transistorized watches

[yankeedog]

Hey All,

             Just for grins I ordered a stellaris transistorized watch off fleabay. The watch, sold by the once great American retailer Sears and Roebuck has  a movement that was reportedly made by Seiko.It has what looks to be an oscillator controlled transistor switched balance. Any all all insight is appreciated.

[AndyHull]

1 hour ago, yankeedog said:

Hey All,

             Just for grins I ordered a stellaris transistorized watch off fleabay. The watch, sold by the once great American retailer Sears and Roebuck has  a movement that was reportedly made by Seiko.It has what looks to be an oscillator controlled transistor switched balance. Any all all insight is appreciated.

I suspect it will have.. a transistor, coil, a couple of capacitors, a couple of resistors, and not much else. Can you post a few pictures?

 

Is it like this example?
 

 

Edited May 5, 2019 by AndyHull

[yankeedog]

When it gets here.Once upon a time In one of my previous careers I was an electronics technician. I understand the principles involved in these little magic rocks called transistors. I will post a picture and pick your collective brains again .

[MrRoundel]

I have a couple Wittnauer electronics, an ESA 9150 and 9154. Literature is available in a step-by-step form for servicing them. I am not sure about the one you bought. I like them, but they do seem a bit temperamental. Maybe that's why I like them?

[Hamish]

I have worked on a few of these and in general they don't create too much difficulty for overhaul. The concept of operation is simple where the battery supplies power to an electronic circuit that outputs a pulse or wave form into a coil that drives the balance wheel via fixed coil on the board and permanent magnet on the wheel (some variations have a coil on the balance wheel). From there the wheel itself drives the movement. Interestingly this is the reverse of a normal mechanical watch 'power flow' where the balance wheel absorbs the power through the drive chain from the mainspring.

There are several variations to the above though, but the general principle applies even to tuning fork movements which have no balance wheel or course but the mechanical energy is derived from the fork, again into the movement drive chain. (take extra care servicing these...several very delicate parts)

In my experience you should find them relatively easy to work on and fault find. If the movement does not work then try to resolve between electrical or mechanical issues with the most common being open circuit coils, although I had a hard one to fix recently (Citizen Cosmotron) where the permanent magnet appeared to be damaged by the previous owner attempting to de-magnetise it. Luckily a spare was available. Check all electrical contacts and continuity and clean (Rodico does the job, or an ink rubber).

Many of these old movements can be tuned to keep excellent time and are well worth repair.....

 

Good luck.

[yankeedog]

To all.thanks for your time.