Need 1941 Zenith advice - Videokarma.org TV - Video

jaymanaa · #1 03-12-2006, 11:30 AM

Howdy, What have I gotten myself into? My wife bought me a really nice Zenith floor radio for an anniversary gift a few years back. At that time my hobby was old Buicks, so knowing nothing about old radios I plugged it in and it played pretty good. Since then my hobby has changed to old tube audio stuff. Well, after some succesful recapping and resistor changing on some Fisher and HK stuff I remembered the old Zenith. Brought it down to the man cave for a power cord change and good cleaning (right). After pulling the chassis I have found that all wires that aren't cloth have little or no ins. left. I think I can change them one at a time, but what about all those orange, cardboard and wax capacitors? I guess my ? is where do I stop. I probably have enough Western Electric caps (I bought a huge lot in military packaging that seem ok) but do they really need to be replaced? I would greatly appreciate any and all advice on this project as the Old Zenith is a true survivor (the cabinet is near perfect) and deserves to live on for generations to come. Thank you kindly, Jay

Chad Hauris · #2 03-12-2006, 01:07 PM

I would replace all capacitors...there is probably at the most 20-25 paper caps. If you leave even one in, you run the risk of trouble from it so it is best to replace all. They should be replaced because 1. you will definitely get better performance even if the radio does work and 2. they can short out and damage resistors or coils.
I would not use NOS caps I would use brand new ones.
If there is old wiring with bad insulation where it is difficult to replace it, you can repair it by putting heat shrink tubing over it.
Also you should install a fuse in the power line. You can install an inline fuse holder and put it inside the chassis. 1 1/2 to 2 amps should do.
The thing is that if you really do this throroughly, replace all caps and replace or re-insulate all bad wiring it will work well and not need any work for many years.

maxm · #3 03-12-2006, 01:44 PM

I would check various online auction sites, before putting all those Western Electric caps in the Zenith, some people will pay a lot of money for those, allowing you to buy even more old audio gear...

jaymanaa · #4 03-12-2006, 01:48 PM

Thanks chad, Just got back from r-shak with colored heat shrink and lots of colored wire. I guess orange drops would be fine. Great idea about fuse. The only other problem I found was a tear in the field coil speaker cone. I think a little nail polish will do. Changing caps will make wire easier to access, any idea where a guy could find a schematic?

jaymanaa · #5 03-12-2006, 03:31 PM

Hi Maxm, I had that thought too. It's a big box full of caps and resistors in fancy sealed packaging from 50's and 60's. Some of the resistors are .5% tolerence etc. etc. I've hung onto it thinking some day of maybe building a single ended mono amp. Anyhow I have a whole new respect for antique radio, I've been all day changing 4 wires and 3 caps. Oh well at least I'm not trying to make a living working on them. What do you think about orange drops? Thanks Jay

Tom Bavis · #6 03-12-2006, 08:03 PM

Find a model number, and I'll find you a schematic. It's usually stamped on the back edge of the cabinet. Failing that, a chassis number, or as a last resort, list the tubes in it.

If this uses a 6X5 rectifier (or two), it's worth modifying to protect the power transformer if (when) one fails shorted. A line fuse is a start - better is a separate filament transformer for the 6X5s.

jaymanaa · #7 03-12-2006, 08:16 PM

Thanks Tom, I did find a schematic at a link I found surfing this forum. Haven't printed it out as printer is out of ink but it looks pretty good. The model as found in owners manual is 10s669 and chassis is 10B1. Looks to me like the rectifier is a 5Y4G. I got all the wires to the tone control panel and 3 caps changed today, and the dial light wires. The deep chassis makes things a little tougher than what I'm used to with the hi-fi stuff. Thanks and any suggestions are appreciated.

gary rabbitt · #8 04-01-2006, 08:59 PM

Hi Jay,
I have been lurking here for a while and finally registered.

If the online schematic is muddy or you can't read the writing on certain pages, let me know, and I can make a copy from my Rider's Manual for the Zenith. Sometimes the scans at nostalgiaair are hard to read, especially if the printing is very small.
I can echo the recommendation of replacing all the caps with new ones. Those NOS caps, even though unused can become leaky over time, so why risk damage on a nice set? THe NOS ones you may be able to sell online for those using the caps in low voltage applications.

Just a personal note, if I found a "virgin" chassis that had all the original caps still in place, I'd restuff them with the new components. Some may not care because it is the underside of a chassis. That's a personal choice. But if you don't restuff, perhaps save the old caps in a bag, in case another owner wants to restuff them at a later time.
Myself, I like to see the underside of a recapped radio that looks original.As I say, it's a personal thing. BTW, I do make a note to keep with the chassis that the caps are restuffed. Just so someone doesn't come in and this it hasn't been recapped.

Take care and good luck with the recap.
Gary Rabbitt

Chad Hauris · #9 04-02-2006, 01:06 AM

I personally like to see all the nice new caps on a repaired item...it looks like it has a new lease on life. Those old caps look very tired and worn to me! We do save the old ones in a box of old caps for historical preservation of what they looked like though.
We have had success using rubber cement to repair torn speaker cones.