Tuesday, July 2, 2013

Leveriffic

A couple of weeks back we had a power surge at our house.  Nothing seemed to be affected with the exception of both of our alarm clocks in our bedroom.  The odd thing was, on one the radio worked, but would not display time, the other would display time, but the radio didn't work.

Coincidentally, while out garage saling with my wife the following Saturday, she spied this 1959 RCA Victor Levermatic AM Radio/Alarm Clock.  It's a model C1E.




The plastic housing was fairly discolored as was the face.



The seller said the clock worked, but the radio didn't play. For a $1, I thought it was cool enough just as a display piece.

There are two levers on the radio (hence the name). The one on the left of the clockface controls a timer. This can be set up to 60 minutes to allow you to fall asleep to music. The lever on the right controls the on/off and auto/alarm. The far right dial is the tuner and the middle dial controls volume.

When I tested it at home, I was happily surprised to find that the radio worked after the tubes warmed up. However, there was a fairly loud howl over the music.  This is typically caused by a leaky capacitor.  The capacitors used years ago were made of paper and wax which understandably break down with heat and time (and let me tell you, those tubes get mighty warm).

I disassembled the radio and removed the plastic housing.  I was pleased to discover what I thought was discoloration from sun and heat was actually just surface grime, most likely from a heavy smoker.

When you take apart something like this, pictures are extremely important.  I try to take them from every angle and show every part.  You never know what's going to be important to see once you start reassembling.





In order to get the circuit board out, I had to disconnect the power to the clock, transformer and the antenna leads.

Clock power leads


Antenna leads



I disconnected the transformer power at the circuit board (from left to right, the blue, red and brown wires)


I cleaned out the inside and started examining the circuit board.  I identified one multi-capacitor (the large yellow cardboard canister in the above picture).  These have 2 differing capacitances and 1 common post.  Fortunately, the capacitances were printed on the side. One was 50 MFD (Micro-farad), the other 30 MFD.  I also identified 3 other wax/paper capacitors.  2 were .047 MFD, the other .015 MFD.



I found the modern replacement capacitors on Antique Electronics Supply. They didn't have a 50/30 MFD canister capacitor available, but they did have a 50/50 one.  This is acceptable as a larger capacitance (within reason) will give similar results.  The same goes for the voltage ratings -- more is okay, less is not. The total cost was about $10.  When de-soldering old eletronics, I recommend a medium duty soldering iron (75 watt).  The solder used back then is heavier and requires a higher heat to melt.  Also, remove one component at a time.  It's easy to lose track of what goes where.  The replacement canister capacitor's prongs didn't line up with the old holes, so I had to solder solid wire extensions onto them and soldered the wire to the circuit board.  Here are the old capacitors after I removed them.
 

The circuit board with the new capacitors minus the tubes.


Not my cleanest soldering job, but it did the trick.

The final reassembled board.


When everything was reassembled, wonder of wonders, it all worked.  And no more hum over the sound.  It's as clear as a bell.   The reception wasn't great and required my hand to be placed solidly on top of the housing to get a clear signal, so I soldered 2 extension wires onto the antenna leads and threaded them out the back of the radio.  This greatly improved reception. It's now on my nightstand and has been functioning as my main alarm clock. 


Below are the schematics and parts list for this 1959 RCA Victor Model C1-E Radio/Alarm Clock.  They proved to be very helpful during this project.





3 comments:

FrankO said...

man, that's a night-and-day transformation. what did you use to clean the plastic facing? anything special?

Tom said...

Simple soap and water. I wondered about that As Seen on TV plastic polish that clears fogged plastic. But most of it was just smoke residue from years of falling asleep smoking and listening to the radio.

FrankO said...

i have some plastic polish for cleaning up snow globes. it really is a series of cleaners with super mild abrasives that you use in order of lessening grittiness, and it really does seem to help, for what it's worth.

Related Posts Plugin for WordPress, Blogger...