Look for the thread on Otari bulb replacement. If you don't know a part number from a schematic you should be able to find a suitable replacement from an electronics part dealer, I'd expect it would be reasonably standard. If it is not soldered in place, and depending on where you live, you may be able to take one to an electronics parts store, if one exists in your city. You may be able to determine at least the voltage requirement with a multimeter.