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Dodgy DX-30? Check the spring!

Benm

Benm

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I'm sorry to hear that it died so soon! I wonder if perhaps its an electrical defect rather than an optical or pump diode failure.

I've hooked the pump of the DX20 directly to a current source and ran it upwards of 350 mA for a bit... which is a good 80 mA above its current from the stock circuit. It suffered no ill effect.

In fact, i've crammed in my own driver that gives it 310 mA or so from alkalines, and i've played with it quite a bit now. Still works.
 





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photongeek

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Well, I'll try your spring mod, Ben. I'll also check for bad solder joints, you never know.
What kind of glue do they use to assemble these? Heat works?
 
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photongeek

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I also think it's an electrical or mechanical problem as opposed to the diode as it is still lasing albeit at a much lower output.
 
Benm

Benm

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photongeek said:
Well, I'll try your spring mod, Ben. I'll also check for bad solder joints, you never know.
What kind of glue do they use to assemble these? Heat works?
Click to expand...

Heat works for removing the cap, though it still takes so much force you really need to clamp it in a vice or something to remove it... it's too small to grab by hand with sufficient force.

As for the compount securing the circuit board to the laser assebly, heat from even a soldering iron seems to have no effect. I removed the solder from the LD pins and then rocked the circuit board loose from the compound... but this step is not required to fix the spring!

Btw, i noticed these boards are made with ROHS comlpiant components and solder. This makes it more difficult to create connections that are mechanically strong. I'd recommend resoldering the spring (or a wire to the casing from there) with old fashioned lead-based solder!
 
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photongeek

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MAN!!!!!!!!!! I have tried heat. Clamping in shaped wood blocks in a vise. Twisting and NOTHING will budge this cap. I used brute force and still nothing. Any advice Ben?
 
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photongeek

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I was finally able to remove the module but when hooked up to a 3 volt battery pack it appears it did not survive. That is a shame as I was very careful.
I am disappointed that it died so soon after so long a wait. Considering ALL of the problems associated with the DX line of lasers, I would NOT recommended anyone on this forum buying one, especially the higher end models. If your reason is low cost what exactly are you buying as these things are so prone to a quick demise? Do yourselves a big favor and save your money for a quality green such as a NOVA. I know I will.
 

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Benm

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Strange that it took that much effort to disassemble. I found the DX30 (same as yours) easier to get apart then the DX20 with the other board inside.

What's its condition now, does it do anything at all in terms of green, or not even the really dim dot you had before? Also, is it drawing any current from the batteries at all?
 
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photongeek

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Benm said:
Strange that it took that much effort to disassemble. I found the DX30 (same as yours) easier to get apart then the DX20 with the other board inside.

What's its condition now, does it do anything at all in terms of green, or not even the really dim dot you had before? Also, is it drawing any current from the batteries at all?
Click to expand...
Well Ben, before I disassembled it, the dot was about the same intensity as a cheap red. Now it's totally dead. The heat may have killed it. I'm not sure. I also wondered about the C5103 device. Is that a voltage regulator? I'll test it for current draw tomorrow but I think it is finished.
 
Benm

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It's a 2SC5103 transistor, nothing special.

Totally dead is hard to gauge on these things, when you feed the pump 150 mA, no light comes out at all... but feeding that same pump 300 mA resulted in a fairly well working pointer for me.
 
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photongeek

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Hey Ben:
I tested this thing for current and the circuit is only drawing 3 ma. The switch checks out fine. I also replaced the transistor (used a Radio Shack 276-2068) and still no luck so this thing is toast. Too bad as it was pretty cool while it lasted. That's it for DX lasers as far as I'm concerned. That's really too bad because on the surface, it looks like you're getting a superb bargain.
Have you had one of these operating long enough to determine it's not a lemon? Just wondering.
 
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philguy

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Idea that jumped to my mind (might have been discussed before):

Could one just change the Diode? Get another 1024 (or whatever) diode, and use that with the crystal assembly? Maybe get higher powers, or something more reliable.
 
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photongeek

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philguy said:
Idea that jumped to my mind (might have been discussed before):

Could one just change the Diode? Get another 1024 (or whatever) diode, and use that with the crystal assembly? Maybe get higher powers, or something more reliable.
Click to expand...
That's interesting Phil but we're still not even sure what's causing these lasers to fail. There sure isn't much on the board. Unless they're using really substandard components especially the tiny surface mount ones.
That would be a real coup if we could solve this but even if we knew the cause, they're a real BEAR to take apart without ruining them.
 
Benm

Benm

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Have you had one of these operating long enough to determine it's not a lemon? Just wondering.
Click to expand...

Not really, depends on when you call it a lemon though. My DX30 has about 2 or 3 hours total runtime (i guesstimate), and is fine. I'll let you know when it breaks ;)

About your dead pointer - perhaps it is some other failure in the driver, though it could as well be a blasted pump diode. If you are up for a little experiment, remove the existing driver, and run the diode directly from a current source. From my experience, it should light up at 200-250 mA, and run bright around 300.

I've installed a 300 mA driver in my sorta-dead DX20 and it does work again, just dims a bit when it heats up. I think i ran it for an hour or so like that in total, and it hasnt failed yet (though it probably will at some point).
 
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Ds1

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has anyone thought of hooking up the diode to a different driver? one with ttl would make it a nice laser effect diode ;)
 
Benm

Benm

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Thats perfectly feasible if you ask me. The whole pump + crystals + lens assemby seems to be a resonably sturdy unit that could be mounted in a laser effect scanner or something similar.

Driving it with ttl enable from another current driver would probably work, as i'm driving one myself without even using the feedback diode. One thing to keep in mind though is that these are quite sensitive to temperature, and light output could vary with duty cycle in such scenario.
 
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