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-   -   Found an early 1950s Zenith AM/FM Clock Radio at Goodwill today! (http://www.videokarma.org/showthread.php?t=268236)

Tubejunke 12-26-2016 09:28 AM

I have found that there are many things that can be used as gasket material and places like Home Depot are full of them, or better yet your garage. Tire patch stuff is a good idea. Inner tubes work good for lots of things. Hardware stores have a lot of stuff for weather stripping things like doors, air conditioners etc. Simple cardboard has bailed me out a time or two. I just sort of go into McGuyver (television show) mode when it comes to things like that.

And as to modern radio programming, I just wish that I could program a radio to play The Alice's Restaurant Masacree at wake up time. In four part harmony.....

Captainclock 12-26-2016 08:18 PM

Quote:

Originally Posted by Tubejunke (Post 3175604)
I have found that there are many things that can be used as gasket material and places like Home Depot are full of them, or better yet your garage. Tire patch stuff is a good idea. Inner tubes work good for lots of things. Hardware stores have a lot of stuff for weather stripping things like doors, air conditioners etc. Simple cardboard has bailed me out a time or two. I just sort of go into McGuyver (television show) mode when it comes to things like that.

And as to modern radio programming, I just wish that I could program a radio to play The Alice's Restaurant Masacree at wake up time. In four part harmony.....

Thanks, as to what I used as the gasket material for the clock mechanism's glass bezel I did end up using tire patch material and it works pretty well albeit with a little more of a gap between the cabinet and the dial glass than the original material had but it at least holds the dial glass in place so it doesn't cause any excessive wear on the clock dial. Now if I could only figure out a way to make the radium paint they used on the hands of the clock work again (its completely shot as it won't glow anymore not even when I use a full size Maglite flashlight shone on the dial for 2 minutes.)

Other than that the unit works great, and gets really good reception and I know some of the people on here said that this particular model didn't have AFC built in, and because of that its notorious for having drifting issues on the FM Band, but it seems like mine actually might be a later model that might actually have AFC built into it (albeit a very simple AFC Circuit) as I haven't had any issues with drifting on the FM Band on this radio (except for when I first got the unit and first fired it up and went to check the tubes and I found out that the 12AT7 tube that's in the radio was at one point in time replaced with a 12AU7A tube which was completely dead when I tested it and when I replaced the dead 12AU7A tube with a known good 12AT7 of extremely high quality the FM Band came back to life and never drifted since.) The reason why I'm saying that mine is more than likely a later model with at least a simple AFC built in is because there's a date rubber stamped to the radio chassis of October 1962, and as far as I know most AM/FM radios made by Zenith by that time had an AFC circuit of some sort built in to the radio whether it was the simple circuit mentioned in some of the earlier posts on here that was used in the 7 tube radios or if it was the more elaborate AFC Circuit that was utilized in the 8 Tube radios where the AFC Circuit was had its own tube powering it. Either way it seems to me that my radio may be one of the better versions of this particular clock radio model.

jr_tech 12-27-2016 08:09 PM

Perhaps this paint would work for the clock dial:

https://www.amazon.com/Paint-Aurora-...+in+dark+paint

not affiliated,
jr

dieseljeep 12-28-2016 10:41 AM

Quote:

Originally Posted by Captainclock (Post 3175630)
Thanks, as to what I used as the gasket material for the clock mechanism's glass bezel I did end up using tire patch material and it works pretty well albeit with a little more of a gap between the cabinet and the dial glass than the original material had but it at least holds the dial glass in place so it doesn't cause any excessive wear on the clock dial. Now if I could only figure out a way to make the radium paint they used on the hands of the clock work again (its completely shot as it won't glow anymore not even when I use a full size Maglite flashlight shone on the dial for 2 minutes.)

Other than that the unit works great, and gets really good reception and I know some of the people on here said that this particular model didn't have AFC built in, and because of that its notorious for having drifting issues on the FM Band, but it seems like mine actually might be a later model that might actually have AFC built into it (albeit a very simple AFC Circuit) as I haven't had any issues with drifting on the FM Band on this radio (except for when I first got the unit and first fired it up and went to check the tubes and I found out that the 12AT7 tube that's in the radio was at one point in time replaced with a 12AU7A tube which was completely dead when I tested it and when I replaced the dead 12AU7A tube with a known good 12AT7 of extremely high quality the FM Band came back to life and never drifted since.) The reason why I'm saying that mine is more than likely a later model with at least a simple AFC built in is because there's a date rubber stamped to the radio chassis of October 1962, and as far as I know most AM/FM radios made by Zenith by that time had an AFC circuit of some sort built in to the radio whether it was the simple circuit mentioned in some of the earlier posts on here that was used in the 7 tube radios or if it was the more elaborate AFC Circuit that was utilized in the 8 Tube radios where the AFC Circuit was had its own tube powering it. Either way it seems to me that my radio may be one of the better versions of this particular clock radio model.

The radio is from the mid 50's and doesn't have AFC. If it did, it would have an AFC position on the band switch. Using that higher quality 12AT7 probably minimizes the drift and the best thing you could have done. Whoever subbed that tube with a 12AU7, just wanted to get the radio playing, as its a poor sub.

Captainclock 12-29-2016 09:22 PM

Quote:

Originally Posted by jr_tech (Post 3175684)
Perhaps this paint would work for the clock dial:

https://www.amazon.com/Paint-Aurora-...+in+dark+paint

not affiliated,
jr

OK, that looks like some good stuff, so would I just paint this stuff over the existing paint? I'm wondering because it seems like if I were to chip off the old paint I would risk radium exposure and also I might not know where the original paint started and stopped.

Captainclock 12-29-2016 09:26 PM

Quote:

Originally Posted by dieseljeep (Post 3175722)
The radio is from the mid 50's and doesn't have AFC. If it did, it would have an AFC position on the band switch. Using that higher quality 12AT7 probably minimizes the drift and the best thing you could have done. Whoever subbed that tube with a 12AU7, just wanted to get the radio playing, as its a poor sub.

Yeah, I kind of figured as much, but wasn't sure. Anyways the 12AT7 tube I put into the radio was a Telefunken tube (which is of extremely high quality) which is probably why there's hardly any drifting of the FM dial, I have not been able to locate a service manual for this radio and because of that I have no idea what purpose each tube serves in the radio (the little tube placement guide on the bottom of the radio doesn't list what each tube does in the circuit for some reason.)

jr_tech 12-29-2016 11:04 PM

Quote:

Originally Posted by Captainclock (Post 3175842)
I have no idea what purpose each tube serves in the radio (the little tube placement guide on the bottom of the radio doesn't list what each tube does in the circuit for some reason.)

The 12AT7 is a double triode used as the oscillator and mixer.
In addition you likely have:

1-6BJ6 rf amplifier, 2-12BA6 if amplifiers, 1-12AU6 limiter, 1-19T8 fm discriminator/am detector/audio amplifier, 1-35C5 audio output and a selenium rectifier.

If it were my set, I would not bother with the luminous paint, or perhaps just paint over the paint on the tips of the hands...it would be very difficult to do the numbers.

jr

dieseljeep 12-30-2016 10:46 AM

Quote:

Originally Posted by Captainclock (Post 3175842)
Yeah, I kind of figured as much, but wasn't sure. Anyways the 12AT7 tube I put into the radio was a Telefunken tube (which is of extremely high quality) which is probably why there's hardly any drifting of the FM dial, I have not been able to locate a service manual for this radio and because of that I have no idea what purpose each tube serves in the radio (the little tube placement guide on the bottom of the radio doesn't list what each tube does in the circuit for some reason.)

Zenith made that same chassis for several years with just slight variations.
The first models that were changed is when they put the volume control on the left side.
The eight tube models were considerably different, AFC using a separate tube, tuned RF stage on both AM&FM, two stages of AM IF and larger speaker and two types of tweeters.
I have several models of all their AM-FM models, built through the years.

Electronic M 12-30-2016 11:34 AM

Mine has got a tone control on the side.

Captainclock 12-30-2016 09:36 PM

Quote:

Originally Posted by jr_tech (Post 3175851)
The 12AT7 is a double triode used as the oscillator and mixer.
In addition you likely have:

1-6BJ6 rf amplifier, 2-12BA6 if amplifiers, 1-12AU6 limiter, 1-19T8 fm discriminator/am detector/audio amplifier, 1-35C5 audio output and a selenium rectifier.

If it were my set, I would not bother with the luminous paint, or perhaps just paint over the paint on the tips of the hands...it would be very difficult to do the numbers.

jr

Its actually got two 6BJ6s, a 12BA6, a 12AU6, a 19T8, a 35C5 and a 12AT7 and then the Selenium Rectifier.

As far as repainting the clock goes, it only had paint on the hands and that was it, and that was what I was thinking of redoing, because of course painting the individual numbers would be a pain in the butt, also it wouldn't be original that way.

Captainclock 12-30-2016 09:43 PM

Quote:

Originally Posted by dieseljeep (Post 3175867)
Zenith made that same chassis for several years with just slight variations.
The first models that were changed is when they put the volume control on the left side.
The eight tube models were considerably different, AFC using a separate tube, tuned RF stage on both AM&FM, two stages of AM IF and larger speaker and two types of tweeters.
I have several models of all their AM-FM models, built through the years.

Mine does have an RF stage for both the AM and FM (according to what information I found on the internet at the Radio Museum website.) Anyways like I said unless it was just that the ink was smudged on the date stamp on the top of the radio chassis the date stamp dates the radio to 1962 (which could also be 1952 as well if the date is just smudged.) I guess that the radio having an RF stage would make it more sensitive/selective than a comparable radio without an RF stage, which would explain why the FM band on my clock radio just lights up with stations all over the place with just the built-in line antenna.


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