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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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19th May 2009, 4:15 pm | #21 |
Dekatron
Join Date: Sep 2003
Location: Bolton, Greater Manchester, UK.
Posts: 6,644
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Re: Grundig 2043 gets louder after 1 hour. Ignore/Worry?
Why not put a resistor in series with Pin 1 of the magic eye valve. Might enable you to see what's happening.
Cheers, Steve P.
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19th May 2009, 5:33 pm | #22 |
Dekatron
Join Date: Feb 2007
Location: Lynton, N. Devon, UK.
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Re: Grundig 2043 gets louder after 1 hour. Ignore/Worry?
Measuring between pin 1 (negative) and pins 2&4 (positive) will tell you what the magic eye is seeing, even after it's fully open. Use a DVM or something with a very high input resistance.
The advantage of looking at the magic eye's DC signal input, is that it's a nearly infallible indication of the signal strength reaching the detector. Incidentally, I can't see Steve P's sugestion doing much - as pin 1 is the grid, adding a series resistor won't affect anything. Or (always possible!) does he know something that I don't? |
19th May 2009, 5:38 pm | #23 |
Dekatron
Join Date: Sep 2003
Location: Bolton, Greater Manchester, UK.
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Re: Grundig 2043 gets louder after 1 hour. Ignore/Worry?
I thought that it might make the reading go down, so that it could be read. Might be complete tripe, but it seemed to be worth a shot.
These sort of faults are hard to find, and with the set out of the cabinet, the problem might not appear.... 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...? |
19th May 2009, 6:15 pm | #24 |
Dekatron
Join Date: Feb 2007
Location: Lynton, N. Devon, UK.
Posts: 7,061
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Re: Grundig 2043 gets louder after 1 hour. Ignore/Worry?
OK.
Adding a series resistor will reduce the sensitivity of the magic eye - provided another resistor is connected directly between pin 1 and pins 2&4 (which are chassis). I'd suggest 2.2megohms in series, and 1 megohm in shunt. Yes, removing the chassis may make the fault not happen! And at the moment, we don't even know if the 'loud' condition is normal, with the preceding 'quiet' being wrong, or vice versa! |
19th May 2009, 6:51 pm | #25 | |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
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Re: Grundig 2043 gets louder after 1 hour. Ignore/Worry?
Quote:
This won't identify the fault though. All the advice about checking circuit voltages when the fault is present is still good. Treble check that you haven't missed a capacitor somewhere Paul |
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20th May 2009, 10:17 am | #26 |
Hexode
Join Date: Jul 2008
Location: Toulouse, France
Posts: 406
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Re: Grundig 2043 gets louder after 1 hour. Ignore/Worry?
Hi !
I own a couple of 3397 stereo sets from Grundig. This morning, I came across a behaviour like the one you describe except it is in reverse. I turn the set on, and after about a quarter of an hour, the volumes goes down. (about half the previous level) Funny I thought as I was reading the forum ! So I turned the set off for some time (to get a coffee and an apple...) and repeat the experiment. It came as the first time. The magic eye did not move (it was at 100%) and it took 20 minutes. the set did not revert to the previous level. I turned up the second set and, guess what ? The second set behaves like the first one. §But the variation in level is less, and the time is shorter. About 10 minutes. As many Grundig sets share a very similar radio part, you may have a clue ;-) or at least a lead to follow... I, for one, will let the two sets as they are. For now I'm not going to do radio repair for some days... Maybe a recent bad experience ? Who knows :-; |