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Posted By: Dakotabolt original radio not working - Sat Apr 30 2022 06:29 PM
I have an original 1948 3100 truck. The radio light comes on but no noise at all from speakers. Any pointers on getting it to work or know of anyone in western South Dakota to take a look?
Thanks !!

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Posted By: Rusty Rod Re: original radio not working - Sat Apr 30 2022 06:59 PM
My guess would be that something is burned out inside? At any rate, i'll move your question to the radio forum where the radio experts reside.
Posted By: klhansen Re: original radio not working - Sat Apr 30 2022 07:20 PM
Here is a link to some possible help for you.
Posted By: buoymaker Re: original radio not working - Sat Apr 30 2022 08:34 PM
The radio is 74 years old. Components inside simply age out.

To give a little more insight on what typically happens:

The circuit that creates the higher voltage for the vacuum tubes has a oscillating mechanical device "vibrator" with contacts that usually corrode and stick over time.
There are several capacitors that most likely have aged and failed or changed value. Most are simply replaced with modern ones.
Rust, dirt, dust, spider webs, you name it. The radio will need a good cleaning inside.
The speaker cone and voice coil probably have dried out and cracked and need repair.
The tuner string usually ages and breaks. You notice this when you turn the knob but the needle doesn't move.
Even after doing the above you may hear pops and cracks while tuning like July 4th fireworks (microphonics) which can be caused by dirty, bad or corroded tuner bearings.
The list goes on....

This is why you want an experienced radio serviceman and not a computer tech to work on your radio.
Labor is a lot of the repair cost.
Posted By: truckernix Re: original radio not working - Sun May 01 2022 01:50 AM
The most common failure in these old radios is the vibrator. However there are capacitors which should be replaced, namely all the wax covered paper ones and the electrolytics in the silver can. I don't think this radio would ever have static from dirty bearings because the tuning mechanism is not a variable capacitor but an array of moving ferrite cores inside coils. The best approach is to replace all the above parts before trying to troubleshoot the radio. I have repaired numerous radios where the old tubes test in the good region and perform correctly.
Posted By: Dakotabolt Re: original radio not working - Tue May 03 2022 04:04 PM
Thank you for the pointers !!
Posted By: Mike Burns Re: original radio not working - Tue May 03 2022 05:19 PM
You have been given some good advice from some of these guys. In another life, I worked on stuff like these old radios. Since you said the light is on, your fuse is almost sure to be OK. Still would be silly not to check it. Of course, I would test all of the tubes before going any further, simply because it's quick and easy. It's hard to find a tube tester these days, but most communities have some old guy who works on old electronics for a hobby. He'll have one. If a tube checker says a tube is good, then it probably is. If a tester says it's bad, then it MIGHT be bad. Beyond that truckernix and bouymaker gave you good advice and I would follow it. If it were me, while I had the radio apart, I would change all of the old paper capacitors, and the electrolytics capacitors too. If they're not bad right now, they will be in the near future. Oh I forgot to mention, if your vibrator is working, you should be able to hear a faint humm from it, unless it's been replaced with a solid state vibrator. I would replace the vibrator while it's apart too.
Posted By: truckernix Re: original radio not working - Wed May 04 2022 12:00 AM
From the shot of your dash, the radio buttons and knobs look like they are in good shape. I am thinking maybe they are new and that the radio has had work done. You could take a photo of the inside and post it. That might tell us more. A bad vibrator will not allow the radio to work so maybe that may be your only problem.
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