How to tune your scanners

[tocket]

Just ask Norm. He did design the driver after all, and he's very helpful too.

[Frixxion]

^ Yea but if he built the kit from scratch he has to set it somewhere. He can't just leave it where it happened to be set when it came out of his parts bag.

Thank you, that's exactly my point . But you're right I'll have to ask Norm what to do.

[whiteg]

I have one question,

Why is that the Scanner ILDA test pattern is correct, (example: 30K 8 degree) but, the laser media test pattern is wrong the same speed and degree?
The lasermedia testpattern is correct if lower scanspeed. (25K 8degree), but then ILDA testpattern cicle is bigger.

This is correct scanner projection or not?

[buffo]

Why is that the Scanner ILDA test pattern is correct, (example: 30K 8 degree) but, the laser media test pattern is wrong the same speed and degree?

This is a sign that your scanners are not running at the same speed. The Lasermedia test pattern is very sensitive to slight variations in scanner speed between X and Y. Often it is difficult to see these subtle differences when looking at the standard ILDA test pattern, especially if you don't have a long throw and the pattern is relatively small.

If you had a very long throw and the ILDA test pattern was very large, you would probably notice that the center circle is slightly skewed to one side or the other. You might also notice a tiny bit of overshoot (or more likely, undershoot) on the dots at the corners of the center square. But these artifacts are difficult to see when the pattern is only being displayed a short distance (less than 20 ft) from the projector.

To correct this, you will probably need to slightly tweak the high frequency damping. Note: if the circle looks perfectly round and you have nice crisp dots on the inner square on the ILDA test pattern, then you are *very* close to being perfectly in tune, so the adjustments will need to be small.

Worst case, if you can't seem to get it right, then crank the gain, low freq and high freq damping down several steps on both amps (until the circle is definitely smaller than the square) and then start tuning again, but this time use very small steps and swap back and forth between the ILDA test pattern and the LaserMedia test pattern after each step to be sure the scanner speeds are equal.

Adam

[mixedgas]

The diagonal lines on the LM pattern measure if the scanner speeds are equal. If the lines "spread apart" or bow, one scanner is tuned faster then the other. If you have two different sized scanner mirrors on X and Y, the larger mirror will always be slightly slower with rectangular mirrors. This is why the latest Pangolin and Cambridge scanners have shaped mirrors with matched inertia values. If the corners don't match on the LM pattern, you have a damping error.

Steve

[whiteg]

Thank you for information, then I try the correct tuning.

[maddisr]

Hello, can someone explain where the dumping can be changed, is it editable in software. In Mamba 1.6 I didn't find these settings. Sorry, I'm a newbie.

[mixedgas]

Damping is a 10 or 20 turn potentiometer adjustment on each scanner amp. it is not a softwear function.

It is important not to rush in and adjust scanner amps. You should post pics first .

Steve

[Laser Wizardry]

" 15 characters"

[masterpj]

Upvoting this as well.
Well I tune first with blanking off to get a good view of the circkle and square and then turn off blanking.
The line in the bottom of the ILDA test pattern that I believe goes half way of the bottom and then turns up should not curve and perfectly overlap with the bottom line.
Get this right and your tuning should be spot on *if the circkle is right as well