29 Mar 2010, 08:54
Sometimes, if a watch sits for a long time [as in years], the mercury bead that normally does not stick to the longer part of the electrode starts to cling, or "wet", the metal, making for an unreliable 'break" part of the function. I have found that occasionally, if you give the watch a thorough shaking [for a minute or so, at 3 or 4 cycles per second], it will break the residue free, and return the switch to normal function [for a while, at least]. If not, the only fix is a switch swap; fortunately, the calculators use the same switch as the P4s, so a replacement should not be hard to find. Still, unless this is a major irritation for you, I'd be inclined to just let this go, unless you have the tools, parts, and skill to do the fix right. The calculator modules are complicated and relatively delicate, and it would be a shame to lose the whole watch over a minor problem. [And yes, I could do it, but it wouldn't be on my list of favorite repairs]. Try the "shake and bake" fix first, and if it doesn't improve, we'll go from there...