trouble with pot mod for silver leadlight

[joniverson]

Hi,

Recently purchased a silver GLP-105? from Vital Spirit Ebay source with intent to increase power by the pot mod. I removed the oval button, but with this laser I was unable to gain access to the pot. I could see it, but it was quite angled away from the oval aperture. I then decided to pry the laser open to gain better access. I read the various tips here in the forum and other sources suggesting to use a knife or similar to work the top out of the cylindrical body, but this was no easy task! After marring and nicking up the top, I was finally able to separate the laser module from the body. The pot on this laser just didn't have a flathead like most normal pots and I had to adjust the far edge. I adjusted it until the laser got brighter and then quickly went out, then backed off to the point just before the laser extinguished. However, when I press the button, the beam is bright and then gets dimmer after a few seconds. I've had this happen on two lasers I've tried to pot mod. Any ideas why the power is dropping and is there a fix?

All in all, I'd say this particular silver GLP is different than earlier ones from the same source, and it appears to be harder to modify. Of course, I'm taking a guess here, but the instructions I've read concerning mods are not as easily performed on this laser.

Appreciate, in advance, any advice or tips.

Thanks,
Jon

 

[Wincet]

I've had that happen to a leadlight of mine and it was permanently damaged in my case. For me backing off to increasing it had no more effect and the laser eventually died. Hopefully, that is not the case for your laser so I'd advise you to take another opinion before giving up.

 

[joniverson]

When I ordered these, I ordered them in pairs so I have two of them. The silver one I talked about above finally died as I think it was caused by the screwdriver touching both the case and the pot. I was still never able to get the brightest output to stay at that without dropping though. The other Leadlight appears to be a black one made in '05. It seems to be a lot closer to what has been discussed in this forum, but in all honesty, I'm finished trying to get more power out of these. Out of the three I modded, one is burned out now as I said and the other two start off bright and get dimmer with pot turning making no more difference. I could just bypass the driver board and input voltage directly. I do that with my red diodes and get a good output out of them. Not sure it's worth the risk for the price.

I had debated ordering just a plain DX in higher powers and for the price, I went ahead and ordered the 30 mW one (the only higher powered one that seems to be in stock at the moment, although I think the 50 mW keychain might be in stock too but avoided it due to no reviews) . Even if it doesn't have an IR filter, one can easily be added from an old webcam or even this burned out leadlight I have.

Unfortunately, it seems to me like the current Leadlights have been made much harder to modify so maybe best to avoid unless an older one can be obtained (and this appears likely from the older black model I obtained).


Jon

 

[joniverson]

A little update here: I was able to successfully apply the pot mod to the black Leadlight that was marked made in '05. I still had to remove the module from the housing, but for some reason this was MUCH easier than with the silver model and very little prying to remove it. There was also no IC on the bottom of the circuit board as there was with the silver model, so my guess is the older circuit without regulation. Much brighter now, the brightness isn't dropping after a few seconds, and I can easily see the beam in a well lit room.

Jon

 

[Lew Fong]

Jon,

The VS Leadlights have automatic power control or APC circuits in them that make power adjustment rather complicated. Plus, as you have discovered, it's not all that easy to do the modifications without damaging the units. But that isn't a function of the year of manufacture, really, since even the older units required special handling techniques to be successful. The modifications sound easy when described on the forums, but in practice call for a highly skilled hand at working with microcircuits, soldering, fine mechanics, etc. It is possible to perform a really nice tune-up on the old or the new, and restore them to like-new appearance, but it takes a lot of practice. Many folks here at CPF have gotten pretty good at it, at the cost usually of a shoebox full of "experience". (I must have a hundred dead cowboys at least). So hang in there...there's virtually nothing new under the sun, and everything you need to know can be found on these forums, somewhere.

Best of Luck,

Lew

 

[joniverson]

Hi Lew,

I haven't intended really to go beyond the pot mod on the Leadlight clones I have. The trouble I had, as mentioned in another thread, was that the pots themselves were covered in a green colored glue which, once broken, seemed to interfere with adjustment and somewhat with output. My solution for the worst case was to remove the pot completely and bring the pot traces outside of the laser to either an external pot or small value resistor. So far though, I haven't needed to insert a resistor at all as the laser seems at nearly full output as when I first did the mod except for a slight dimming issue that I am trying to work on now.

I don't know what the output is of these clones, but both will "dent" the foam of the casing in which they are normally stored. No burning, just a small dent in the black foam if I leave the beam there for a few seconds.


I have since added IR cut filters to both of the clones. I had to experiment a little to find a cheap IR filter alternative as new IR filters can be pricey, but a Logitech webcam's IR filter seems to offer the best response at the present time. IR is not completely extinguished, but reduced enough that I can't detect the IR reflections with an IR sensitive camera. This small step should allow the green protective goggles I have to be a lot more effective.

Thanks for the encouragement,
Jon

 

[Lew Fong]

Curious about your "clones", Jon: No IR filters? Where did you get them? All the lasers I ever bought from Vital Spirit had filters installed. But they are genuine Leadlight, not clones....so I'm confused. Did your VS units not have filters?

 

[joniverson]

Hi Lew,

The clones were obtained from an Ebay source called Novaphone. They did not have IR filters upon arrival. The IR filters I added were about the best I was able to find without spending a lot of time and money. They are out of a Logitech Express webcam. Easiest to remove, square, and fit into the laser cap with a dab of epoxy. I tried several filters, but this was the one that blocked the most IR based on my crude testing (ie looking for laser IR reflections off the wall with an IR sensitive camera). (Note for anyone that tries this webcam- there are different logitechs even for the same model so some IR filters won't be removable).

Interestingly, both of these clones, once the IR filters were added, were able to pop black balloons at close distance <2" from a "cold" start last evening. Once they had been used for a while, the balloons wouldn't pop.

BTW, I do have a pair of greens from Vital Spirit also. One burned out when the screwdriver touched the housing during the pot mod and the other modded, but not nearly as bright as the clones. It did have the IR filter as you indicated.

Jon