| Re: ICA AC Companion Radio [message #89647 is a reply to message #89637] |
Tue, 29 January 2019 13:16   |
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Wayne Parham
Messages: 18680
Registered: January 2001
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Illuminati (33rd Degree) |
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I love these old tube radios. I have some Sam's Photofacts and a collection of CDs with thousands of schematics of old tube radios. I'm going to try to find your radio on one of them. Gotta find the disks first though - I haven't repaired a tube radio in about ten years.
I was on a tube-radio collecting kick about 20 years ago. My first radio looked great, but the electronics were in really bad shape. It had been repaired during WWII - from a date on a repair tag on the chassis - and had an output tube that was different than what was shown in the schematic. I imagine the technician didn't have the right output tube, so he re-wired the chassis to use a tube that he had on hand.
If that was the only problem, it would have been cake. But all the capacitors were open, and the insulation on the wires was brittle and cracking off, leaving exposed conductors. So I bought a couple spools of cloth-insulated wires and rewired with that. As an aside, I like cloth insulation in tube radios 'cause it'll last a hundred years.
If the wiring and the caps were the only remaining problem, it wouldn't have been too bad, but I still had no high voltage... Because the field coil was open. Now I could have just replaced the speaker with a fixed magnet and run a resistor in place of the field coil but I really wanted the radio to be "right" so I wound the field coil myself. Couldn't just wind it like you would on an open spool either, because the speaker frame prevented that. I had to push the wire through the side of the frame and then wrap it around for each and every turn. That's a repair I had to fight for. And in the end, I'm most proud of that radio.
I bought maybe a dozen tube radios after hat one. None were anything close to that much trouble. In fact, one or two worked without any repair needed. But I replaced all the capacitors anyway. Several other radios would have worked except the PS caps were bad. So I always replace them with poly caps. Most are 20uF to 40uF, and a poly cap is about the same size, so that's an easy fix.
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