Boy, this one goes back a few years. Early one morning in 1988 I was talking to Grady Richards (R.I.P.) at the Springfield, OH flea market and I spotted a 12-S-265 Zenith console down at the end of the isle with the chassis sitting in it backwards. I quickly wandered over and saw the chassis and speaker were there but the cabinet had been stripped and had an ugly black stain on the top, but when the fellow said $15 I quickly paid him and said I'd pick it up later.
Back in KY a friend said he'd work on it for me in exchange for one of my older computers. I don't mind the chassis work but the cabinet had me worried with the stain, but my buddy was going to strip and refinish his at the same time, so I thought that would be a good plan. Now, back then I was acquiring a lot of radios and even had a storage unit, so I wasn't too worried about that Zenith since it wasn't taking up any space at my house. But let this be a warning to anyone who tells someone
"there is no hurry." My friend eventually stripped his cabinet but the project sort of stalled right there.
Fast forward about 30 years to the last Kutztown show and I found a guy with a very nice original finish 12-S-265 empty cabinet for sale for $100. Since I only paid $15 for the radio originally it was worth $100 to have a nice original finish console cabinet. Now my buddy had to try and remember where my chassis and speaker were, since he had since retired and crammed everything into every nook and cranny of his two story garage. With the extraction of my chassis finally successful I began the first step of ordering the parts needed; capacitors, drive belts, and power resistors to rebuild the candohm.
Here are a few pictures of it on my chassis holder.... very dirty from years of storage but if you look carefully at the eye tube you'll see it is the elusive 6T5 that was only used in this year (1938) Zenith. Even if it still has life in it I'll probably replace it with a 6U5 or 6G5 and save it for special occasions.
This probably won't be a fast moving moving restore since I have some other competing projects I've been putting off. I am looking forward to digging into this chassis because the '38 Zeniths are one of my favorite chassis to restore, and this one doesn't seem too butchered up, so below is what I'll be working on:
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Well....these are not too bad.
9-S-262 is not that different, so...
Seized motorized drive.
Wash the tuning cap. I didn't. The radio isfine but while tuning it crackles alot.
6T5.....1) the 1M resistor is likely open (a popular problem). You could do the mod I did without opening the socket. 2) you could put the plate switch in and so save 6T5 life, making it glow for the aforementioned special occasions.
Candohm.....possible problems. Both my 11K sections were open.
The rest was easy....oh... 1st RF coil was open. The radio worked fine. Except SW wasn't sensitive.
They are a beautiful beasts, the Zeniths.
Very nice, John. At what probably was the last radio swap meet in the country before the stay at home's began (the WARCI meet March 15), I had a friend from the ARCI club bring me a 1938 Zenith 12 S chassis and matching speaker from a chairside set. I installed them in my 7S258 cabinet, replacing the 7S chassis and speaker. A perfect fit with no modifications (other than the tuning / motorized tuning knobs and bandswitch lever needing to be changed). It's the best of both worlds, a nice small console cabinet and 12 tube sound. So I just worked on one of these chassis myself. The nice thing about these is, except for the eye tube socket there is no crumbling wire and the chassis is nice and open (albeit a bit deep). I too have a 6T5 tube that has about 75% brightness left. I put a 6E5 in the set instead, like you saving the ultra rare 6T5.
Thanks guys. I think I recall you picking up that chassis Greg, glad it worked out for you!
Mike, I've done a couple of 9S chassis also so you're right, these are pretty similar. I'm hoping I don't have any coil issues, but just in case Terry lent me a spare chassis I can rob if needed.
I accidentally stumbled onto something on eBay that I think will make a dandy replacement candohm, a turret strip:
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Easy to mount the power resistors and connectors and you can just push out the unneeded turrets and cut to length. As soon as I saw those I decided to forgo terminal strips and just replace the whole candohm. Hopefully if it works as planned I'm going to replace the one in my 9-S-262 later when I change the belts and freshen up the electrolytics. I think it might look a little neater than terminal strips also.
https://www.ebay.com/itm/Turret-Strip-24...2749.l2649
GREAT idea, John! That looks ideal for candohm replacement. Thanks for the link and tip!
Are the posts through or blind?
How flexible is the board?
Mike, they are through holes and the board is fairly thick and not very flexible.
When you buy something like this on eBay sometimes it's a crap shoot on whether what you get is as pictured/described or even what you really wanted. This is one time I was not disappointed.
Building the new candohm is probably one of the first things I'll do so I'll take pictures and let everyone know how it turns out.
I was asking about the posts being through because I want to understand if this has to go on standoffs or not.
I don't think standoffs are necessary, but I was thinking about gluing a piece of fish paper on the back. In addition the two or three screws that will mount it to the chassis will also go through the fish paper insuring it can not dislodge.
Yeah...that would work...provided there is no or little protrusion.
I took the turret strip and power resistors and made my preliminary candohm replacement. I still have to cutoff the excess length, but the finished strip will be almost identical in length to the original candohm, which has at least two bad sections.
A few notes: I used 10 & 5 watt resistors per the recommendation of John Goller (K9UWA).
I decided to remove the unused turrets and found the easiest way was to use a 9/64 drill bit on the bottom and just lightly remove the small lip on the bottom of the turret.
To get two resistor leads to fit in the turret I had to gently enlarge them slightly with a 3/32 drill bit. There are ways around this but it would not be as neat. If you do this drill slowly and practice on a couple of the unused turrets because the first two I tried did not go well. As you can see I wound up with several extra turrets that I could glue back if needed, or if I found a similar piece of base material drill it and make a custom turret strip for a candohm replacement.
All-in-all I'm pleased with how it turned out and my connections to the candohm can just be wrapped around the applicable turret and soldered.
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Looks good John. I like how the strip came out and will use your idea in future radios when needed. I'm about out of radios that need restored and need to find some more.
OK, I've been working on the electrolytic capacitors which consist of seven capacitors in three different style enclosures.
The first is a wax cap under the chassis that contains three 10 MFD caps @25 volts. I replaced these with 50 volt caps. I cut the top of the cap into 4 sections with a utility knife so I could remove it without doing too much damage to the rolled lip of the capacitor:
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I was then presented with a very hard black tar. I heated it with my heat gun on low to prevent scorching the cardboard sleeve of the capacitor. Unfortunately the tar never got soft enough to pull out, but since the replacement caps are so small I just dug out a little cavity big enough for them:
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I set them in hot glue to hold them in place and then finished with brown hot glue, and have since trimmed off the excess heat shrink with an Xacto knife:
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The next electrolytic consisted of a 4 and 8 MFD mounted above the chassis. When I removed this capacitor it became apparent just how filthy this chassis is
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This dual section cap was just a cardboard tube that slid inside the Zenith orange can that mounted on the chassis:
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Presented with that same hard black tar I decided to take a different approach and stuck it in the freezer overnight. I then wrapped it in a shop towel and smacked it with a hammer (several times) and all the black tar eventually cracked and fell out. I did have to sink a drywall screw into the actual capacitor to yank it out:
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I put some filler in the tube to take up space, shot in some hot glue to anchor the capacitors in place. I then made another cardboard disk to keep from having to use so much glue as filler:
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Continued....
Continued: With the dummy cardboard top in place I filled it with hot glue and put the original cover in place and it's ready to be inserted back into the metal can:
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I then removed the final electrolytic that is a 12 and 20 MFD. Unfortunately it has that same hard black tar so into the freezer it goes
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I did take an hour or two to wipe off most of the dirt on the chassis, but I'll have to remove items to get everything as clean as it should be.