Would C38 (if leaky) be a possibility? It is well buried in the chassis and I have not replaced yet.
Brian

:Sir Brian. . . . . .
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:On that set of your's, there is basically just the full B+ buss and the sub B+ buss.
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:If you will consult the attached marked up schema, one sees the RED MARKUP B+ moving to the right from its derivation at the rctifier toobie. Then upwards, to feed that full supply level to the AF output tube supply.
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:Further tracking of that buss, transversuing to the left, has a minor tap off to further drop the B+ to the early stage AF tube. Next stop to the left is a full supply B+ level to the target anode of the eye tube.
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:To the left from that last area is the feed to the plate of your 6K7 if amp tube along with a further path to the left to the plate of the hexode portion of the 6K8.
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:Now, in going back to the sub B+ buss, it is derived from a voltage divider bridge of R14-R17 [YELLOW]that ties into the main B+ buss.
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:The sub B+ power flow is to the left via the FUSCIA MARKUP it branches apart to feed the screen grids of the 6K7 and the 6K8 on one run.
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:The other run feeds over to the left and then up to the plate of the oscillator section of the 6K8.
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:The sub B+ level would be dependent upon the main B+ level, the ratio of the R14-17 divider resistors or the current consumption of the tubes tied in to it.
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:Seems like a slight fault with the sub B+ level as it now stands, are R14 and R17 to spec ?
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:On the other aspect, of the 300VDC level on the main B+ buss , a wee bit high, but I do consult with the RCA Radiotron Tube and Design manual and see the 6K8 being used up to the mid to high 200V levels.
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:Matter of fact, in its compared performance with 100 VDC on the plate of the hexode , the conversion efficiency amd overall performance is appreciably better when using the higher voltage.
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:An aside thought, since I am uncertain about WHICH post, recently, and WHO it is / was . . . in which case was the mentioning of the use of a 1 K value power resistor in place of a field coil on a radio.
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:Should this happen to be the set involved, the reason for the higher derived B+ voltage just might be due to the
:use of a 1K value of power series dropping / filter resistor. The value should be 1,500 ohms instead.
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:73's de Edd
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