Vashio 2W DPSS Problem

[wondertwnz]

I have a pretty new 2W DPSS with the OEM Type power supply. I recently installed this in a projectors, tested and aligned the beam using a solid variable 5V supply to the Modulation input. This worked great,

Now when I hooked up to Pangolin and send the laser a modulated signal after about 30 seconds the laser shuts off. I have to power down the unit and power it back up and it returns.
I have found that I can drive the unit up to about 2.5V of modulated signal and it will run fine but more than that and it shuts down?

Any ideas. Could this be a ground reference problem? or possibly I need to isolate the laser head from the table?

Thanks
Larry

[Picasso]

could you be set to drive 5v-0v and not 0v-5v?

[logsquared]

I have a new 2 (months old) 2W vashio with the lab type power supply. I am having faults as well. Mine works under modulation (worst modulating DPSS I have ever owned) but if left to idle for awhile it sometimes goes into "error" and has to be powered off then on. Big PITA. Hope you don't mind me "piggybacking" your post Larry. Might be an issue with these 2W units?

[wondertwnz]

I have a new 2 (months old) 2W vashio with the lab type power supply. I am having faults as well. Mine works under modulation (worst modulating DPSS I have ever owned) but if left to idle for awhile it sometimes goes into "error" and has to be powered off then on. Big PITA. Hope you don't mind me "piggybacking" your post Larry. Might be an issue with these 2W units?

No problem on the piggyback.
Mine is only about a month old, Very strange. Does yours work fine when it is not modulated? Or do you know?

[wondertwnz]

could you be set to drive 5v-0v and not 0v-5v?

It would be at full output with Ov then I think?

[gottaluvlasers]

Hey guys-

I will look into this for you.

-Marc

[gottaluvlasers]

(double post, sorry)

Few ??'s-

1) can you try to hook up a non modulated 5V signal to the input? Any sort of 5V DC will suffice. does the problem reproduce?
2) If you switch laser to TTL- (or CW) does the lase emit at full power? (thus, eliminating the actual lasing as a problem).
3) Do either of you have a function generator? Something that can sweep a 0V-5V wave into the input?
4) Do either of you have an O scope to monitor the ouptuts of your DAC's just to make sure you are getting a proper signal to them? (im sure this isnt the problem, but doesnt hurt to test).
5) Can you measure the input impedance across the mod inputs for me? (power off, ohm it out).
6) If they are both lab type power supplys, do you have the current knob on the front? If so, can you turn the power of the system down to about half or even less. At this point, does the modulation problem still happen?

these lasers dont need to be isolated from chassis ground just an FYI.

-Marc

[logsquared]

1) can you try to hook up a non modulated 5V signal to the input? Any sort of 5V DC will suffice. does the problem reproduce?

Laser works great at 5V mod.

2) If you switch laser to TTL- (or CW) does the lase emit at full power? (thus, eliminating the actual lasing as a problem).

Yes

3) Do either of you have a function generator? Something that can sweep a 0V-5V wave into the input?

Yes

4) Do either of you have an O scope to monitor the ouptuts of your DAC's just to make sure you are getting a proper signal to them? (im sure this isnt the problem, but doesnt hurt to test).

Yes but have eliminated that by using a variable supply on the mod input

5) Can you measure the input impedance across the mod inputs for me? (power off, ohm it out).

2.1K

6) If they are both lab type power supplys, do you have the current knob on the front? If so, can you turn the power of the system down to about half or even less. At this point, does the modulation problem still happen?

I will have to get back with you on that one.


-Marc[/QUOTE]

[wondertwnz]

Same as Logsquared. Solid 5V supply works with no problems.
ttl- works with full output no problems.
I have an OEM supply so no Current knob.

[wondertwnz]

So I have been working with Frank on the problem for the last couple of days. We have tried quite a few modification to the driver but with no success. I can get a full power laser as long as I do not modulate the signal. I think I have a defective driver. Will hopefully get a replacement unit. Problem is I needed it for a show loading in on Tuesday so I do not know what I will do.
Will let you know if I learn anything else
Larry

[DZ]

If you are just doing beams and no graphics, you could always just turn the laser on and let your shutter handle blocking the beam. Would work fine for beams, but no at all if doing graphics.

[mccarrot]

Problem is I needed it for a show loading in on Tuesday so I do not know what I will do.
Will let you know if I learn anything else
Larry

In htis case you could make a colout palette where you never put out more than 2,5v out of the dac.

Al least you can do your show with half of the power then