Tailcap may be the culprit?

Faulty driver.

Constant current means the current is held constant regardless of the input voltage (as long as the voltage is in a certain range). Your pointer is clearly not doing that. 3.6V is more than enough for any self-respecting linear driver to power a 1.9V load (the pump diode). I've had a couple greens that only need 2.2V.

For a direct injection laser, the input current is roughly linearly proportioned to the output power. That isn't the case with DPSS, and that extra 0.2A can make a lot of difference.

Cyparagon said:

Faulty driver.

Constant current means the current is held constant regardless of the input voltage (as long as the voltage is in a certain range). Your pointer is clearly not doing that. 3.6V is more than enough for any self-respecting linear driver to power a 1.9V load (the pump diode). I've had a couple greens that only need 2.2V.

For a direct injection laser, the input current is roughly linearly proportioned to the output power. That isn't the case with DPSS, and that extra 0.2A can make a lot of difference.

Click to expand...

Thank you for your diagnostic help Cyparagon. I will ask Ultimate Kaiser if he would be willing to fix this form since CNI can't help me. If he can't do you recommend any other member's that are comfortable working on PGL's?


Wanted to clarify something in the OP. when I wrote I used the laser 2 times for a total of 10 minutes run time I meant 2 sessions not I kept the laser on 5 min 2 times. I kept the run time below 2 min each on period. I was told by UK I should keep it even less than that and will from now on. I'd like to get as much life out of my dpss lasers as possible. That includes my 589nm Spartan. Thx

Cyp, this may be a very stupid question but when you said DPSS can deteriorate over time did you mean only when power is applied (as in from use). Pretty much most of what I have built just end up sitting in cases although I do test fire them every few months for no more than a few seconds.
Also, if I remember I'll check my 589nm Spartan and see what mine draws. I think it peaks at 82mW. Don't know if the information will really help though. Get that LPM fixed

"Don't run your pointers longer than 20 seconds or they burn up" is some weird boogeyman invented by LPF. Don't worry so much. Unless it's designed like crap, it'll run for 30 minutes just fine.

I'm not sure what the failure mechanism for DPSS is, exactly. I just know they can die with time, seemingly independent of their usage. Cheap chinese greens are notorious for this.

Hey guys little update for those interested. I re-soldered my wires and got my LPM back on line. I put these lasers on it tonight to confirm the depressing results from last spring.

561nm 30mW PGL-III-C- settled at 7mW, dropped as low as 2mW and briefly peaked at 12mW

on the bright side I metered my 50mW 589 spartan for the forst time and got these numbers;
589nm 50mW Spartan- settled out and stayed at 62mW, peaked at 104mW for about 5 seconds maybe more. Not just a random spike it stayed above 90mW for over a min.

Cyparagon said:

"Don't run your pointers longer than 20 seconds or they burn up" is some weird boogeyman invented by LPF. Don't worry so much. Unless it's designed like crap, it'll run for 30 minutes just fine.

I'm not sure what the failure mechanism for DPSS is, exactly. I just know they can die with time, seemingly independent of their usage. Cheap chinese greens are notorious for this.

Click to expand...

I tend to find these work pretty well when designed and aligned with care. I just got the laser tonight and after a brief alignment tweak of the lasing crystal, beam prep, and a light cleaning, its back up to power after a brief warm-up. the PGL-Cs have terrible heatsinking usually as the module is just floating in there. I usually say a couple minutes is the longest i'd let it run for a long time, but it is best to run it under a minute or so if possible. the module's stock recorded power draw is 1.7A for this laser, and I'm getting a consumption of 1.75A cold, and 1.73A after warmed up fully. interesting as most of the yellows I get tend to be pushing 1.8-2.2A depending, and they get very hot to the touch really fast. much hotter than is good for running a laser diode. the pump is in pretty good shape, but does have minor wear, but nothing notable. The main failures of DPSS are usually one of 4 things.

A) alignment change - either by abuse or thermal cycles making the crystals walk
B) dust, grime, foreign objects in the laser path
C) Excessive heat, causing early death/deterioration of the pump source, be it from no cooling, TEC failure, whatever. or in the case of the crystals, excessive power causing damage to the crystals (grey-tracking) or the mirrors. but this is mainly only a problem in very powerful systems. these handhelds don't come anywhere near this power level.
D) Driver failure/regulation problems - pretty self explanatory. again, heat being the main problem, but it can also be from poor design and regulation, or excessive power ripple/power surges, etc. but most of that is not a problem when battery driven.

Honestly, rebuilding these in custom hosts is likely a very good idea and could provide very long runtimes if they were well heat sinked or actively cooled with a TEC or something.

This seems to be good time to jump in on a question Ive been wary to ask. I have a good understanding and have read plently and have personaly experienced the instability of the 532nm greenie DPSS Like everyone I have a draw full of them. 3 or so months ago I gambled on 2 301 hosted 5mw 532nm. Yes they came in well over spec not metered but by guessing and expermenting. 1 of them lit matches by will instantly. So I boxed it and put it away quickly. The other took some time and focusing but lit matches but sporadilcly, and usually when first turned on with no warm up. I took out the 1st one that lit at will and now I cant get it to light a match with my life. Same batterys I always used (cheapies but well charged) and the laser was at warm comfortable room temp. I never over ran it or overheated it. To make this short is this DPSS deteriation? Why in my dresser draw and not on the shelves in the warhouse?

GSS said:

This seems to be good time to jump in on a question Ive been wary to ask. I have a good understanding and have read plently and have personaly experienced the instability of the 532nm greenie DPSS Like everyone I have a draw full of them. 3 or so months ago I gambled on 2 301 hosted 5mw 532nm. Yes they came in well over spec not metered but by guessing and expermenting. 1 of them lit matches by will instantly. So I boxed it and put it away quickly. The other took some time and focusing but lit matches but sporadilcly, and usually when first turned on with no warm up. I took out the 1st one that lit at will and now I cant get it to light a match with my life. Same batterys I always used (cheapies but well charged) and the laser was at warm comfortable room temp. I never over ran it or overheated it. To make this short is this DPSS deteriation? Why in my dresser draw and not on the shelves in the warhouse?

Click to expand...

The driver or Laser pump diode have probably died from overheating. Those 301 lasers are not built very well and have a habit of getting too hot causing all sorts of problems