Found an early 1950s Zenith AM/FM Clock Radio at Goodwill today!
 

Hello everyone today I found an early 1950s vintage Zenith AM/FM Clock Radio Model J733 at Goodwill where I work for $6 and some change after I used my loyalty dollars on it (it was originally $20.) Anyways it still works without humming and everything the only thing that doesn't work is the clock mechanism which contains a Telechron movement and I happen to have a spare Telechron rotor laying around that still works that I can install in it to make it work again. Anyways I'm planning on using it as my primary alarm clock to get me up for work, because its just so cool. Also the bakelite cabinet is crack free but does need a good polishing, any suggestions as to what to use to polish the cabinet with?
Pictures of the unit posted below.

I've got the all blue version of that and have been using it as my morning alarm for several months.

The only thing that annoys me is that it's FM tuning drifts for ~20min after warmup, and the only strong stations (which it won't drift out of tune on) that play good music have gone over to Christmas stuff for the season, and as much as a bit of festive music is nice, if I had to wake up every morning to it I'd be found hanging from the ceiling fan one morning or my radio would get destroyed...

If this model had AFC that feature would be worth it's weight in gold to me.

I've considered AM, but I don't want to wake to talk, and I suspect the one music station is too weak to survive drift...

I too have one of these "bugeye" Zeniths.

Replace the ceramics in the oscillator and FM Converter section with NP0(C0G)ceramic discs for lower drift. Surprisingly, silver micas fail to prevent the drift....

IIRC, it was hard finding all the pF values at one vendor..

Compare the circuitry in the newer seven tube Zenith AM-FM radios that have AFC. I know the seven tube models have a simpler AFC circuit, than the eight tube models, that have a separate tube for AFC. It's worth a look. :scratch2:

I was thinking about 'borrowing' an AFC circuit for another model.

Interesting I may have to try that.

ATM my radio is way at the bottom of a massive list of projects....I may mod it in time for next year's Christmas music switch though. :tongue:

Christmas music from November 1st! :thumbsdn: The day after Thanksgiving day was early enough.
The stations and their Arbitron ratings. Many times around the first of the new year there is a format change. I hope, it's a change for the better! :yes:

The question is if they will move towards the TOC or towards the same modern crap they've been moving towards (some of it was decent, but a LOT just ain't my thing)....One thing I wish they would do is can their morning hosts...About a week in to using them I renamed their "Murphy & Meg in the morning" music+idiots chatting show to "Murphy and Meg are ANNOYING"....It seems like there is more yaking then music.

it occurs to me there is a big alarm controlled power outlet on the back...Maybe I should just set it to run a audio player of some format so I can program my own wake up music.

Looks like 95.7 is sitting on top of the heap... I would not expect major changes.

http://ratings.radio-online.com/cgi-bin/rol.exe/arb043

The shift over time is likely to be toward newer tunes, to stay centered in whatever their target demographic is.

jr

How did this thread go from talking about a 1950s Zenith Clock radio to discussion about radio stations and what they do and do not air?

That's the way many of the threads work out around here.
It's been a little dry, regarding new topics. It's a good thing that there is a few members that are sharing their experiences with their projects. :thmbsp:

Well I'm having a bit of a problem with my Ol' Zenith it seems that (and I already mentioned this when I initially posted this thread) my radio's clock mechanism isn't working, tried swapping out the rotor thinking that maybe the original rotor may have seized up over the years (which is quite common for old Telechron movements) but even my known good telechron rotor didn't work on this clock and the transformer for powering up the rotor is still good as I can still hear it humming away when its plugged in, the only other thing I can think of is that the movement itself is seized up and that it needs to be oiled up but the clock is a pain in the butt to get apart because you have to actually remove the whole radio chassis itself out of the cabinet in order to get access to the clock movement and I already had it apart once tonight and I don't want to take it apart again right now, (at least not tonight) anyways do you have any ideas as to what could be wrong with the clock mechanism on my radio? Like I said the radio part works flawlessly yet, its the clock part I'm having issues with.

Try turning the time-set knob. If it's real hard to turn, the clock movement is all gummed up.
The coil and laminations are known as the "field". Remove the field and rotor assembly and see if the pinion gear is turning. The output speed is 3.6 RPM.

I was finally able to get the clock to work, it turned out it was a bad rotor after all and the known good rotor I had wasn't installed correctly which is why it wasn't working with the known good rotor installed. Now I have a new problem, broken tuning string going from the tuning knob to the main tuning capacitor pulley, I replaced the original tuning string with a new one, but now I can't get the tuning knob to turn the tuning capacitor pulley, which would in turn rotate the pointer pulley, and I've tried stringing it every which way possible from what I remember it being strung up but no dice, what it does is that it will turn it toward the lower end of the tuning dial but it won't tune it toward the top of the dial because the tuning knob pulley just keeps rotating continuously within the tuning string and not actually turn the tuning string, and I don't have access to the service manual for this radio so I can see the stringing diagram for the tuner on this radio. It acts almost as if there isn't enough tension on the tuning knob but if I wrapped the tuning string anymore times around the tuning knob pulley I wouldn't have enough string to go around the tuning capacitor pulley, and its already wrapped around the tuning knob 4 times already (and 4 times is usually the maximum amount of times that I've seen tuning string wrapped around tuning knob pulleys on these old radios, because usually 3 times is the norm.)

UPDATE: finally got the tuner fixed, apparently 5 was the magic number as far as the number of times I had to go around the tuning knob pulley before going back to the main tuning capacitor pulley, which is odd because I've never seen a tuner stringing that required you to go around the tuning knob 5 times before. anyways, when I got the radio put back together I tested it out and the tuner was drifting really badly and also it would barely pick up any stations on the FM band except the really strong local stations.
So I took the radio back apart and checked all of the tubes in my tube tester and all of the tubes checked out fine except for a Raytheon 12AU7A tube that was obviously a replacement/substitute for the original 12AT7 tube in the radio, that tube was completely dead (no heater/filament glow whatsoever), so I replaced the tube with a correct 12AT7 tube that was a Telefunken branded tube and then put a new shield over the tube as the shield they had over it previously was just a cardboard tube that was painted silver, and then put the radio back together reattached the built-in antenna and fired up the radio and sure enough it was working perfectly again as far as reception goes, no drifting, and it was picking up more stations than before on the FM dial. Also I saw a date stamp on the radio chassis that dated the radio to 1962 (which I'm not sure if that's correct or not or if maybe the ink smudged just enough to make a 5 look like a 6) but either way it seems that I have this radio up and running again.

OK so what should I use to replace the old dry-rotted rubber gasket material that went between the clock dial glass and the cabinet? I was thinking of using that rubber tire patch material that comes in 2" strips for patching holes in tires temporarily, but want your guys' opinion as well, as far as what I should use.

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.

Perhaps this paint would work for the clock dial:

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

not affiliated,
jr

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.

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.

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.)

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

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 has got a tone control on the side.

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.

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.