Stan wrote: >I attempted to head off chopper failure by replacing my 740B's neon lamps >with NE2H's (NE-2H was recommended by HP tech at now defunct Paramus,NJ >repair center) from Digikey (about 1993). Worked for about an hour. > >If anyone on this list has had recent, long term success, replacing the neon >lamps in HP419's, or HP740B's, please post the source for your lamps. Sorry, no recent experience. I bought my last bunch of NE-2s in the early '80s and rebuilt dozens of choppers and optoisolators with them, all with no problems. Sorry to hear that this simple and very useful device has lost some of its essential characteristics. Best regards, Charles