What was the failure – no lasing, weak lasing, shorted diode, etc.?
(From: Robin.) The failure indicated by sudden drop in output power – from 1 W to approximately 200 to 250 mW. I just lit up the diode now as I’m typing this. No lens – straight at wall 1 cm by 9 cm red stripe with 3 black dots 1 mm in diameter randomly spread and a darker stripe centrally along the axis 3 mm thick. When I tried this a month or so ago the stripe was clean and the central strip was if anything brighter than the surrounding area. The flickering at switch on was: bright, dim, bright, dim, bright, off, over approx 3 seconds from what I can remember. I had previously tested the SMPS in the lab for an hour and it behaved itself. There are no switching spikes on the supply other than 45 mV p-p ripple at 200 kHz with no overshoot on the edges. It has a 1 ohm sense resistor so approximately 45 mA p-p ripple through diode. The only thing I have not done is to check the loop stability of the current sense feedback. It was not provoked by power on/off in the lab, but I must admit
