In Reply to: PL504 posted by Ralph on January 9, 2019 at 10:49:18:
Hi Ralph, Appreciate the help but the tubes are available and OK. The dealer suspects the issue lies in a mystery circuit that is only specified as an 'output device' on the diagrams. Looking at posts on the GM200 I suspect that this circuit may involve a varistor. I am trying to contact Graaf.
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