This from wikipedia... (diode)
A standardized 1N-series numbering system was introduced in the US by EIA/JEDEC (Joint Electron Device Engineering Council) about 1960. Among the most popular in this series were: 1N34A/1N270 (Germanium signal), 1N914/1N4148 (Silicon signal), 1N4001-1N4007 (Silicon 1A power rectifier) and 1N54xx (Silicon 3A power rectifier)
Your Diode may be numbered 1N.... or perhaps BZ.... or possibly something else.
Examine the diode closely and look for any reference numbers (the broken diode may have friends of the same type and dimension close by it on the circuit board and these may provide a clue) Go to a hobby electronic shop and buy one for a few pennies. Be sure to put it in the right way round.
Good luck...
Peccavi, September 2009