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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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6th Dec 2019, 2:00 pm | #1 |
Triode
Join Date: Apr 2004
Location: Glasgow, Scotland. UK.
Posts: 15
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Ekco A22 low volume
Hi,
My A22 initially presents with low volume. Touching the EF39 cap with a screwdriver resolves the problem - until the next time I switch on. All the capacitors are relatively new and do not seem faulty. I have also replaced valves but still have the problem. A point in the right direction would be much appreciated ! Many thanks, Iain |
6th Dec 2019, 5:18 pm | #2 |
Dekatron
Join Date: Sep 2005
Location: Seaford, East Sussex, UK.
Posts: 5,997
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Re: Ekco A22 low volume
Have you tried another EF39? Is the metalisation in good condition? Have you cleaned the valve pins and socket?
This is the grid of the IF valve so I would be looking at IF instability or possibly the AGC resistors have gone high. |
6th Dec 2019, 5:40 pm | #3 |
Triode
Join Date: Apr 2004
Location: Glasgow, Scotland. UK.
Posts: 15
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Re: Ekco A22 low volume
Thanks for your advice. Yes, I did replace the EF39 with a known quantity ie out of my other A22 but no different. Strangely, the set will run happily for hours after the “ kick start” but once switched off for a period it reverts to low volume.
Iain |
7th Dec 2019, 10:18 pm | #4 |
Nonode
Join Date: Oct 2017
Location: Bristol, UK.
Posts: 2,384
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Re: Ekco A22 low volume
Hi Iain, try cleaning the wavechange switch contacts and also the extension speaker switch contacts, and check the continuity at the ends of the braided speaker leads. Touching the EF39 grid can produce a thump that can temporarily override a dry joint somewhere. The other possible cause is that the EF39 is on the verge of oscillation for some reason. Re-check AGC decoupling capacitors and their chassis connections. Failing that, try to establish whether the audio stage is working normally under "low volume" fault conditions compared to normal conditions. Cheers, Jerry
Last edited by cathoderay57; 7th Dec 2019 at 10:32 pm. |
8th Dec 2019, 6:38 pm | #5 |
Dekatron
Join Date: Sep 2005
Location: Seaford, East Sussex, UK.
Posts: 5,997
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Re: Ekco A22 low volume
Try measuring the AGC voltage on (trader sheet) C15 with and without the fault condition.
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