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ms660 · 2nd May 2016, 11:19 am

The resistors that form the bias potential divider chain are just about in the ball park except for R16, the resistor that develops the bias rail (R21) is spot on.

I would suggest replacing R16 then measure the -ve voltage across R21 again and all the tapping points of the potential divider, then to make sure that V4 isn't absolutely doing it's nut measure it's grid bias voltage again and then it's anode current by disconnecting the output transformers HT feed and connecting your meter set to 100 mA DC or whatever in series with that feed, It should give a better idea as to what's going on.

Lawrence.

2nd May 2016, 11:19 am	#122
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: HMV 653 Broadcaster all wave. The resistors that form the bias potential divider chain are just about in the ball park except for R16, the resistor that develops the bias rail (R21) is spot on. I would suggest replacing R16 then measure the -ve voltage across R21 again and all the tapping points of the potential divider, then to make sure that V4 isn't absolutely doing it's nut measure it's grid bias voltage again and then it's anode current by disconnecting the output transformers HT feed and connecting your meter set to 100 mA DC or whatever in series with that feed, It should give a better idea as to what's going on. Lawrence.