1941 Zenith 8A02 Console found - Videokarma.org TV - Video

TUD1 · #1 02-18-2015, 08:24 PM

I got this at the flea mall today for the princely sum of 75 big ones. I have no idea if it works, the cord is almost non existent. But I wouldn't have tried it anyway. I will be taking it to my local antique radio club this weekend and see what's going on with this thing. They may or may not remember me. The last time I was there was when I got my 1941 Philco 42-327 in September. I have never worked on a Zenith before, any tips or advice is very much appreciated.

TUD1 · #2 02-18-2015, 08:28 PM

Here's the back. For some reason, my i-Phone will only allow one picture per post.

Electronic M · #3 02-18-2015, 08:37 PM

The 6X5 tubes are prone to shorting and taking out the power transformer. Replace them with 1N4007 diodes.

Rotted rubber insulation on wires in this era of Zenith can be tedious to deal with.

TUD1 · #4 02-18-2015, 08:44 PM

I got this radio just in time for BirmingHAMfest 2015. They always have all sorts of tubes and testing equipment. I'll be sure to get the tube names for this radio and check for them at Hamfest.

rca2000 · #5 02-18-2015, 08:55 PM

Quote:

Originally Posted by Electronic M

The 6X5 tubes are prone to shorting and taking out the power transformer. Replace them with 1N4007 diodes.

Rotted rubber insulation on wires in this era of Zenith can be tedious to deal with.

And put a 1/8A. fast blow fuse in line with the power tranny HV secondary center tap. Perhaps a 1A. Slow blow fuse on the primary.

TUD1 · #6 02-18-2015, 10:18 PM

I have been informed that 8A02 is the chassis no. and 8S563 is the cabinet no.

Electronic M · #7 02-18-2015, 10:21 PM

Quote:

Originally Posted by TUD1

I got this radio just in time for BirmingHAMfest 2015. They always have all sorts of tubes and testing equipment. I'll be sure to get the tube names for this radio and check for them at Hamfest.

Do NOT replace the 6X5 power rectifier with ANOTHER TUBE, the 6X5 was a bad design and basically all of them (regardless of brand) are equally DANGEROUS to the power transformers (which are orders of magnitude more expensive and harder to find than the tube). Running one with a 6X5 is like running the set with a time bomb in it.

Just get 2 1N7007 diodes from your local Radio Shack or dealer of choice, remove the cathode and plate leads from the rectifier tube socket (leave the heater attached so it glows and looks original), add a terminal strip nearby under chassis, and attach those leads and the diodes (observing proper polarity).

TUD1 · #8 02-18-2015, 10:31 PM

I'm expeienced in toilets, lights, and vacuum cleaners. But I'm not very experienced in tube radios. I'll have to study the rectifier tube socket and all sorts of stuff before I can do that. Can you explain that just a little bit, please?

Can anyone tell me about small low power AM transmitters? The local AM station that I very much enjoyed is defunct, so now I have nothing to listen to except gospel and jabber-jabber. I hate both. Any ideas how I can play my own music over my antique radios without making the FCC mad?

***Kamakiri*** · #9 02-19-2015, 05:46 AM

They make a lot of styles, a friend of mine that had an AM-100 transmitter just bought one of these off ebay, says that it's a TON better than the one he had

http://www.ebay.com/itm/Talking-Hous...item5670c4da30

Electronic M · #10 02-19-2015, 12:55 PM

Quote:

Originally Posted by TUD1

I'm expeienced in toilets, lights, and vacuum cleaners. But I'm not very experienced in tube radios. I'll have to study the rectifier tube socket and all sorts of stuff before I can do that. Can you explain that just a little bit, please?

Can anyone tell me about small low power AM transmitters? The local AM station that I very much enjoyed is defunct, so now I have nothing to listen to except gospel and jabber-jabber. I hate both. Any ideas how I can play my own music over my antique radios without making the FCC mad?

Label and disconnect the leads on the socket pins K and P in the above diagram. K is the cathode. P are the Anodes (called plates in tube speak).
A 6X5 is 2 diodes in the same bulb with the cathodes connected together.

Above is the symbol for a 1n4007 diode the stripe on the part's body indicates the cathode end. It should not be too hard to figure out the connections from here.

It took me less than 3 minutes on google to find the pictures to make this simple to explain.

I happen to like talk radio when they have something interesting to discuss, but music is also important to enjoyment of such equipment.

DavGoodlin · #11 02-19-2015, 02:02 PM

TUD, I have that same Zenith and i got it off CL for $60 knowing the transformer was toast due to the 7Y4 tube,just as bad as a 6X5, of course.

It does not list that model number, just that chassis number - Very strange

Mine also has a 6K7 in place of the 1232 as an RF amp

I have a spare chassis (with a good trans) and speaker from a 8S359, also similar but with the evil 6X5.

Just haven't put the two together yet...

Electronic M · #12 02-19-2015, 02:30 PM

Quote:

Originally Posted by DavGoodlin

TUD, I have that same Zenith and i got it off CL for $60 knowing the transformer was toast due to the 7Y4 tube, just as bad as a 6X5, of course.

It does not list that model number, just that chassis number - Very strange

I have a spare chassis (with a good trans) and speaker from a 8S359, also similar but with the evil 6X5.

Just haven't put the two together yet...

TUD if your set uses the 7Y4 google "7Y4 tube data", and look for a PDF of a old tube manual listing of that tube containing a figure similar to the first figure in my last post....The set's schematic will also contain a similar diagram. If you don't have the schematic for your set check a site by the name of 'Nostalgia air' they have many schematics from the rider's manuals.

TUD1 · #13 02-19-2015, 03:55 PM

My Zenith does not make use of a 7Y4. Here is the schematic.

rca2000 · #14 02-19-2015, 04:08 PM

Do you all feel the same way about ALL of the indirectly heated rectifier tubes--like 6AX5, 6CA4, 6X4 , 5AZ4 ?

Electronic M · #15 02-19-2015, 04:33 PM

Quote:

Originally Posted by rca2000

Do you all feel the same way about ALL of the indirectly heated rectifier tubes--like 6AX5, 6CA4, 6X4 , 5AZ4 ?

No. Those later designs were greatly improved and MUCH less prone to the type of failures the 6X5 was infamous for (they learned from their mistakes). Heck if only it would not look like a complete hack job the 6X4 or 6CA4 would probably be decent replacements (with proper socket adaptation) for the 6X5.

Some of the LAST 6X5s supposedly were 6X4s or 6CA4s in an octal envelope, and were as safe as the rest of the later types, but if someone like me who has been doing this for over a decade has a hard time telling the difference, then advising a novice to do so would be a bad move... I don't want to give him advice that could lead to an expensive component (the power transformer) being ruined.