Note
Got the battery in my HRM replaced, less than 24 hours after it died at the end of yesterday's Park-O. Fastest turnaround time ever, but at the cost of driving to Waltham. He also changed the battery in my Timex watch. It was a kind he'd never seen before, which doesn't surprise me. It was a prototype that Timex sent out to members of the CMS Triathlon group a few (8 or so?) years back.
He's got a neat machine for testing the water-tightness of the seal. Instead of plunging the watch into water, he mounts it in a chamber, creates a partial vacuum, and measures how far the back of the watch case deflects based on the pressure difference between the chamber (near vacuum) and the inside of the watch (1 atmosphere, roughly). If there's no deflection, there's a leak. If there's a deflection, there's no leak.