VCCA Home Forums TECHNICAL - GENERAL Radios, Tools, Accessories 46 Truck Radio Question

Hi
I have a question about the radio originally used in a 1946 Chev truck.

The information I have says the Model 985792 was used from 1942 to 46 and mounted under the dash to the left of the steering column. This radio had the speaker inside the actual radio case and facing downward.
The Model 986146 radio apparently was used in 1947 and 48 and looks almost identical except the speaker was outside the case and mounted on top of the radio in the dash. And it was a little different color. This radio seems to be more common.

My question is this:
Can the later 986146 radio be converted to a 985792 by mounting a/the speaker inside the case?
I can deal with a different color, but the speaker is another matter.

Thanks very much for your expertise.
Ole

Too bad you are across the barrier or I could fix you up in a few minutes. If you are good with your hands or have an elictrical friend, you can make the change yourself. If you get into a problem, send me an email (chev33radio@comcast.net) and we can send each other pictures. We can get it done.

So it can be done then!
I wondered if there was enough room inside the later radio for the speaker.
Thanks very much.
Ole

https://www.ebay.com/itm/223875124784

Here is a speaker conversion kit with the two radio #'s you mentioned...although i think it may be the other way around

Thanks BetoB
But judging by the part number being 1 number higher than the newer radio number, and it saying it's for the older radio, I believe you are probably right in it being a conversion going the opposite way.
Thanks just the same.

I have seen some of these radios with octal tubes, some with loctal tubes, and some with a mix of both. If at all possible, look for the octal tube version of the 985792. The loctal tubes and sockets suffer from poor contacts and will cause the radio to stop working over time. Please google octal vs loctal tubes for the details.

I really know nothing about radios, but I looked that up and I'll watch for it.
If I read it right, The number of the tube will give away which type of base it's on, correct?

That is correct. If the tube numbers start with 7, they are loctal. If that is what you have, hopefully you will be lucky and the radio will just work as it's supposed to. I was not so lucky. My radio had one loctal tube and the rest were octal. I had intermittent low reception issues that I traced back to the tube socket. I twice cleaned the socket and tube pins thoroughly. The radio would work on the bench but had problems in the truck. I finally replaced the tube and socket with its octal equivalent and all my problems went away. The loctal tubes are good tubes internally but their pins and sockets leave much to be desired. I know other 40s Chevy owners that have reported the same problems. Good luck.

Hello coachman28
I think I may have found a working 985792 radio!
Seller says it works well. I will of course believe that when I have it in hand and see it with my own eyes.
I've been doing a little research on the interweb and found some old info that says these radios (if I'm reading this right) were manufactured with all octal tubes until serial number B46-136523. At that point the 6SA7GT oscillator-translator tube was changed to a 7Q7 type.

So am I correct in thinking that from that time forward these radios had 1 loctal tube and the rest octal as with your radio?

The radio I've found is below that serial number, so unless it's been monkeyed with I'm hoping it is all octal.
Thanks for the info!

Ole

Ole, that is some good information. Could you share the source for our benefit? The oscillator tube was the only loctal tube in my 985792 radio and according to my records, the serial number is B46-142216 so that is consistent with the information you found. I went out to the shack and checked a parts radio. I was thinking it was also the 985792 model but actually it is the 986146 model with internal speaker retrofitted. Its tube compliment is completely loctal. The serial number of that radio begins with B48- and the rest is illegible.

Best of luck on your radio.

coachman28
I think the place I read that was here:
https://www.tubesandmore.com/schematics/chevrolet-div-general-motors/985792

Not a lot of info there but it does state that at serial number B47-1001 they changed 3 more tubes to loctals leaving only the OZ4G (rectifier tube??). That agrees with what you found in your B48- as well.
It also points out a change in resistance in 1 resistor and a changed location for 1 capacitor at an earlier serial number in the 985792 radio.

I still really know nothing about these things... but I'm trying.

Ole

I think you are quickly becoming an expert. Thank you for sharing the link to Rider's. That link includes a page I was missing.