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 Post subject: Alignment with no user manual/schematic?
PostPosted: Nov Sun 26, 2017 4:38 pm 
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Joined: Mar Mon 27, 2017 4:29 pm
Posts: 52
Can some of you transistor radio experts explain how you align a radio if you can't find any user manual/schematic?

Is there a way to do it "by ear" with strong and weak stations on the top of the dial? I've seen some references to this here but don't know the whole procedure you might use!


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 Post subject: Re: Alignment with no user manual/schematic?
PostPosted: Nov Sun 26, 2017 4:47 pm 
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Joined: Jul Mon 26, 2010 8:30 pm
Posts: 20677
Location: Annapolis, MD
" where there is a will, there is a way."
The first thing to do is identify all of the adjustments. Is the radio AM only, or AM/FM?

If you can post some good closeup pictures, we can help you figure out what is what. But also tell us the make and model, and maybe we'll find a schematic.

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 Post subject: Re: Alignment with no user manual/schematic?
PostPosted: Nov Sun 26, 2017 6:58 pm 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Utica, NY 13502 (USA)
Like Mark said, you first need to identify the adjustments and know what they do. For AM single band, single conversion superhets, the most important part is to get the IF transformers peaked to the correct frequency. This usually requires a signal generator. If you just arbitrarily peak the IF's, proper dial and RF tracking may be impossible to achieve. The rest can be done by "ear" if you have stations near the top and bottom of the dial. I wouldn't try aligning a multiband or double conversion radio without an RF signal generator that covers the frequencies involved.

Dave


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 Post subject: Re: Alignment with no user manual/schematic?
PostPosted: Dec Tue 05, 2017 7:49 am 
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Joined: Sep Thu 23, 2010 6:37 am
Posts: 9419
Location: Powell River BC Canada
The low end adjustment on some radios involved sliding the coil on the ferrite
bar. Look for some seal paint/wax, and see if the coil can easily be moved.

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de
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Amateur Radio Literacy Club. May we help you read better.
Steve Dow
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 Post subject: Re: Alignment with no user manual/schematic?
PostPosted: Dec Tue 05, 2017 12:31 pm 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: SoCal, 91387
radiotechnician wrote:
The low end adjustment on some radios involved sliding the coil on the ferrite
bar. Look for some seal paint/wax, and see if the coil can easily be moved.

For AM, this would be the starting point.

AM IF cans generally have black, white, and yellow cores. tune the set to a weak but non-fading station, ideally before sunset, and using a non-metallic blade, very slightly adjust each core, no more than a quarter turn, to achieve the loudest volume. Usually only one will do that, but you need to try all three to find it.

For RF alignment, the back of the tuning capacitor will have two trimmer adjustment screws, one for the oscillator gang, the other for the antenna gang. Tune the set to a station as close to 1400 Kc as possible, and then very slightly adjust one of the screws. If the station disappears, re-adjust to get it back, as that's the osc screw, and go to the other screw. Adjust for loudest volume.

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