19 Feb 2017, 01:13
There could be any one of a thousand things wrong. Leaking batteries can cause all manner of random and catastrophic damage...and there's always the possibility of static electric charge, which can kill any of the 1500 or so transistors in the clock chip, causing varying degrees of loss-of-function (none of which, being internal to the integrated circuit, are repairable). Broken reed switches, bad quartz crystals, and defective displays can be fixed, but, for the most part, while some problems CAN be resolved, the vast majority of them can't. We are now nearly 45 years out on the longevity-curve, and these watches are now developing issues that Time Computer never had to deal with, because they never saw a watch more than 5 1/2 years old.
The one bright spot is that ones that ARE still working, will continue to do so for many more years..well-assembled with exceptionally-good parts, lightly and carefully worn, well-maintained. The design lifetime of these was 100 years (an ambitious goal, for a fledgling company using technology with a limited track-record). A few will make it (sadly, most will not); but one day, there will be no more original working Pulsars. Modern modules are already taking up some of the slack of the attrition, but it will always be a collectors' dream to have the real thing...