My dad's Zenith - been in the family since new - Videokarma.org TV - Video

TUD1 · #1 11-07-2015, 11:45 AM

My great aunt and uncle bought this brand new in 1940. Then, in the early 50's they traded with my grandmother and grandfather, and in 1968, my dad got it. By then, it didn't work anymore, and it hasn't played since. I grew up with this in the house, and I'm determined to revive it. At the very least, it needs a new cord, new electrolytics, and the dual 6X5's need to be dealt with.

Electronic M · #2 11-07-2015, 12:30 PM

I have a similar set.

I got it for $20 at the MARK Extravaganza meet some years back.....Mine is a model designed for 25Hz power, and surprisingly it worked GREAT on it's original parts....I still recapped it though.

TUD1 · #3 11-07-2015, 02:35 PM

So do I. A 1940 Zenith 8S563. Mine works, but it needs a new dial belt. It has a 6X5, so I don't use it much. I need to get some 1N4007's in there, but I'm still not sure how. I want to keep the filament voltage so I can keep a tube in there and it be lit, but not operational.

David Roper · #4 11-07-2015, 03:41 PM

Just fuse the plate leads with #47 bulbs. If the 6X5 should heater-cathode short, the bulbs will expire immediately, much too quickly to put your transformer in danger. I have yet to experience a 6X5 failure myself and have not a tiny number of sets that use it, both radio and TV. One of the TVs uses it as a damper! So taking the bulb-fuse precaution is definitely worthwhile, but don't be scared of the things.

Captainclock · #5 11-07-2015, 05:15 PM

Quote:

Originally Posted by TUD1

So do I. A 1940 Zenith 8S563. Mine works, but it needs a new dial belt. It has a 6X5, so I don't use it much. I need to get some 1N4007's in there, but I'm still not sure how. I want to keep the filament voltage so I can keep a tube in there and it be lit, but not operational.

From what I've been told by some on here is that the 6X5GTs are safe to use but not the 6X5Gs or the 6X5s (the ones with the metal jacket), so if you have a 6X5GT in your radio you should be safe and shouldn't have to worry about any sort of shortouts.

TUD1 · #6 11-07-2015, 05:49 PM

Okay thanks. The 11S474 has 1 6X5G and 1 6X5GT. My 8S563 has a 6X5GT and it has not given me any trouble. I would like to know the secret with the diodes, though. I've heard that you connect the diodes to 1 and 3, 5 and 7. But I'm really not sure. I'd like to put the original Zenith 6X5G in my 8S563 for looks.

David Roper · #7 11-07-2015, 06:08 PM

There are three distinctly different variations of 6X5GT construction and there's pretty much a consensus of how reliable they are from most to least. But the least reliable construction lived happily in your radio for almost 30 years. It's your radio, but if you care about its originality, my suggestion is the least invasive fix.

Electronic M · #8 11-07-2015, 06:17 PM

Quote:

Originally Posted by TUD1

Okay thanks. The 11S474 has 1 6X5G and 1 6X5GT. My 8S563 has a 6X5GT and it has not given me any trouble. I would like to know the secret with the diodes, though. I've heard that you connect the diodes to 1 and 3, 5 and 7. But I'm really not sure. I'd like to put the original Zenith 6X5G in my 8S563 for looks.

I prefer to remove the plate and cathode leads and use a terminal strip for the diodes. Google "6X5 tube data" and search "diode" on wikipedia. There should be more than enough data there for you to figure it out....I was able to do mine based on that info.

David Roper · #9 11-08-2015, 01:41 PM

One more thing: The #47 trick was Zenith's own recommendation, straight from the horse's mouth so to speak. ISTR that no radio so modified has ever been known to burn up a(nother) power transformer. Keeping the 6X5 in the radio as intended also keeps the voltages correct, as a voltage drop through the tube would have been factored into the design. A diode has no voltage drop.

TUD1 · #10 11-10-2015, 07:45 PM

But not without one casualty. When I took the volume, tuning, and band select switch off, the cheap pot metal linkage that connects to the chassis got hung up on the lever and broke. Will J-B weld fix this? I can't find another on Revovated Radios or anywhere.

TUD1 · #11 11-10-2015, 07:48 PM

Here is the chassis after 3 hours of cleaning. I vacuumed the cabinet out, used contact cleaner on all the switches and tube sockets, cleaned the tubes, and cleaned the chassis. This radio has all the original tubes except for one RCA 6X5GT/G. Even the 6U5 eye tube is original!

Electronic M · #12 11-11-2015, 11:29 AM

Quote:

Originally Posted by TUD1

But not without one casualty. When I took the volume, tuning, and band select switch off, the cheap pot metal linkage that connects to the chassis got hung up on the lever and broke. Will J-B weld fix this? I can't find another on Revovated Radios or anywhere.

JB weld might work. What I would do is epoxy the break back to gether and while doing that also epoxy some flat pieces of sheet metal over the broad flat areas on either side of the break to add extra strength (I think I repaired one like that, but it's been a long time).

I'm sure a good machinist could make you a new one. You might be able cast a new one out of aluminum or similar if you have experience or know someone who does that kind of thing (the inner shaft hole would still need to be machined).

These parts are VERY prone to breakage when removing the chassis if due care is not taken. IIRC there is supposed to be something like a C clip on the tuning shaft to keep those from yanking off with the band switch lever, but those are often missing......

dieseljeep · #13 11-11-2015, 12:39 PM

Quote:

Originally Posted by TUD1

But not without one casualty. When I took the volume, tuning, and band select switch off, the cheap pot metal linkage that connects to the chassis got hung up on the lever and broke. Will J-B weld fix this? I can't find another on Revovated Radios or anywhere.

I have the eight tube model and I can't get the band selector lever off. I don't want to break either.

Does your 11S474 have 10 or 11 tubes. They kept the same model number, even though some models had only 10 tubes. The 10 tube model used a 6Q7G and is chassis #1005.

TUD1 · #14 11-11-2015, 04:06 PM

It has eleven tubes. Thank you for the advice, Electronic M.

Electronic M · #15 11-11-2015, 05:09 PM

Quote:

Originally Posted by TUD1

It has eleven tubes. Thank you for the advice, Electronic M.

You are welcome.

Quote:

Originally Posted by dieseljeep

I have the eight tube model and I can't get the band selector lever off. I don't want to break either.

Have you tried penetrating oil on it? PB Blaster has worked wonders on rusted bolts on my car....If it can do that it should be able to help with that radio....Assuming the pot-metal has not swollen over the years.