38-62 - can't get the one station I want to hear!
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Howdy fellas -
Working on a 38-62 that gets stations strong except for one that I naturally want to hear, at 1440. I get all others above and below. I can hear this station just fine with all my other radios. Changed antennas, moved the radio to different parts of the house, all with the same results. Would a dirty contact on the tuner at this exact point be the cause? I've never run into this before where one specific station couldn't be heard. Not even a faint trace of it and another radio next it playing that location strong.
Regards,
Paul
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This is tough one, If the set has a loop antenna built in, you might try to rotate direction of set in anotherwise good reception area. Of course if stuff is cutting out at 1400 and there is no reception above it, could be a piece of whatever caught at the top o the blades of the tuning capacitor that you could dislodge patiently with a piece of paper between each gap. If it rubs, it is touching. Try, then come back.
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Paul
Have you aligned the set? As Codefox pointed out, what we need to know if the signal above and at 1440 comes through when you set your oscilaltor to that frequency.
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Paul Are all the tubes good and strong? A forum member told me when you can not tune in a station in a certain radio dial section a week tube is always the problem. It helped me on my Philco.
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I lean towards the dirty tuner theory. Be sure to clean the clip that makes contact with the shaft as well as checking for plate shorts.
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Thanks very much for the replies.
I can get stations above it. I have not aligned it because I have not yet learned how and do not have the proper equipment yet, although I have watched videos on how. Self teaching myself here and while I'm a quick learner I'm not at that point yet. It did not originally come with a loop antenna, just a long wire. I've since attached a loop antenna on the end of the wire which greatly improved reception but did not bring this particular station in. The station is only 7 1/2 miles away and comes in clear on all the other radios I own. I did test all the tubes on Hickok 500 tester.
I have not cleaned anything yet because I didn't want to take a shotgun approach. I'd rather learn how to methodically troubleshoot these so I can apply the knowledge to other radios in my very modest collection.
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You need to try alignmet. It is pointless to talk before you try. You may discover things while doing it.
Like the oscillator does not oscillate at some frequencies. Which could be the tube. Possibly.
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Don't want to butt in here, but could the AVC possibly be choking the station
down since it is so close? Probably extra-strong signal getting to the radio.
Jim
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I'd expect if the station is that close, he'd be getting lots of intermod and bleed thru, regardless of strong AVC voltage.
Typing out loud,
Chuck
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7 1/2 miles is not that close, normally I wouldn't think there would be overload unless the station were beaming down his throat with 50KW. However, there may be some merit to the AVC having a problem. It's possible he's got no AVC action at all, and the radio is overloading on a strong signal.
Does the station sound any better if you tune off center slightly?
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It does not come in at all. I've spent considerable time trying to hear the slightest hint of the station but nothing. I've got it now but it doesn't receive this station. I can get 650 WSM out of Nashville at night which is 811 miles from me. But not this local station.
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In that case, I would definately check to make sure none of the plates on the tuner are touching. This can be a challenge, as they are quite close together. Do you have static when tuning past this part of the band?
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Easy. Just put the ohmmeter across the tuning cap and see if it shows continuity.
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That can surely tell you if the plates are shorting.. but doesn't do much for un-shorting them.  Now THAT'S the challenge.
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First one needs to know if the short is even there. trying to catch a black cat in a dark room is a difficult task.
Unshorting difficulty depends on the radio.
In a radio like 70 or 90 unless a fin is totally mangled, it is not a problem at all - those are huge caps with huge gaps. Then take a small AA5 set...there is a challenge. a gap is like 0.2mm on either side of a fin.
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