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Restoring a 39-7
#2

Got a variac and a schematic and got into the guts of this yesterday. Three immediate problems:

1. Volume knob was scratchy. Needed disassembly to clean with DeOxit, that worked, but the power switch never worked again. I did get a modern replacement that went in fine.

2. The 0.01uf wax cap on the volume control fell off. This was replaced with a modern cap, all I had on hand was a mylar capacitor, should this be replaced with an electrolytic, or will this be fine?

3. A wire was dangling off of the I.F. trans assembly. After sweating over the schematic, I found its old location and reconnected it.

All else looked good, except one green wire started flaking off insultation material. Since I had it off anyway fixing the volume, I sealed it in shrink tubing.

The person who had this before me cleaned up the case real nice. They also replaced all the caps on the power side. There's still 3-4 wax caps in it that I need to get to.

I did bring it up on the variac slowly with no signs of a problem. At approx 80VAC the speaker started making static, a bit higher and a station was coming in loud and clear! It's not smoking either!

So I reassembled it and looked it over - it tunes great, sounds great except for some slight hum/buzz that changes with volume. I have it next to its sibling 39-6 I posted about earlier and know I know the speaker in the 39-6 needs to be re-coned.

Next up on this is figuring out what rubber spacers are needed for the pushbutton tuning assembly, swapping out the remaining wax caps. I also need to get a polarized plug and put a fuse on it.

Still, this is my first electrical repair and I'm quite pleased I was able to figure it out myself. After I wrap this one up, I'll tackle something a bit more difficult.

   


Messages In This Thread
Restoring a 39-7 - by rworne - 08-15-2013, 09:34 AM
RE: Restoring a 39-7 - by rworne - 08-30-2013, 02:18 PM
RE: Restoring a 39-7 - by jerryhawthorne - 08-30-2013, 02:27 PM
RE: Restoring a 39-7 - by rworne - 08-30-2013, 02:34 PM
RE: Restoring a 39-7 - by BrendaAnnD - 08-30-2013, 04:13 PM
RE: Restoring a 39-7 - by jerryhawthorne - 08-30-2013, 04:22 PM
RE: Restoring a 39-7 - by rworne - 08-30-2013, 05:05 PM
RE: Restoring a 39-7 - by morzh - 08-30-2013, 05:17 PM
RE: Restoring a 39-7 - by jerryhawthorne - 08-30-2013, 05:29 PM
RE: Restoring a 39-7 - by rworne - 08-30-2013, 05:52 PM
RE: Restoring a 39-7 - by Arran - 08-30-2013, 09:42 PM
RE: Restoring a 39-7 - by rworne - 08-30-2013, 11:32 PM
RE: Restoring a 39-7 - by Jamie - 08-31-2013, 01:36 PM
RE: Restoring a 39-7 - by rworne - 08-31-2013, 02:25 PM
RE: Restoring a 39-7 - by hunter2115 - 09-05-2013, 08:31 PM
RE: Restoring a 39-7 - by morzh - 09-05-2013, 08:38 PM
RE: Restoring a 39-7 - by rworne - 09-05-2013, 10:12 PM
RE: Restoring a 39-7 - by rworne - 10-22-2013, 08:49 AM
RE: Restoring a 39-7 - by Mondial - 10-22-2013, 08:54 AM
RE: Restoring a 39-7 - by rworne - 10-22-2013, 09:14 AM
RE: Restoring a 39-7 - by Radioroslyn - 10-22-2013, 04:53 PM
RE: Restoring a 39-7 - by rworne - 10-22-2013, 07:28 PM



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