The CYMA Sonomatic

[Bill241]

I’ve spent a bit of time learning about alarm clocks- particularly the higher end Swiss ones- as an inexpensive way of learning about complications.

Here’s my CYMA Sonomatic: a fairly rare alarm clock introduced in 1958. The ‘Elite’ model featured here was priced at 15 Guineas (£15 15 0 in British pre decimal days, I believe) at the time. About a week’s wages for a skilled factory worker at the time.

It’s an 8 day movement which is quite unique as the alarm itself is also an 8 day one, overcoming the limitation of all other mechanical alarms which will completely run down its mainspring unless manually stopped. On the Sonomatic, the alarm will sound for a few seconds every 12 hours and then automatically shut off (thus, no good for heavy sleepers!) It should sound up to 19 times on one wind. 

There’s very little on the ‘net about these so to assist others working on this calibre, I’ve posted some images of the strip down intended to show the movement and particularly the unique automatic alarm shut off mechanism.  Basically it is a cam with a small pin that makes a single revolution and then acts against the disconnect lever to stop the alarm. 

Within an hour or so, the hour wheel pushes the disconnect lever down a little further, eliminating the resistance against the cam pin, and so the spring loaded cam springs forward a few degrees and is ready for the next alarm cycle. That is, if it’s set up correctly.

It took me a while to figure out the set up as when I rebuilt it, the cam pin would briefly depress the disconnect lever then carry on revolving so the alarm would not shut off. The trick is to adjust the disconnect lever sideways to ensure just enough resistance to stop the cam. The disconnect lever is quite sophisticated but the two screws holding it in place can be accessed easily from the dial side (top marks for design!)  and then adjusted. With quite a bit of trisl and error, it’s now working perfectly. 
 

 

[oldhippy]

I remember repairing this type of clock. Well made as well. Someone has had a go at the bush for the hammer as it looks as if someone has used a punch on it, it is also filthy dirty. 

[Bill241]

The photos were taken during disassembly. Like all of these clocks I’ve looked at, filthy dirty. I doubt it’s been serviced in 30 years. The oil was so old it had turned green! The third wheel pivots were so gummed up the clock barely ran at all. 

I agree about the build quality and design. The movement is almost completely silent unlike the loud tick of lower quality clocks. 

Edited November 29, 2023 by Bill241

[watchweasol]

Hi. Along with the Swiza movements these were good quality for alarm clocks. It will clean up very well. Use Windles clock oil on the rebuild is the best for clocks.

[Nucejoe]

3 hours ago, Bill241 said:

The movement is almost completely silent unlike the loud tick of lower quality clocks. 

I find the loud tic of clocks, relaxing. 

[Bill241]

9 hours ago, watchweasol said:

Hi. Along with the Swiza movements these were good quality for alarm clocks. It will clean up very well. Use Windles clock oil on the rebuild is the best for clocks.

I haven’t worked on a Swiza yet- some inventive designs, certainly, but I’m not a fan of pin levers or the alarm/movement running off a single spring. I prefer CYMA, Looping (particularly the cal. 50-55) and Imhof from the 50s-70s period as they are more like pocket watches than clocks. They are usually very cheap to buy- I recently bought the smaller version of the Sonomatic, with calendar, for £6.

I avoid the prewar alarm clocks and 8 day timepieces having read the Horological Journal articles on the dangers of radium dials! 

For lubrication I tend to use HP1300, 9020 and 941 for the escape wheel/pallets with a thick grease like DX or 8300 on the barrel arbor pivots. I’ll get some Windles though as I do occasionally work on larger clocks.