General Electric Model 7-4305C Roll-Down Number Clock-Radio

General Electric Model 7-4305C Roll-Down Number Clock-Radio (front) - RF Cafe

General Electric model 7-4053C roll-down number clock radio doing useful service in its new home.

You know by now if you have visited RF Cafe a few times that I like to collect and restore vintage electronics and mechanical items that can be put to use - as opposed to just accumulating stuff and never using it for anything (although, admittedly, I do a bit of that as well). Since I don't do it for the collector's value, most items, if they are not already in good condition, get reworked until they look as new as possible - and work. Some "experts" would admonish me to leave the items with their original paint, varnish, metal and wood parts, etc., and never do anything that would destroy its authenticity. If I ever happen to acquire a Rembrandt or a Stradivarius, I'll be sure to heed the advice.

Part of RF Cafe's charter is to be a resource for people of like mind that are looking for historical information, restored examples, repair and renovation tips, etc., on vintage (aka retro) gear. Anywho [sic], for $20 on eBay I bought a like-new General Electric model 7-4305C roll-down (aka "flip-number") number clock-radio, date code 2051, made in Singapore. It was accurately listed as being in like-new condition, but with the display light not working. I replaced the neon bulb with a spare NE-2 bulb I had in my box of stuff. Now I can read the time numerals at night!

Note: The original resistors in the leads were replaced with a single 1/4-watt, 47 kΩ resistor, which allows the NE−2 neon bulb to glow at a comfortable level. Also, the metal foil originally wrapped around the neon bulb seemed to be causing it to fail since the replacement also burnt out after about a year. Now, a piece of plastic electrical tape holds the bulb in place, and it has been working finr for many years.

My motivation was to re-acquire the type of clock, radio, and alarm that was around when I was a kid, in the pre-electronic display era. A very similar model annoyed me awake each morning so that there would be no excuse for not arising in time to catch the school bus (my opinion of school in those days was similar to that of Calvin).

June 11, 2015 Update: See info on the AC synchronous motor used for the clock display.

October 2021 Update: The synchronous motor in my vintage General Electric Model 7-4305C Roll-Down Number Clock Radio began making grinding noises. An investigation showed it was the 3.6 rpm AC synchronous motor. It was tightly sealed, so I carefully drilled an 1/8" hole in the housing (being sure not to get metal debris inside), inserted a few drops of 3−in−1 oil and shook it around, then re-installed it, plugged it back in and voila - no more noise! (see photos below) BTW, if you can even find these motors on eBay, they cost more than an entire clock-radio. Fortunately, I found another 7-4305C at a yard sale so I have a spare.

Left side of GE model 7-4305C clock radio - RF Cafe

Left side of GE model 7-4305C clock radio.

Bottom of GE model 7-4305C clock radio showing ID sticker - RF Cafe

Bottom of GE model 7-4305C clock radio showing ID sticker.

- RF Cafe

Back of GE model 7-4305C clock radio.

Burned-out neon bulb - RF Cafe

Burned-out neon bulb.

GE model 7-4305C clock radio synchronous AC motor - RF Cafe

Synchronous AC motor was making grinding noise.

GE 7-4305C AC motor markings - RF Cafe

 Synchronous AC motor markings:

  S1   HNK    TOP    M3633
3.6   RPM    60-C    098

    Right side of GE model 7-4305C clock radio - RF Cafe

Right side of GE model 7-4305C clock radio.

General Electric Model 7-4305C Flip-Number Clock-Radio (top removed) - RF Cafe

Case top removed for servicing.

Neon Bulb Replacement (GE Model 7-4305C Clock-Radio) - RF Cafe

Detail of replaced neon bulb - RF Cafe

Detail of replaced neon bulb. I originally replaced the metal foil with new metal foil, then changed to plastic electrical tape when I determined that the metal foil was causing the neon bulb to fail.

Ah, the warm glow of a neon bulb! - RF Cafe

Ah, the warm glow of a neon bulb!

Hole drilled for oiling in GE model 7-4305C clock radio synchronous AC motor - RF Cafe

1/8" hole drilled in motor housing, then a few drops of 3−in−1 oil was squeezed in. Voila! No more noise!

See "How to Repair Your Electric Clock," in the December 1954 Popular Electronics magazine.

 

 

Posted October 29, 2021
(updated from original post on 12/10/2014)