RCA 61-7
11/13/2013 12:05:10 PMRay(109277:0)
SO Iv got a couple of these and they both have the same hum, I can turn the sound down and they still hum through the speaker, Is this common on this radio? Maybe they need some kind of filter? Any Ideas.
11/13/2013 12:41:21 PMjim l(109278:109277)
:SO Iv got a couple of these and they both have the same hum, I can turn the sound down and they still hum through the speaker, Is this common on this radio? Maybe they need some kind of filter? Any Ideas.
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I u turn volume fully counterclockwise and stiil have hum, means the electrolytic capactors need replaced
11/13/2013 12:46:05 PMCV(109279:109277)
Most inexpensive (AA5) tube radios had marginal power supplies and some amount of "DC ripple" hum is normal. This is kind of subjective. If the hum is noticeable from several feet away, there is probably a problem with the set(s). Since hum is present with the volume control at minimum, the most likely culprit is weak filter capacitors. Hum can enter the set from other exteranl/internak sources but if so, it would be riding on the audio signal and would be suppressed (along with the audio) with the volume control set to minimum.
11/13/2013 12:46:08 PMCV(109280:109277)
Most inexpensive (AA5) tube radios had marginal power supplies and some amount of "DC ripple" hum is normal. This is kind of subjective. If the hum is noticeable from several feet away, there is probably a problem with the set(s). Since hum is present with the volume control at minimum, the most likely culprit is weak filter capacitors. Hum can enter the set from other exteranl/internak sources but if so, it would be riding on the audio signal and would be suppressed (along with the audio) with the volume control set to minimum.
11/14/2013 5:22:52 AMRay(109302:109280)
:Most inexpensive (AA5) tube radios had marginal power supplies and some amount of "DC ripple" hum is normal. This is kind of subjective. If the hum is noticeable from several feet away, there is probably a problem with the set(s). Since hum is present with the volume control at minimum, the most likely culprit is weak filter capacitors. Hum can enter the set from other exteranl/internak sources but if so, it would be riding on the audio signal and would be suppressed (along with the audio) with the volume control set to minimum.
:Iv replaced the caps on one the other has old caps they both make the same noise, maybe I got a bad new cap? So I guess I should find the filter
and check it. Thanks
11/14/2013 7:19:46 AMCV(109304:109302)
It's not likely that you got a bad new cap. If you used one that had been sitting in a parts bin for many years, it may have gone bad; but a newly-manufactured one is almost certainly OK. Did you get the polarity correct when you installed the caps? You might also check your work to make sure that they are installed in the right place. It's very easy to
make a mistake. You can use the untouched radio as a wiring reference for the one that was worked on.
11/14/2013 9:48:32 AMRay(109307:109304)
:It's not likely that you got a bad new cap. If you used one that had been sitting in a parts bin for many years, it may have gone bad; but a newly-manufactured one is almost certainly OK. Did you get the polarity correct when you installed the caps? You might also check your work to make sure that they are installed in the right place. It's very easy to
:make a mistake. You can use the untouched radio as a wiring reference for the one that was worked on.
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I know I did ok on the electrolytic cap, Looks like only one, the rest had no polarity? maybe there is a problem there.
11/14/2013 10:37:32 AMCV(109308:109307)
There were originally two electrolytic caps in one can. One is 50 uF, the other is 30 uF. Both need to be replaced to minimize hum. The non-electrolytics are not polarized and their orientation doesn't matter.
11/14/2013 1:53:23 PMRay(109310:109308)
:There were originally two electrolytic caps in one can. One is 50 uF, the other is 30 uF. Both need to be replaced to minimize hum. The non-electrolytics are not polarized and their orientation doesn't matter.
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Yup I replaced the two in one but it was a little diff. One leg was 47 uf and one 33 uf both at 160v. Maybe that has something to do with it?
11/14/2013 2:01:27 PMCV(109312:109310)
Close enough; and the voltage rating is OK, too.
11/14/2013 2:06:19 PMRay(109313:109312)
:Close enough; and the voltage rating is OK, too.
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Ok thanks for your time and input, Ill let you know if I find something. Mean while Im just going to listen to them.