1946 Lincoln radio parts and repair help

[46 Lincoln EFN]

Hello all ,

Im working on my radio , and it seems I may need parts or a helping mind .

Does any one have Experience in fixing these , or  know where I can get replacement parts? I do have a backup radio and the schematic , but I would like some Guidance if at all possible
Thank you all, 

Everett 

[Rusty_OToole]

Are there any tube electronics or tube radio enthusiasts in your area? Car radios are very much like any household radio with the addition of a vibrator for high voltage AC.

Tubes are pretty durable, and there are NOS replacements available if needed. The big issue is usually capacitors, they have a limited life especially the old original wax paper jobs. But, they can be replaced with modern, much more durable Mylar jobs at low cost. There are specialists on the net who sell the capacitors of the correct value for old radios, which may be different from modern electronics.

[Bloo]

I have no experience with that Lincoln radio, but quite a bit of experience with 1940s radios. Generally speaking, any radio with a vibrator will need it's buffer capacitor replaced before attempting to power up. It's capacitance is fairly critical. Don't try to match the working voltage. Higher is better.

 

Additionally, any paper/wax capacitors should be replaced. There is residual acid in the paper from manufacturing, and the paper disintegrates. None are still good. When operated at higher voltages, they leak current from one plate to the other. There are certain places in the circuits where there is not much voltage, and one of these could still function, but the attachment of copper wires to aluminum foil internally is not great after 70 years in an acid-laced environment either. The best policy is to replace all of them. Use "film" capacitors for replacements. Match the capacitance, but you may still have some prewar values in 1946, so pick a close postwar value. For instance, use .022 for .02, .033 for .03, .047 for .05 and so on. Go higher than original on working voltage. There is no harm, and capacitors have shrunk in size so much that higher voltage ones get you bigger wires and more length. They will still be tiny compared to the old ones, but will be likely to fit better. Standard practice is to use 600V or 630V capacitors to replace the 250V, 400V, and 600V capacitors from days of old. Yellow axial film capacitors such as the CDE 150 (formerly Mallory 150) and similar capacitors should be a good choice, or the CDE (formerly Sprague) Orange Drop and similar. On any capacitor that was higher voltage than 600V, just match voltage or go higher. Any capacitor across the primary winding of an audio output transformer should be 800v or better no matter what the original was.

 

Electrolytic capacitors from the 40s, at least the ones in sealed aluminum cans can theoretically still work, but were not high reliability parts when new and should be replaced. Some people cut apart the cans and restuff them. Replacements tend to be cheaper and available in higher grades with radial leads. Axial are available. Match the capacitance, typically rounding up to get to a postwar value if necesssary. The same or higher will be fine for working voltage. Radial lead capacitors typically don't fit worth a damn in tube radios, but can actually be an advantage if you replace above-chassis cans with new electrolytic capacitors under the chassis. You might need to add terminal strips. A current manufacturer is Keystone. They might cost more than the capacitors. I prefer this method, but you may well not have space to do it in a car radio. In that case, you would have to either restuff the can, remove the can and mount the new ones above the chassis somehow, or buy a custom-made can.

 

Mica capacitors should be left alone unless proven bad. Tubes are highly unlikely to be bad, despite what most people seem to think, and are readily available if needed.

 

Some electronics suppliers where you can find capacitors, resistors, etc.:

 

https://www.newark.com/

https://www.mouser.com/

https://www.digikey.com/

 

And a couple more who cater to hobbyists and have all the right sort of capacitors (and resistors) in stock for vacuum-tube based electronics:

 

http://www.tuberadios.com/capacitors/

https://justradios.com/

 

Tubes:

 

https://vacuumtubesinc.com/

http://www.pacifictv.ca/

 

Custom replacement can-type electrolytic capacitors:

 

https://hayseedhamfest.com/

 

Edited May 6, 2022 by Bloo (see edit history)

[Frank DuVal]

On 5/5/2022 at 9:05 PM, Bloo said:

Generally speaking, any radio with a vibrator will need it's buffer capacitor replaced before attempting to power up. It's capacitance is fairly critical. Don't try to match the working voltage. Higher is better.

Ding Ding Ding  a winner of a suggestion. Always replace this capacitor.

 

If no one can see inside the radio, just replace the sections of the can electrolytic with tubular ones. You can leave the can in place, but DO NOT use it as tie points for the new capacitors if you do, as the existing sections can short, causing more issues.

 

As said, check for local radio clubs. Here in the mid Atlantic we have MAARC, Mid Atlantic Antique Radio Club , where you can get help. There are several around the country.

[JimKB1MCV]

+1 to all the above.

Its not rocket science but will require a bit of research if you haven't done a similar project.

 

Heres a site with available help :

https://antiqueradios.com/forums/

 

Good luck.

[radioguybill]

Hi Everett;

If your radio is a 7ML081 made by Zenith or the 7ML801 for Continental it's pretty straight forward. 

Make sure the solenoid for station selecting is activating and that all tuning gears are free and turning. It's a slug tuning tuner and each slug will tune to an individual station. Also a manual tune position by pulling out on tuner knob when in manual tune position

Use a mechanical vibrator initially when testing. Polarity will not make adifference using mechanical one. SS vibrator polarity sensitive.

If you're stuck on any particular issue post it or contact me.

 

Bill

Edited May 14, 2022 by radioguybill (see edit history)