Re boarding a DXtrue 100

[IgorT]

hmm the heat changeing the brighness explains alot...
i did get green again! but i couldnt get it back after it probably cooled down.

The first crystal needs some heat, otherwise it is very inneficient, but with too much heat, the wavelength of the pump diode can change so much, that you get low efficiency again. The cooling needs to be just right and at the best spot.

I have actually lost efficiency, when i provided too much cooling to another green laser.

that sounds like a good idea. what would your add-on driver regulate.

Well the current of course.

The "drivers" in these cheap chinese lasers don't do anything more, than a resistor, capacitor and a diode would, even tho they have all the components on board, to achieve photo diode regulation.

This means, that as the batteries discharge and their voltage drops, the current through the diode also drops. Every time you turn the laser on, it is less bright than before.


With current regulation, the laser would get the same power every time you turn it on, untill the battery voltage drops too low. The best thing to do would be to replace the entire "driver" board with a proper driver - two AMC7135, maybe with a 20 Ohm bypass resistor, to drop the current to 600mA, or even without, if the laser can take 700mA. This way it could work down to 2.7V battery voltage, before you would lose regulation.


With an add-on driver, there would be additional losses in the original "driver", since it drops some voltage as well, but it would still be a good idea, if you don't want to take a laser appart. It would lose regulation at a slightly higher battery voltage, but would still be better, than no regulation at all.


The only reason, this would work with an AMC is, that these pump diodes have the positive potential at the base. So you just connect the negative potential through the AMC to the battery ground.


In both cases, it would then work from a single 10440 Li-Po cell. Using two would mean completelly wasting one of them, which is how i came up with the battery shaped add-on driver idea. It would basically drive the "driver". And since the "driver" doesn't really do anything, it would drive the diode through it.



Luckily my green lasers coincide with the 350mA current an AMC provides (700ma with two). For different currents, you could build a regular 317 driver, put it in place of the original one, and use two 10440 Li-Pos in the battery compartment. The end result would be the same - a much more stable laser.

 

[trueHOUSE]

;DI FIXED IT . I FIXED IT . IFIXED IT ;D im so happy : i dont know how . my dx 50 is now at full power NO DIMMING . last nighti decided to try to realign the crystal for last time . I put a silicone glue and the crystal after that , after 1 min realigning , now i have my perfect laser back to life

 

[IgorT]

That is great to hear!

I know how you feel. I can't wait to continue working on my laser either, now that it's bright again, and i found the perfect host.

It takes a lot of patience, but it is possible to fix these lasers or even make them better. Not necessarily brighter, but definatelly much more stable.