The bulb is probably a PH302. You can verify this by comparing to the detailed info given at http://donsbulbs.com/cgi-bin/r/b.pl/ph302.html. Unfortunately that site states "Bulb is discontinued and I know of no substitutions at this time." A web search showed another place that may have a few in stock -- if so, snap them up: http://www.replacementlightbulbs.com...ofindmisc.html