With the movement removed, the circuit board off, and the wheel train bridge off, it was evident what stopped the watch. Aside from the rusty residue left on the moving parts there were also rust flakes. The stem threads deteriorated and with continued use, some flaked off and were attracted to the magnet of the rotor in the movement. These piled up around the pinion until it stopped the works. With the rotor cleaned up and after pegging the few exposed jewels, I reassembled it and it works. However, there is still a significant rusty residue on some components, and the pinion shafts in a couple locations are deteriorated. It can probably be cleaned up enough to run, but it’s accuracy will be questionable, so I ordered another movement. Tag Heuer uses an ETA 955.412, ETA’s high end quartz movement.
The new movement had a gold date wheel and a bad circuit board, so after swapping them out, the movement was ready. The wheel train in the new movement was cleaned, and the without rusty residue, it moves freely. The dial, hands, and case were cleaned, and the watch reassembled. The major losses were to the luminous features. The hand now have none and most was “cleaned” off the dial.