When all else fails…

When all else fails…

The animated Dixie cannon watch was produced/rebadged by at least three watch brands — Nelsonic, Waltham and Armitron that I know of — but even so is very rare today.

The use of the Confederate Flag was probably less controversial in 1981 than it is today, but it’s more the animation than the subject matter that makes this watch so collectible.

So when you have one that refuses to work, it’s kind of annoying.

I’ve got a few (or more than a few) unique watches of this era, and manufacture, in my projects box where all methods to revive them have failed.This particular watch I even sent to two very clever repairers on the other side of the world, and they had no luck either. So it’s been languishing in the projects box for several years now, until recently.

Sometimes, when using a brand new battery, the display could be seen very very faintly. So in a last ditch effort I fired up the lab power supply and ran some volts through it to see if more voltage would help.

And, sure enough, it did.

About 2.6v was enough to have the display very clear and for the watch to run.

Trouble is, there’s no 2.6v battery.

There is, however, a 3v battery which is, remarkably, almost the same size as the 1.5v 371 battery that this watch takes.

It’s a CR927 and you probably won’t find one at your local battery retailer, although they are reasonably easy to find online.

I bought 10 at a bargain $1.88 and here’s the result. Very impressive, considering I had pretty much given up on it.

However all isn’t what it seems. Yes, it runs and, three of the buttons work as they are meant to — light, select/start/stop, and split/reset/alarm.

The rather important button, Mode, doesn’t.

This may be directly related to the amount of voltage now running through it, or it could just be part of the circuitry that caused it to stop working in the first place. In any case, it’s now a great display piece but doesn’t quite cut it as a functional timepiece any more.

Not that I’m bothered, it would be nice to have the animation and dixie melody working, but I’ve owned several of these and didn’t really use them much. It will look fine on display.

So what has happened to the watch to require it needing twice the usual voltage?

It’s almost certainly a capacitor issue.

Modules like this usually have one or two capacitors (called ‘upconverters’) which boost the 1.5v being delivered by the battery to a higher voltage required for the liquid crystal display to be visible.

It’s highly likely this is the component that has gone bad but it’s difficult to replace for two reasons — firstly, soldering watch circuitboards is tricky because they’re tiny (even worse is trying to resolder alarm coils which have wire bonds instead of metal contacts) and secondly because while capacitors of the right physical size are reasonably readily available, determining the value of the capacitor is hit and miss, mostly because there’s no service manuals for these kinds of watches. Even Seiko service manuals don’t list the values of their upconverter capacitors. So you could spend a long time soldering different caps in and out and may not end up with a working module.

About the only way to work it out would be to desolder a working module and get the capacitance reading from it, but since these are rare to come by in the first place (and wouldn’t necessarily give you the correct voltage capacitor to use) and no one is likely to want to potentially destroy a working watch just to provide a possible fix for another, the odds are not good for a permanent fix any time soon.

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