Started working on my 37-60B after 2 years. Last time I posted my step-mother died a couple of months later, been busy with some issues. Anyway, found that someone wired a new #42 cap (8 uF) in wrong. Reckon they assumed the crossover on the schematic was a tie point. See last picture.
Have a question about #29, supposed to be a .015 uF cap, but a .005 is installed. Anybody know why a different cap is installed? Some change I don't know?
Also, on the base view of chassis, # 17 & 32 on the far right are interchanged.
Went thru several "foil side" Youtube videos. After trying a few methods I stopped, couldn't tell a difference. I'll be happy to just get it working.
1 #'s 42 and 44 do not have the positive sides connected together. The speaker's field coil goes in between them.
2 # 29 being replaced w/a .005 vs .015mfd will not cause any harm nor will it stop it from working. What it will do is low the volume slightly and diminish the low frequency response a little.
3 I wouldn't worry about the foil side vs the non foil side.
Spec for the resistors is/was 20% so there's a fair amount latitude in range of value.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
(This post was last modified: 05-09-2023, 09:15 PM by Radioroslyn.)
Thanks a bunch. Trying to go through my radio and check actual conditions against schematics.
It seems to have most of the updates, but someone has been working on it. Already found a clipped capacitor end that had fell against 2 tube terminals. Taking prior advice into account for not powering up radio until I finish.
21 ohms is probably the way it has always been since there usually is not a lot that can change the resistance of a coil wire other than a short or open. Its not like a resistor that drifts, at least from what I've seen.
Those four caps you can't find are mica trimmer capacitors inside the IF transformers. They are adjustable and are usually accessible at the top of each transformer. Check the IF alignment procedure for instructions on what to do with them.
Hello Bryan,
Good luck on your repair and make sure you check the resistors for any that are way out spec and double check your work as you go along.
I really do a lot looking over the set after I do a restoration before apply power again cut off leads and solder really loves to hide in radios .
Sincerely Richard
P.S. take your time and enjoy restoration .
Thanks all for the advice! I'm trying to be real careful since someone has been into it.
This morning's work for 2 hrs til my brain fried.
Was tracing the update junction of part 19 (9K resist), 18 (20K resist) and top of 20 (16 uF cap). The junction goes to part 34 (70K), then to 35 (.01 uF) (where someone thought it was 40 and put in .03. I'm sure of this.
On the original base view of chassis it is marked as 40, guess that confused them. Sure did me.
Other problem is when I started tracing from the volume switch (pot). Was driving me nuts, I thought 40 & 41 were hooked to it, but it actually looks like some optional headphone jack. It has a switch, and an RCA jack. Am I correct?
Bryan
PS: seems it's impossible to get the pictures in the correct order.
Not sure what you have going on but the original circuit goes like this. 47,40, and 41 are the three position off/on switch and tone control. That's what 40 &41 do. Was no headphone jack or audio input jack. It's not uncommon for the tone control switch to break.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
There's definitely an RCA type connector on it as I drew.
Finished for today. Cleaned out the Bakelite case 46 with brake cleaner. Loosened the bias resistor 43 and slightly rotated it out of the way to get to the end of capacitor 35. Don't want to solder at the tube terminal.
The radio / Phono switch and RCA Jack are likely mods. These were very common as many manufacturers sold phonograph attachments without amplifiers. The fact that it is an RCA jack means that the mod was made sometime after 1940 or so.
Make sure that you clean the switch. This mod is very handy as it is a great "divide and conquer \" point. Connect a computer or MP3 audio (or a phono) to this jack, switch to phono and fire up the radio when you have sufficiently checked the radio out. Good audio indicates that the audio section works. Bad or no audio indicates that you start troubleshooting there and / or at the power supply.
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
Best Regards,
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