How to tune a CT6800HP for Blanking Use?

[300EVIL]

I have a CT6800HP with the 6580 Rev.D amp that Is setup for blanking. How would I go about tuning the amp to match the galvo in this situation? I'd say I'm fairly proficient at tuning galvos but I have no clue how or where to start on a blanking galvo. The mirror configuration does not allow me to just replace for X or Y and tune that way either. Suggestions?
Thanks!
Adam

[mixedgas]

This is JOB for SUPER BLANKING MAN!!!!

But since he's not around I guess I get drafted...

Start with a scope, tune for best square wave response.

Try not to use the offset pot on the amp for anything other then zeroing the amp. If you must add or subtract a DC offset from the blanking scanner, do it with software or a summing circuit before the amp. Other wise the quiescent current cooks the galvo amp somewhat, leading to early failure.

Ok, read here:

If you cant scan a image with it...


Then read here:

http://www.skywise711.com/lasers/scanner/scanner.html

Thanks to Skywise for hosting that for me...

Then read the blanking description in how to tune the ILDA test pattern

http://www.laserfx.com/Backstage.Las...Scanning1.html


The next step if you cant get it with ILDA is to replace the Y scanner with the blanking scanner and make a frame like this.

Add as many small triangles as you dare, until It gets right. Then make a frame with the touching arrows...

Ya going OLD Skool on us? Or copper vapor, or Melles, Or did you buy a used Eclipse??? If its the melles, just send it to me and I'll take good care of it...

Then thank LMR for not closing down his site, and BB for writing that..

Steve

[300EVIL]

Hey Steve!
Thanks a lot. I have scope, can do.

Ya going OLD Skool on us? Or did you buy a used Eclipse???

I wish! No, I'm just cleaning up an old set I got on a trade just to turn around and sell. I'd rather keep for a cool project with a large frame argon or SHG YAG but I need the money. I'll post some pics in a few.

[300EVIL]

Pics!

[-bart-]

Be sure to implement the blanking in such a way that the waste beam ends up in a proper beam dump.
Right now it looks like the waste beam ends upwards, under or above the retro.
I prefer the waste beam to go downwards in the first place, decreasing the chance it ends up in an eyeball.

[300EVIL]

Try not to use the offset pot on the amp for anything other then zeroing the amp. If you must add or subtract a DC offset from the blanking scanner, do it with software or a summing circuit before the amp. Other wise the quiescent current cooks the galvo amp somewhat, leading to early failure.

I think I'm having trouble with this part. When the galvo is at idle is should be seeing 0.0V at TP1 and TP2... Correct? If so, I'm not. It's -810mV. Would I then need to adjust R13 to correct it? When I try and tune the amp the transistor gets close to 130F with a good heatsink. I think this is too hot.

[300EVIL]

UPDATE

All good! A lot of variables to tweak but I think I got it working pretty damn well. I'll post some pics and or video soon.

[dsli_jon]

Hey Bart -

Be sure to implement the blanking in such a way that the waste beam ends up in a proper beam dump.
I prefer the waste beam to go downwards in the first place, decreasing the chance it ends up in an eyeball.

Depends which way you have the beam 'entering' the mount - ie, the GS mount 'example' below, shows this 'intended' left beam-input...



...Obviously, Adam must need to have his beam coming in from the 'right'...so, swinging the blanking 'paddle' that-far (with beam coming-in up-top, but using the retro, below...) would never work... ...at least, not for long..

He's got it 'right' - in both senses of the word - and I'm sure will watch his eyes / put a nice cover-plate on... he's got *some* 'xperience.... have you seen his 'signature'?

Nice job, Adam.. looking forward to pix...
peace..
j

[300EVIL]

Depends which way you have the beam 'entering' the mount

Exactly. I couldn't make this configuration waste beam up even if I wanted it to. Waste beam terminates slightly above the Y galvo back through the hole.

[-bart-]

My mistake, I had yet another configuration in mind. I'm used to having the retro bellow the galvos, no matter which way the entrybeam comes from. Either way, the beam never misses the retro, it 'misses' the X galvo.
Simply terminating a beam on anodized alu, especially when close the the galvos, always caused to much stray-light to my taste.