First, the power dropped, rather suddenly, to about 60% of what it was. The EFR tube is only eight months or so old with not a lot of use. I checked alignment and fine tuned it but no help. So, I put a new RECI tube in and was pulsing it to check and adjust alignment. After about 10-12 pulses the RECI power supply starts beeping and says "Short circuit - analysis: high voltage." Where the high voltage line attaches to the tube the wire looked a bit weak but there were no signs (or sounds) of arcing anywhere. Just to be safe, I resoldered and reattached the high voltage line. After I started back on checking the alignment, again, after 10-12 pulses, the alarm went off again.
Might the power drop have been due to a bad PSU? I do have the original (cheap) PSU that came with the laser so I can put it back in and test, but it does not have any alarms or diagnostic output like the RECI PSU.
Any thoughts on the source of the problem would be appreciated. (Long ago I checked all the connections and tightened everything but have done so lately.)