Paul C. Buff, Inc. Technical Forum

i bought my 640 einstein lights, and i used it two times, suddenly one of them stop flashing. the bulb flash is ok and the counter for each flash i click works

If it has only been on two shoots, then it is possible for the problem to be a bad flash tube, though it could be something deeper. If you have another E640, you can try swapping tubes, allowing at least 5 minutes after the units have been unplugged, and being careful when swapping tubes to avoid breakage.

If you only have one flash unit, or it only fired two pops, then you should contact customer service to arrange for warranty service.