View Full Version : Guess I need to tune

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03-21-2008, 04:09
Hi All, heres a vid of my scanners. They have not been tuned at all. I like beams more, but there is some funny things happening when I display certain images...watch what happens when I dispplay the test patterns...


It displays the pattern (very badly) then is goes all scewif :confused:


EDIT::Waiting for google to aprrove the video

03-21-2008, 06:04
Hmmm, I do no see no test pattern. Just two dudes laughing for a second... :confused:

03-21-2008, 09:11
Whoopsy daisy, wrong vid..
try this one

03-22-2008, 01:08
Anyone have any idea whast happening here?

03-22-2008, 03:41

Are you running the DT-40 scanners? (I seem to remember that you were...) To me it looks like the poly switch is cutting out on you... (At least, that's what it looks like in the video.) My guess is that you're trying to scan the pattern too wide, and the over-current is causing the poly switch to cut out. This is a common problem with the DT-40's if you over-drive them.

This assumes you're running the DT-40 scanners, however. If you're running some other scan set, then you need to look deeper.

If you are running the DT-40's, then here's what I'd do:

1) Reduce the scan angle to around 10% of normal.
2) Display the test pattern again and see if it looks like it should.

If it's still screwy even when you're displaying it at just 10% of full size, then something else is wrong.

However, if it looks OK at the small scan angle, then do the following:

3) With the test pattern still displayed, start increasing the scan angle and watch the circle inside the square.

4) When the circle *stops* getting larger, STOP! Back off the scan angle by a couple percent.

Now - at this point you are running the scanners very close to their max scan angle for that speed. Look at the test pattern. If it looks good, then you don't need to tune, and your problem all along has been that you were trying to scan a complex pattern at too wide of a scan angle.

On the other hand, if the pattern still looks lousy (circle is distorted into an ellipse, or it's outside the square, or it doesn't touch the inside of the square, or there are overshoots or undershoots on the corners of the square), then you should tune the scanners with the scan angle set right where it is.

And bottom line: if you try to display any complex pattern (including the ILDA test pattern, but also including many abstract patterns, not to mention complex ILDA frames) at a scan angle greater than the setting you're at when you tune, you'll end up with the same problem. (The poly switch will cut out and the image will look like crap.)


03-22-2008, 09:29
Thanks Adam, they are 20K Scan ECO.
They scan badly at most % but if I reduce scan speed right down untill the limage fliker like anything, the pattern is then displayed correctly.

03-22-2008, 12:39
Hmmm... I've worked with those scanners before, and I never had the results you posted in that video above.

You aren't trying to run them faster than 20Kpps, are you?

If you have the scan speed set correctly, it could be that you're still driving them too hard. Try scaling back on the scan angle and see what happens.

One thing about a set of 20K scanners - no matter who makes them - is that they're going to create flickering images. Heck, even if you have a set of Cambridge 6800 scanners and you run them at 30K, you can still get some flicker.


03-23-2008, 08:14
Fair enough...I'll play more with the scann angle.

03-23-2008, 08:22
Man I had those same scanners and Adam took em to do the review on them. They are solid scanners. Even un tuned I got a good pattern at 20K 8 degrees. They rocked for beam shows. :cool: You should be able to tune em right up for OK graphics.

03-23-2008, 08:30
I tell you what, these scanner make some excellent noises depending on the pattern, I am intending to record the noises and make some music form it, techno techno techno techno :p