1948 GE Model 62 Clock Radio having issues

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1948 GE Model 62 Clock Radio having issues Empty 1948 GE Model 62 Clock Radio having issues

Post by CaptainClock on Wed Jul 19, 2017 12:33 pm

Hello everyone I've been working on a 1948 GE model 62 Clock radio for a buddy of mine that the unit I have completely recapped the unit but when I went to power it on to check my work the radio would oscillate but wouldn't pick up any stations unless I messed with the antenna. Any ideas as to what's going on with the unit? I checked the tubes and they all checked out ok, so its not a tube issue, I don't think, unless a tube could test good but be faulty.

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1948 GE Model 62 Clock Radio having issues Empty Re: 1948 GE Model 62 Clock Radio having issues

Post by Tony V on Wed Jul 19, 2017 9:59 pm

Some radio's are sensitive to wire routing and will cause oscillation and motorboating if moved. You can try moving the wires around a little with a non-conductive rod or something like a popsicle stick and see if you can improve it that way. Also check your antenna connections on both ends and make sure they are secured properly.
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Post by jsweinrich on Wed Jul 19, 2017 11:22 pm

What appears to be internal oscillations may just be modern digital electronics nearby. Even USB chargers emit a ton of RFI. This can be exasperated with poor alignment in the RF and IF stages. This is especially true if the IF is not properly aligned. A de-tuned IF makes the receiver less sensitive and susceptible to a broader range of signals (RFI).

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1948 GE Model 62 Clock Radio having issues Empty Re: 1948 GE Model 62 Clock Radio having issues

Post by CaptainClock on Thu Jul 20, 2017 8:54 pm

Well, here's the thing, one of the wires that went to the built-in loop antenna on the back of the radio's back cover broke loose from the contact that it was attached to which attached to one of the loop antenna connections on the radio's back cover, which I had to strip and resolder the wire back to the terminal but of course the amount of wire that was given you to work with for the connection was not much so when I reattached the wire the back cover didn't have much room to move around because the wire lead had very little slack compared to the other two wires for the antenna connections. Also the wire that was used for the built-in loop antenna got snagged on one of the lugs for fastening the back cover of the radio to and tore the wire loose from the back of the radio cover so the wire for the loop antenna isn't exactly lined up like it should be and is actually currently being held into place by scotch tape because it wouldn't hold to the original shape of the loop antenna anymore because the wire got bent. So would that cause the issues I'm having with this radio?

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Post by jsweinrich on Fri Jul 21, 2017 4:23 pm

Captain, it is a bit hard to know where your problem originates as I'm not there to poke around. I would start by doing the usual troubleshooting tests. Ground the audio signal at the volume control to verify that the oscillations are not in the audio section. If the oscillation stops chances are that the oscillations are generated upstream from that point. Next would be to ground the first IF amp control grid through a 0.1 uF cap. If oscillations stop then the the RF section is probably at fault. Does the oscillations stop when you pull the converter tube? RF amp tube?

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Post by CaptainClock on Fri Jul 21, 2017 11:14 pm

Well I already explained that the radio works fine when the antenna is moved a certain way, so it has something to do with the antenna circuit.

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Post by jsweinrich on Sat Jul 22, 2017 11:18 am

Sorry, I got the impression that possibly abnormal oscillations were affecting you receiver sensitivity. Have you tested for continuity through the antenna circuit? I would also perform an alignment just to make sure none of the RF and IF circuits were not affected by your recap, only takes a modulated RF generator and a voltmeter, schematic usually comes with a procedure.

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Post by CaptainClock on Sat Jul 22, 2017 6:09 pm

I don't have an RF Generator just a voltmeter. Although I thought about it a bit and I think maybe part of my problem might be because my workshop is in the basement of my house and I've noticed that basements are horrible at getting stations in, So maybe that might of been my problem, too, of course the only way to check that is to try it out upstairs in my office on the main floor of the house to see if it picks anything up without me having to monkey with the antenna.

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