I have a Timex Digital Heart Rate Monitor 585 (product code T5C351F5)m, which has the same Short AC Pad and battery +ve message. There is an arrowhead pointing to the pad. It's a raised metal platform - a bit different to some of the Ironman's mentioned above. Here is a pic....
Not worth repairing in my opinion. The trouble you are having finding a replacement crystal is indicative of the fact they are seen as disposable and simply not worth repair.
