02 Jun 2010, 14:34
You'll have to remove the module from the watch, and power it using a 3V supply (2xAA batteries in a battery holder with alligator clips attached is good for this).
Then, wave a magnet near the reed switch. If nothing, then short the 2 ends of the reed switch with a piece of wire. If still nothing, then it's not the reed swicth.
Normally if it's the oscillator circuit, then single digits may appear. They may change to different digits, or nothing at all, as power is disconnected and then re-applied. The QC is part of the oscillator circuit, so changing it may help. It won't necessarily help, since other parts of the oscillator circuit may have failed (which are generally not repairable).
Rgds,
Andrew.