Several times there have been threads here about where to send out clocks for repair or replacement with quartz mechanism. I remember ballpark figures of $100 and complaints about long lead times. But I just did it myself, and found it was pretty easy.

Walmart sells a little plastic, square, black "Westclox" alarm clock for $6.90. Essentially, I took one of those and chopped it down to size so it would fit in the original instrument case. Everything you can see without looking behind the dash is original. Here is the "recipe" for doing this... somewhat primitive, but it works fine.

The Westclox movement is contained in a small plastic box attached to the back of the alarm clock face. Cut away the entire body of the clock except for the front, which you can use as a "chassis" to secure the movement to the case. You now have a flat plastic square with the movement screwed to it.

Snip the square "chassis" into a circular shape to fit in the original Smiths instrument case. Cut it to the same diameter as the Smiths clock face.

Peel off the Westclox paper face, and attach the Smiths face in its place using the original Smiths screws. You can just screw them straight into the plastic if you make an appropriate starter hole.

Bond 3 "spacers" to the inside of the case, in such a way that they'll keep the chassis centered, and parallel to the front of the instrument but set back a little. You can measure the setback distance by making marks on the inside of the case, with the original components in place. I fashioned my spacers from plastic rawl plugs, using a pen-knife. But you could also make them from wooden pencils, or whatever is at hand. You'll figure out the shape you need when you are actually looking at the parts!

Bond a nut to the back of the chassis with epoxy, and drill a hole in the back of the Smiths case that aligns with the nut. The hole is for the passage of a screw to pull the nut - and hence the chassis - back against the 3 spacers. You may want to scrounge in your "odds and ends" jars to find a nut with some kind of nice large bonding surface. Mine is a nut on a large flat base, and which came off a set of modular shelves...

Make a channel in the setting knob on the back of the Westclox movement, and drill another hole in the back of the case that aligns with it. You will use that hole for setting the time with a screwdriver.

Get a single AA battery holder at Radio Shack, solder its cables to the movement terminals, and pass the leads out through any of the existing holes in the case. You can attach the battery holder anywhere you like. However, I found it tucks under the mounting bracket so snugly, it didn't need any attachment whatsoever.

Unless you want to save the original Smiths movement (mine was totally kaput even to the naked eye) use some brute force to remove the two metal setting controls from the front of the Smiths movement. Drill appropriate holes in the new chassis and glue them in from the front -- they are now dummies.

Slightly ream out the holes in the original hands, and you should be able to attach them to the new movement without use of glue. The Westclox uses almost identical diameter holes, so the hands just press into place.

The result is 100% original from an aesthetics point of view. The only thing which will make the purists squirm, but which I could not resist, is attaching the Westclox second hand. It just gives me an extra kick to actually see that the thing works. But if you don't want a second hand, just chop it down to zero length, leaving the little disc in the center to look just like the original -- if you paint it white.

Oh, and one last thing... REMOVE the alarm buzzer! When the conversion is done you will have neither an alarm hand nor an on/off switch, and I discovered the hard way that mine was set to go off at 2:15 a.m.