1942 zenith and other radio projects.

[brando_husky]

Just picked up this 1942 zenith 10s669 radio. I picked it up for a good price based on how lovely and original the radio is.

I'm not going to touch the cabinet other than cleaning and waxing a bit. The real restoration is to pull the chassis and do a complete rewire, recap and new resistors.

These era of zenith use a poor rubber coating on the wires. After a few decades the rubber cracked and fell apart from vibration. Causing a very high safety issue


The store claimed it "worked" but my roommate and I are much smarter to try and turn it on before we replace at the very least the caps and damaged wires.

will install an AM transmitter so I can play anything from my phone over the radio.


As you can see the cat wanted to inspect the radio for me lol

 

[brando_husky]

Another two radios of ours.

A 1930 Philco model 20 cathedral radio we cleaned up and restored. It is almost completely original.

Also a 1936 Philco radio we are rewiring and capping at the moment. Got new grill cloth and such.

 

[dartman]

Zenith made some of the best radios back in the day, and many makers used lousy rubber insulation for years after that radio was made.
We have a much newer National/Panasonic that the insulation for the dial lights is falling off.
I have a few old military and civilian short wave and broadcast radios around here and several are smaller Zenith. I also have a plastic Zenith table radio with the extra rf stage that I used to shoot an skip with. It would pull stuff in lesser radios couldn't hear and was probably made somewhere in the late fifties to mid sixties I think.
For its size it sounded great too.
I think it still works though the case has fallen apart after being baked all those years.
I used to tweak all the IF and RF cans and things to keep it at peak receive performance and dial alignment.

 

[kenkart]

Zenith

Always had the very best FM..The Armstrong system.

 

[cb123]

Well, I bought this one just the other day and the pack rat came for free!

 

[brando_husky]

Dropped the chassis this evening.

Couple areas of concern. Several wires are still original and badly cracking. Most are a little stiff. Lots of paper capacitors that need replaced. Couple electrolytic capacitors on top that I have to cut and bypass with modern caps since they don't make reproductions.

Tubes are very dirty but probably work just fine. Most are zenith stamped. One delco and one GE.

The transformer will be replaced. Lots of original wires going up into the body. Not going to mess with it. Best to have replaced for safety.

The original belts were dried out and brittle. Have some on order.

Other than that and an unknown chassis stain around a tube, it will polish up beautifully.

 

[tolivac]

Zenith radio chassis-Had a chassis just like that one shown-it didn't have the case.Someone gave it to me while I was in college-It did work-had to connect it to an external speaker.The lower frequency Armstrong band was abandoned in favor of the present VHF FM band.Beleive it was interference issues.If the radio was built in 1942-surprized Zenith was building consumer product radios at all at that time.During those war years the high quality rubber was being used for the "war efforts" so lower quality stuff was used in consumer products.Later after college gave the chassis to someone else that I knew who collected old radios.He had the case!I didn't need it at that time.If I could have saved all the stuff I gave away or sold-would need a warehouse to hold it.Beautiful radio!!! You may have to put a back panel on it to keep your cat out of it if you want to play the radio when you are finished fixing it up.Just remember doing minor things in mine.Someone before me replaced the cables in the chassis.Have known three people that collect old radios-the hobby is fascinating--but EXPENSIVE!!!I gave my Zenith chassis to one of them.I was nice in those days-now I would SELL it to them!

 

[cb123]

I bet you the dog bones are still 10 to 30% in tolerance which is pretty good. Ceramic disks would be a great replacement for your papers, they're really not that noisy at all and they just about last a life time are two. Be careful with that metal tube if its been replaced for a glass one, on account, pin one should be grounded to glass which it isn't no more -- its been turned to metal! Remember my friend electricity is a wild, caged animal just dying to find its way to ground!

 

[tolivac]

Yes,some metal power tubes like 6v6,6F6,6L6 have the metal "shell" of the tube connected to the screen circuit-and these tubes run HOT!!!!!!More than enough to take off skin-and with the screen connection--HOT in more ways than one-shut off the power and let the set cool down before replacing!!!In one 6L6 amp I used to have the paint was burned off the 6L6 output tubes-came from a Seeburg jukebox.The glass tubes are safer-and believe it or not have a higher plate dissipation.

 

[brando_husky]

Wow guys! Thanks for the great info!

Not taking any chances with the caps. Going ahead and replacing them all. Might as well ignore any slight tolerance drifts and ensure all new proper sized caps with modern safety design be put in place.

I noticed that metal tube and thought it was quite interesting. I've got friends with tube testers and several shops in town with tubes available. Shouldn't be hard to get it checked up on but I am sure it's still fine. Tubes never seem to really go bad very easily

 

[brando_husky]

Cleaned up the chassis a bit. Not too bad

 

[cb123]

Polypropylene and Mylar caps would also be fine for replacing any kind of paper cap. You can be pretty close to the MFD, but the working voltage you need to be at or above -- Same for your electrolytics.

 

[brando_husky]

Yep! I've found a great source of caps at radiodaze. My roommate is good at reading them and soldering so I leave that to him. I do the touch ups and cabinet work. Some wiring here and there. Not my forte.

 

[brando_husky]

One thing I will need is a new transformer. That one there has some very bad looking wiring entering it. Wouldn't hurt to set it up with a fresh built box for safety

 

[cb123]

Just heat shrink the wire and unplug the rectifier tube and slowly power it up on your variac and see if your transformer gets hot. That will we tell you at least half the story.

 

[dartman]

Tube testers

I have a early 50's I-77b two piece military tube tester, a suitcase Sencore mu-50 mid 60's one, a early thirties wood cased one and a few Beltron CRT rejuvenaters that were handy when I was doing TV repair as a money making hobby. I have boxes of tubes going back to the 20's when they looked like light bulbs, had two numbers and 4 or 5 pins. I collected them from the early 70's on whenever I found any at garage sales and elsewhere cheap. There are tube substitution manuals out there that will help you find close or perfect replacements from different numbers, some are actually better than the original type.

 

[brando_husky]

That's an interesting idea with the heat shrink. Might do that on a few of the tougher wires. Anything with a cap I'll most likely pull and replace.

Would anyone know if this era would have a cloth power cable or rubber? The old tattered unoriginal cord and plug need replacement. Baaaaadly

 

[dartman]

My guess would be cloth but oldest one I have as far as Zenith is probably early to mid fifties and is rubber. Heat shrink would work great if you don't care what it looks like. I use it on my old Dart when the crimp connection jobs were getting dirty and it was heating up. Cut it out, stripped the ends back, soldered them together after sliding some heat shrink close, then slid it over and heated it tight. That wire has been fine since and doesn't heat up. That thing looks so nice and clean I'd put it on your isolation transformer too and see how it does. Some of the tube TVs I worked on the main power transformers ran super hot and looked cooked and always were fine. Many caps that are bad will bulge or leak or look cooked. I have a late 20s regenerative radio that I just don't have enough early tubes to get it running. The filaments light up and nothing caught fire when I powered it up years ago to see if anything tried to work. I spose a isolation transformer would have been a good idea and might still get one if I find a deal on one. I don't check for that kind of stuff like I used to seeing how I don't repair stuff actively anymore except my own stuff.

 

[brando_husky]

I think it will be most easiest to replace the cracked wiring. Trying to slide some heat shrink tubes over the wiring sounds difficult