View Full Version : Found some old Zenith tube radio...


ESigma25
07-20-2018, 10:09 PM
My stepdad randomly surprised me with this old Zenith AM/FM tube radio that someone had thrown in the trash(!!!!).

https://i.imgur.com/1QCDYSj.jpg

Unfortunately for me it doesn't work. Is there anyone who could maybe help me identify this radio so I can work on trying to fix it?

Electronic M
07-20-2018, 11:19 PM
Don't know the model but that is one of their more common offerings...there was a more boxy cabinet version and plastic cabinet versions that I used to own.

It may still work fine on the original caps, but if not you can easily recap it without a schematic if you have changed the caps on another tube radio before.

Search eBay odds are one is for sale now and if the listing has a model number you can use that to search for service literature.

WISCOJIM
07-21-2018, 09:29 AM
http://radioatticarchives.com/radio.htm?radio=12716

https://www.radiomuseum.org/r/zenith_g730.html

.

ESigma25
07-21-2018, 07:29 PM
Yeah, I was dumb and didn't check the underside, says G730 plain as day...

I took the back off and noticed every single tube had managed to creep out of its socket, including the one in the metal sheath. I reseated all the tubes but it's still completely dead, it seems.

Titan1a
07-21-2018, 07:48 PM
Check and replace selenium rectifier and caps.

ESigma25
07-21-2018, 07:55 PM
Yeah, unfortunately that's way above my skill level. I guess I'll just hold onto it until I can find someone to repair it.

Electronic M
07-21-2018, 07:57 PM
If the heaters don't light either one is open (usually the higher voltage ones), or there's an open in the power cord or switch.

ESigma25
07-21-2018, 08:51 PM
So how exactly do you power up one of these radios that uses an interlock while having the back off?

WISCOJIM
07-21-2018, 08:53 PM
https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2499334.m570.l1313.TR1.TRC0.A0.H0.Xcheate r+cord.TRS0.TSS0&_nkw=cheater+cord&_sacat=73374

dieseljeep
07-21-2018, 09:55 PM
So how exactly do you power up one of these radios that uses an interlock while having the back off?

Remove the chassis from the cabinet and then you can reengage the interlock to the chassis.
The wooden cabinet models use the old style interlock connectors that Zenith used from the early days. Either that or make a test cord with insulated alligator clips and a standard power cord.
BTW, take notice how the speaker leads are connected before removing the chassis. Some of those wooden cabinet models used an electrostatic tweeter and the leads connect differently. :scratch2:

mr_rye89
07-22-2018, 12:02 PM
I have an early 60s plastic Zenith AM/FM clock radio that has a very similar chassis to yours, the main difference is mine has a silicon rectifier and all the coupling capacitors in it are ceramic disc types. I did see the one wax/paper capacitor on the back, so likely there's more inside. Those wax/paper caps should be considered bad at this point and should be replaced.

My Zenith was working as found, despite the original filter caps. It seems like I had to clean the power switch on it once though.

These sets are transformerless and a bit dangerous if you don't know what you're doing, as the chassis can become "hot" if it's plugged in backwards. And if it has a selenium rectifier that should be considered bad too. You might have to get the chassis out of the box to access it though