I was wondering if anybody here can offer some insight into this...

It is OK for me to bring a tube clock radio up slowly on a Variac, or will this do some damage to the clock motor.
I'm just about to start work on a nice GE 577 set from 1955, and an wondering what to do about this, I've worked on many clock radios before, but I have always just turned them on, and would just like to know what everybody else thinks... :scratch2:

Thanks,
Max

The motor is synchronous (whereas I am not you know) which means it is in phase with 60 cycles AC mains. My guess is that it would either run faster/slower or not at all. If you are concerned about damaging it, why don't you short it out of the circuit, isolating it or completely removing it while bringing the radio up? I've never done that (using a variac) but having a 475 Musaphonic of that year and having looked in there it's just common stuff you could easily replace, Your set is even the same color as mine!

I vote for just replacing all caps before you use it...there are not that many caps in there. Usually the filter caps in the GE's are bad. Low voltage is not good for AC motors. Usually I just plug it in if it is from the 50's or later...have never had any trouble except a line bypass cap shorting in one set. I then will replace all the caps before I really use it as most of the time at least the electrolytics are really bad and replacing the paper caps yields better performance.

If it's really old stuff like from the 20's-40's all caps get replaced before it even gets plugged in as there is a higher likelyhood of shorts in this really old equipment.

When a short is suspected (like when a fuse has blown) I use a 60 watt light bulb in series with the power line to limit the current and help diagnose the short.

Sometimes in tube type electronic organs where there are hundreds of caps I have just left the old caps in, if it's my own equipment and it appears to be working OK. I'll use the ESR meter to help spot electrolytics which are going bad if I elect not to replace them all.

In many hundreds of devices I have worked on, from organs to amps, radios, projectors, etc. have never used the variac to slowly bring up voltage...I just follow the above guidelines. I know some people have got success with it, though.

OK, I guess I'll just power it up and see what happens...

PS: I agree about the bad caps in GE sets. I just repaired a 1940s GE AM/FM set and the AM radio portion of a GE TV/Radio I have, and in both the filters were really bad. I'd say that about 60% of the sets I worked on have had good filters that I didn't change, though I will proabably have to someday, I like to keep the sets as original as possible, even though they aren't really that valueable. Just from personal experience, Zenith sets have had the most reliable filters.

Thanks for the advice.
:)

The clock motor has such a high impedance that it won't draw significant current regardless of voltage, so it won't overheat. It probably won't start 'til 100V or so...

Took a look at the set tonight, and it is one of the most intersting clock raidos I have seen.

The set is a high quality set, with a big steel chassis that has a bottom plate, a phono input, the tubes have an intersting shield around them, which hides the intersting tube sockets which remind me of Zenith's "Service Saver" Chassis they used in their 60s TV sets. My favorite feature of the set is that the Clock's wires can be unplugged from the chassis, a great feature when trying to service the set, and you don't end pulling the wires out of the clock.
This is also the only clock radio I've seen with a date on the clock, a nice feature, when you want to know what day you are waking up to.

Looking under the chassis, this set was serviced at some point, the filters were replaced (which are now bad again), there are also two new Orange Drop caps in the set. It is a nice thought that somebody would actually think to service a little clock radio, something we would never seen today.

Zenith more often used the metal can electrolytics in table radios...the cardboard can like that used in your GE and like GE used as an OEM seems to allow the cap to degrade a lot more...I have seen some bad metal can electrolytics too, but they often appear to be more durable.

I would probably replace those black caps with color bands...they tend to be more apt to failure than other types of paper caps.

We found some replacement brand new electrolytics in cardboard cans that are made up to look like the one you have...we ordered a few at our shop but cannot remember who the vendor was.

I have a Zenith table top clock radio at home, vintage late 50s or very early 60s (the set has the old Conelrad markers on the radio dial). The clock runs and keeps good time, and I'm hoping to keep the clock part running for a while. Are there any lubrication points on the clock motor as there are with pure mechanical (wind-up) clocks? If so, what type of oil should I use, or is there a shop that would work on vintage electric clocks?

It's been a long time since I've had an electric clock of this vintage, though I don't remember those old electric clocks ever needing any service for years and years until they just stopped.




Thanks,
Joe

looks to be an easy fix.
replace the black/stripes and white caps in the lower left.
and the blue can at the top.
you wont hurt the motor with the variac since it is impedance protected.