Newwish (DX or other ) problem

[LarryQ]

Ok...So I'm pissed...tired, and ready for anything!

I bought a EL20 (extreme lasers 20 MW) from www.plans-kits.com.

I've had it for a few days..and have NEVER been able to get a real good beam out of it!

To make a long story short..I got it..tried Alk batts and was NOT impressed...
I've seen 5 Mw greenies do better!

I went to E2 lithiums, and got no better!!! (Uh Oh!!!)

I tried Pot modding and cutting the APC black lead thinking that the laser was CHOCKING itself off rather than lasing at 20 MW.

Well..one night...I found that all of a sudden..WOW Brite..big time...full 20 + Mw...
next day...Dim...5 Mw at best...



Anyway fast foward..it is a heat issue!

If I cool the unit down (place in the freezer or fridge for a min or two)..WOW she is BRITE!!!!!
Just as I had paid for when I bought a 20 MW unit over a 5 Mw!!

Let it sit in 90+ degree weather...and she goes DIM!!!!

I've repeated this experiment 5 times with all kinds of Batts....and can safely say it is HEAT related!!!

OK..so let's say that the IR diode is having a hard time getting rid of it's heat.
Let's also say that if I take this laser head apart..I will NEVER BE ABLE to get it aligned properly....

Other than throwing this laser in the trash..And saying Caveat Emptor... ( after Pot Modding they will NEVER take it back) What are my options to get this unit to remain COOL..or at least shed it's heat quickly enough to prevent it from turning into a 5 MW pointer (a Peltier is NOT a solution here !)!

Thanks..

LarryQ

 

[Hemlock_Mike]

Larry --

One word LN2 (liquid Nitrogen) !!!

After you pot modded it, how much current is the LD drawing ?? What was it before ?? There are lots of causes here. Did you try to turn it back to original current input ??

Mike

 

[LarryQ]

270 MA stock....

all the Pott modding never added a bit of brightness.(nor changed the current)...

Cool that unit off for a bit..and at 270 Ma..WOW....takes off like a raped ape!!!

Up, down with the POT, APC cut, APC connected.....

Heat (even ambient over 90') kills her!!!!

I've been playing with her now with a cut APC lead, and she is NICE!!!!!! (@40 Mw guess Big BRITE BEAM!!! Perfect for astronomy!))

But let her get warm, (warm ambient 90'air) and you have a <5Mw pointer!

I need a way to "Fill" the back of the diode chamber (when seen from the driver board) with something that will "Dry" , NOT CONDUCT electricity, yet conduct HEAT effeciently into the larger mass of the Brass head from the diode!

I was thinking Arctic silver Epoxy..but don't know if this will conduct electricity as well as heat!

Larry

 

[yew.sir-name]

i've been thinking about trying products like http://www.sculpt.com/catalog_98/adhesives/repoxy.htm as heat sinks, i've only used quicksteel for repairs, but it can be drilled, threaded and has loads of uses. like i said it's only an idea and i've not tried or tested it as a heat sink. i do know that when used to patch a blowing exhaust it gets really hot. but that's to be expected.

 

[SenKat]

Larry -

the majority of lasers in general use the case as either the positive or the negative contact point to complete the circuit.  Even if you did use an epoxy that did conduct electricity, you should be fine - as long as you keep it on the brass module part, on not on the circuiit board. since it is a greenie, it is more than likely case positive - you load the batteries in positive side up, yes ? the tail cap completes the circuit that the module starts when it comes into contact with the case. IF you isolate the module by NOT using conductive epoxy, you are screwed.

G !

 

[LarryQ]

Yes the case is Positive...and I forgot that fact...

THe problem is that I can not get the diode out....so whatever epoxy I use will have to be applied through the back through a small open area where you can see the back of the diode pressed into the body of the brass casement.

I guess the most important thing will be to make sure that no epoxy contacts the diode leads...

Uhhhhhh this is going to be tricky....I was hoping I could just FILL in the diode area with epoxy....

I'm off to the arctic silver site to check on the electrical properties of their thermal epoxy.

Actually, this method is the ONLY thing I can think of to help cool it...If this doesn't work, I have a Seasonal Laser...

LarryQ

 

[LarryQ]

Ok...I took it apart...again...and started really looking at how things are setup in there...

it liiks like the board is soldered to all three diode leads,glued to the brass housing, and that's it.

the diode appears to beretained by a screw in brass bushing rather than a pressed in fit.

I took some current readings, and found that with the APC connected, the draw was 270 Ma..and the Pot had no effect on the current draw at all.

I again clipped the black wire from the APC circuit, and draw went to 310Ma and still the pot had n effect on the current!

so...since 300Ma was to be the most I was hopiong to get out of this diode...310 Ma will have to do!

(at this point I don't care about life of the diode...she is 1 or two steps from the garbage anyway!)

In my testing, I found something very interesting!

THe diode are was BARELY WARMED, but the button was the warmest component on the board!!!!!

AhhhHAAAAAAAAA....

I may have a goofy switch!!!!!!

I don't know what I can do about this...and may just have to live with things the way they are.

My first greenie turns out to be a DUD...My luck sure is holding I see!

Larry

 

[Benm]

Since you're messing with it already, why not just solder a wire over the switch to short it out?

Obviously it will just light whenever you put the battery cap back on, but it would be a sure way to identify a faulty switch - that wouldn't be too hard to replace if its the only real problem.

 

[SenKat]

A good replacement switch can be had from the eject button on most cd/dvd roms or burners.... The switch is failry easy to desolder, and replace on the board with a tiny amount of epoxy, and solder

G !

 

[LarryQ]

A good replacement switch can be had from the eject button on most cd/dvd roms or burners....  The switch is failry easy to desolder, and replace on the board with a tiny amount of epoxy, and solder

G !

Ughhhhhh..

I wish I still had those 6 DVD burners that I harvested the DIODES from still laying around!!!!!!

Oh well...another reason to harvest another diode...heheheheh

LarryQ