Grounds for murder?

[Mr.Coffee]

Update, round 2:

So I thought about the situation last night, and I figured that since both the galvos are turning, that it is probably just a tuning issue. when I got into work today, I cracked open that pot and found that I'd set the replacement off by about 5 kohms or so. I adjusted it and presto! a recognizable image. the only problem is that at wide scan angles, the x amp seems to collapse and I have to reset the scanners to get it back (perhaps that polyswitch is doing it).
I have pics of what it looks like now, as well as what it looks like after the scanner collapses. on the third pic (I can't remember what the name of the test pattern is called), when I adjust the scan rate down to 8k, the image looks great, the corners are nice and crisp, and everything lines up. at 30 k, the image causes the scanners to collapse after about a minute or so. (needless to say, I try not to display it for very long).

Long story short, I think it's just a bit of a tune job away. when I get back to the states (mid april), I'll probably send them back to Bill for a once-over. But again, thanks for all your help throughout this.


ok, enough chatter, here are the pics:

1 and 2 are the same thing, but 1 is a crisper image (though my body was blocking part of the pattern. 2 is a full image,but is shaky.

three is the diamond test pattern.
the fourth is the diamond pattern after the scanner has collapsed and the fifth is the standard ILDA test pattern on the collapsed scanner (before I reset)

[dave]

Are you scanning the ilda at full angle at 30k?

[Mr.Coffee]

Yeah, it's at 30 k and full angle (I haven't found out how to adjust the scan angle in livequick yet).

all the images were taken at 30 k, full angle, which Could be part of the problem itself.

[DZ]

Looking at the photo's the tuning on X looks very good, y is a little off but that doesn't matter since its X thats collapsing. Throw a solder bridge over that polyswitch and problem solved... Or do what I haven't had a chance to do, remove the poly switch and test it to see if its still in spec!

[dave]

Yeah, it's at 30 k and full angle (I haven't found out how to adjust the scan angle in livequick yet).

You can adjust the scan angle amongst many other projection related settings under-> Settings-geometric correction in LiveQUICK

[Mr.Coffee]

Thanks, Dave. I actually found that, and have limited the size to 70%. I figure while I'm playing around with this thing that I don't need the image to be huge anyway. I guess I should crack out the calculator and find out the scan angle.
I was really hoping that there would be a scan angle setting directly, but ah well.

but now I see what you guys are talking about regarding the noise issue with blue dpss, mine's got it as well, but I figure that's just something I'll have to deal with, along with the temptation to drop 2 grand on a red and green to get this up to full-color. that's a battle I plan to loose eventually, but at least not until I've picked up another tour ;-)


learning curves are great, aren't they?

[mliptack]

It would be nice to have a scan angle setting - although it would be something you would have to manually calibrate with every different set of scanners, since they are all different.

[carmangary]

A scan angle setting is not a bad idea. I think I will add that to my software and will allow the user to calibrate it by entering measurements of a square that I project and the distance from the projected image to the scanner. Thanks for the idea.

[mliptack]

Haha yeah when I typed that in I was thinking... hmmm Pangolin could benefit from this

So does spaghetti work with the FB3? I would like to try out the software

[buffo]

Mr Coffee;

Even a scan size of 70% may be too large for your DT-40's, at least when displaying a complex pattern like the ILDA test pattern. They're only designed to do around 15 degrees optical at 30Kpps. If you're running a complex pattern that is significantly larger than 15 degrees, that protection circuit is going to kick in every time. (Truthfully, that's what it's there for.)

You can scan simple stuff at greater than 15 degrees, but the ILDA test pattern has a portion (the center circle) where the scanners are running flat out (ballistic), and if you push the scanners beyond their limit while displaying that pattern they will just draw more and more current and get really hot while the pattern degrades. Eventually that poly switch will kick in.

I had this problem crop up quite a few times with my scanners. The solution is to back off on the scan size when running complex stuff.

When you tune your scanners, you should start with the scan size set very small and then bump it up a percent or two at a time. When you get to the point where the center circle in the ILDA test pattern stops getting larger, *STOP*. Back it off a percent or two and then tune at that setting. You'll find that the pattern will look a lot better! (And you still should be in the range of 12-18 degrees, depending on how good your DT-40's are.)

Adam