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

[Electronic M]

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...

[Findm-Keepm]

Originally Posted by Electronic M

The only thing that annoys me is that it's FM tuning drifts for ~20min after warmup.....

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..

[Electronic M]

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

Originally Posted by Findm-Keepm

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..

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.

[dieseljeep]

Originally Posted by Electronic M

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.

Christmas music from November 1st! 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!

[dieseljeep]

Originally Posted by Electronic M

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...

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.