_scott View Post
It doesn't appear to be a valve fault because half a dozen different ECL80s all display the same frame ripple and the cathodes are at ground potential. I did push the heater wires about this morning and did achieve a quieter sound intrinsic but have yet to see any frame improvement.

Peter
Its been a while since I looked at the schematic and yes not likely heater-cathode leakage in this case.

Of course the frame amplifier has a good response at mains frequencies and the resistances are high, so the wiring leading to the Hold,Height and LIN controls could easily pick up signals from other nearby wiring, like the heater wiring.
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