Laser-Export LCM-DTL-374QT 355nm Odd Behavior

[MarioMaster]

I've had this laser sitting around for a while, it had always performed fine so I never bothered to extensively test it. A bit ago I went to trade it to Junktronix so I powered it up and metered it. Was doing perfectly fine, peaking around 50mW at ~5KHz pulse rate.

So I send it off. Then I get a string of PMs saying how the laser isn't performing as specced after the first run. He sends it back.

I powered it up and metered it - again it was behaving as normal, nice clean power increase with pulse frequency peaking at ~50mW. Then as I let it run it suddenly drops in power and stability hovering in the 15-20mW area, just as he described in the PMs.

I've poked and prodded at just about everything with no change so it doesn't seem to be an alignment or electrical contact issue. Also the PSU is supposed to output 2.5v at target pulse energy and another output should be +5v when the pulse energy is >10uJ. The first output is hovering at like 0.6v the other is basically 0v.

Any idea what's going on and what I could try to test to see if it's operating properly?

[MarioMaster]

I've done two more test runs today, it has been running fine. Averaging 38-40mW or so for 10+ minutes no problem at around 6HKz pulse frequency.

[shrad]

a tired capacitor maybe? but I don't know how you could verify that