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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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3rd Nov 2010, 2:57 pm | #1 |
Retired Dormant Member
Join Date: Oct 2005
Location: Reading, Berkshire, UK.
Posts: 21
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KB ER30 problems
After many years of regular trouble free use this old box of tricks has developed a sickness. It has always performed perfectly; no loss of power, no crackles, no noisy switches-everything A-0K but now it will only go for about 10 minutes before it acts as if the volume control has suddenly gone down the tubes. The programme can still be heard faintly and some knob twiddling brings it back intermittently before it finally reverts to a whisper. I suspect it must be something heat-related.
Any suggestions from the experts out there? |
3rd Nov 2010, 3:16 pm | #2 |
Dekatron
Join Date: Sep 2003
Location: Bolton, Greater Manchester, UK.
Posts: 6,644
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Re: KB ER30 problems
It could be a number of things, but the first thing I would do is replace THAT capacitor and any other waxies that may be left inside it.
Then check for loose connections and dodgy soldering joints which fail when warm. Then go round the valves you have and measure voltages before and after the fault occurs. There is a sheet available here: http://www.service-data.com/product.php/3192/4145 Cheers, Steve P.
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If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...? |
3rd Nov 2010, 4:08 pm | #3 |
Heptode
Join Date: Mar 2010
Location: Eastham, Wirral, Merseyside, UK.
Posts: 788
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Re: KB ER30 problems
As Steve said change that cap+the waxies.before you do, you could switch the set to gram put a signal in the gram socket to test the amp,if it is the amp change (C 21 coupling cap to pin 7 6V6GT)very common in this set,and the circuit above is only £1.99 Email delivery is exellent.hope this helps Gezza
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3rd Nov 2010, 6:38 pm | #4 |
Pentode
Join Date: Nov 2005
Location: Tircoed Forest Village - Swansea, UK.
Posts: 193
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Re: KB ER30 problems
Should we be posting a sticky regarding 'that capacitor' ? Maybe we have and I've not seen it. Slap my hand if I missed it....
Bob W
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4th Nov 2010, 1:49 am | #5 |
Dekatron
Join Date: Jan 2003
Location: Bradford on Avon, Wiltshire, UK.
Posts: 3,310
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Re: KB ER30 problems
Also check valve top caps,audio amp valve (6Q7G?), and anode resistor thereof.
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4th Nov 2010, 11:15 am | #6 |
Retired Dormant Member
Join Date: Oct 2005
Location: Reading, Berkshire, UK.
Posts: 21
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Re: KB ER30 problems
Many thanks for all your erudite suggestions; now I just hope that I can get all those horrible knobs off so that I can get inside to do the operation!
Richard |
4th Nov 2010, 1:26 pm | #7 |
Dekatron
Join Date: Jan 2003
Location: Bradford on Avon, Wiltshire, UK.
Posts: 3,310
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Re: KB ER30 problems
They probably just pull off, but rotate and check for screw holes.
If the former you may have to resort to the string/handkerchief trick.
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"Nothing is as dangerous as being too modern;one is apt to grow old fashioned quite suddenly." |
4th Nov 2010, 11:07 pm | #8 |
Heptode
Join Date: Mar 2010
Location: Eastham, Wirral, Merseyside, UK.
Posts: 788
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Re: KB ER30 problems
Yes they pull off,the best way I found was to use a long thin screwdriver and take of the clips off first, then push them off from the inside ,also make shure you have something or someone to catch them as they fly out,don't try to pull them from the outside as these knobs break very easy in the centre.and you may be looking for some new ones ,good luck.Gezza
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