You require a Multimeter.If you don't have one canadian tire stocks them for 25 bucks. As for a brand I recommend Panasonic, Don't get ripped off in wallymart for 5 or 8 bux. This is a example of where our shop orders some of its parts for electronic repair: http://www.digikey.ca/product-detail.../P189-ND/31939 that is the 2032 coilcell example.
Battery contacts are fragile, but also as preventive maitenace you can q-tip on a de-oxit to the battery and terminals. This prevents corrison and helps with contiunity between the battery and the battery contacts. I must warn do not spray it into the sealed unit or saturate the unit as it is conductive.
I use this brand at my work:
http://www.globalsemi.com/productdet...temno=GC191906
Just noticed that stuff was out of stock, can also use:
http://www.globalsemi.com/productdet...px?itemno=D5S6
Product is Called Deoxit D5, it come sin many forms.
On that note, anything that is not maitenance or a cleaning should be sent to a authorized repair center. These sealed units are never the same once opened, and sevice manuals are usually not openly available.