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
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.
Bottom of GE model 7-4305C clock radio showing ID sticker.
Back of GE model 7-4305C clock radio.
Burned-out neon bulb.
Synchronous AC motor was making grinding noise.
Synchronous AC motor markings:
S1 HNK TOP
3.6 RPM 60-C 098
Right side of GE model 7-4305C clock radio.
Case top removed for servicing.
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!
1/8" hole drilled in motor housing, then a few drops of 3−in−1
oil was squeezed in. Voila! No more noise!
Posted October 29, 2021
(updated from original post on 12/10/2014)