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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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25th Jun 2020, 1:49 pm | #1 |
Pentode
Join Date: Dec 2017
Location: Staines-Upon-Thames, Surrey, UK.
Posts: 122
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CCT Diagram Missprint??
I'm working on an Ultra R906.
Going through the DC voltages and my measurements are not agreeing with the circuit diagram. Is it me, the set or the diagram that's wrong? V2/p2 = 8.5v. I measure around 85v. IFT2 primary=8.5R. Must be a misprint. V3/p5 = 11v. I measure around 22v. R10 is definitely 820K and it has 42v across it. So the current through R10 and hence V3 anode = 0.05mA. This seems very low - is it correct? Can anybody please advise? Thanks, HowardB |
25th Jun 2020, 2:19 pm | #2 |
Octode
Join Date: Aug 2003
Location: Welwyn Garden City, Herts. UK.
Posts: 1,906
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Re: CCT Diagram Missprint??
V2 anode voltage should be 85V so yes its a misprint.
V3 anode is at very high impedance ant measured with an AVO 7 in the manual I believe so may measure 11V with that. Any other higher impedance meter will measure higher so I expect your reading is OK. Yes with anode load of 820K the current will be low. All those battery designs were. |
25th Jun 2020, 2:25 pm | #3 |
Pentode
Join Date: Dec 2017
Location: Staines-Upon-Thames, Surrey, UK.
Posts: 122
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Re: CCT Diagram Missprint??
OK, so everything's good, many thanks Peter.
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