Help tuning ScanPro20's

[seanharrison]

I have recently got my scanpro20 back from being repaired again, Now thing time, i wasnt going to use a SoundCard DAC because i have had alot of trouble getting it to work correctly and didnt want them damaging again. So this time i have gone a step futher, I have brought an Easylase dac. So i've unbox and mounted the scanners again, and fired them up using the easylase test program with the 12k test ILDA pattern. It all fires up....

Straight away i get a very rounded shape with few lines and dots here and there, The tuning was well off, I turned up the gain a little bit and it became more square, but still misshapen with no detail, it doesnt look anything like the ilda test tho. So since then i have spend many hours, following the steps from buffo's tuning guide. I have finally got something that looks like the test pattern, but its still not 100%

I have tried this several times, but i am now stuck and can't seem to get it to look any better. I have taken a few photos and vdeos.


ILDA @ 15K



ILDA @ 20K



Grid @ 20K



Lasermedia @ 20k



Quad @20k


3 Videos:

http://www.youtube.com/watch?v=VOkql_vAyyw
http://www.youtube.com/watch?v=ufIKAcrtNRk
http://www.youtube.com/watch?v=UbX2lcXag9o



On the Quad, I can reduce the overshoot on the top left and bottom right, but doing this destroys the ilda test pattern when i switch back to it, also i can not reduced the overshoot on the top right or bottom left,



Any suggestions on how i can resolve this ?



Thanks,

Sean

[allthatwhichis]

Patients is the key. I would start with your X axis as that is where the over shoots seems to be and work all three pots all the way down a little at a time until any one starts to give you a mess (in my experience High Freq Damp will give you a mess first as it needs to be adjusted least.) and then bring it back up a bit so the scanners are freaking; bring the other two down until one of the other two goes (usually LFD for me). Then usually the last one to go is your gain and it'll collapse that axis. Work your way back up with the gain and low freq damp until you need the HFD; and then on with buffo's tutorial. Getting them to zero has always been the key for my tuning; and I usually start with the worse of the two and then I might even go back and forth once or twice, all the way down to zero and back, to be sure I got them both optimized.

[seanharrison]

I will give it another shot tonight and see if i can clean it up anymore, Does it just look like a tuning problem, When trying to Zero it, the X seems to act strange, I keep lowering it, but at a certain point, the whole image distorts and goes rounded.

Thanks for your help

[buffo]

Does it just look like a tuning problem?

Hi Sean;

Yeah, it looks like a tuning problem! You've got a ton of overshoot on the X axis. As for the Lasermedia test pattern, it appears that you have the gain for both scanners set very low. That's OK, it just means you are near the bottom of the stairs. But you've got a long way to go to get them right.

When trying to Zero it, the X seems to act strange, I keep lowering it, but at a certain point, the whole image distorts and goes rounded.

That could mean you're taking too large of a step when you're lowering the pots (trying to zero them). If you dial the HF damping and LF damping back too far, you'll end up with massive overshoots, and eventually the scanners will start to resonate. (This is BAD!) Remember: small steps. (This applies when you're going down the stairs as well as up the stairs!)

However, in your case it looks like you've got another problem going on - namely that your blanking offset is not correct. The top pairs of lines of the pattern should be bisected by a short vertical segment. But the vertical segment in your pattern is *way* off to the right. Try adjusting your blanking offset first and see if you can get the vertical line to be more centered between the top pair of lines. Then see if the overshoot that you couldn't get rid of goes away.

From there, you should be able to follow the tutorial to finish the tuning. Post pictures though, and we'll help you through it.

Adam

[seanharrison]

Try adjusting your blanking offset first and see if you can get the vertical line to be more centered between the top pair of lines. Then see if the overshoot that you couldn't get rid of goes away.

I am using the Easylase Test Software to display the test patterns, (*i dont have any other software apart from popelscan*). There does not seem to be the option to change the offset . I was thinking about this issue, do you think that one of DZ's color boards would help me correct this offset issues, i know it has delay features ?


Sean

[buffo]

Hi Sean;

Sorry for the late reply - been busy as hell at work recently!

DZ's board will introduce more delay, but I don't think it can shift the delay enough to compensate if your delay is off by 2 or 3 points. (Need to check with DZ on this though, as there may be a fix he can add to the board to give you more delay.)

Is there any chance of you getting together with someone local to you that has a Pangolin system? If you could test it on a QM-2000, it would be very easy to tune the scanners. Then, when you connected it to your system you could be certain that any problems in the image are a result of either the software or your sound card controller and not the scanner tuning.

I ran into this problem back when I was experimenting with a sound card DAC too. I didn't want to pull the scanners out of my projector, so I set up a spare set of scanners on a breadboard with a 100 mw DPSS green laser and hooked it all to the sound card. But since I didn't know if the scanners were tuned or not, I had a hard time setting up the correction amp. In the end I had to tune the amps with them connected to my Pangolin QM-2000 first, and then hook up the sound card DAC and adjust the correction board. (And I never did get it perfect, but it did work - sort of...)

Adam

[seanharrison]

Hi Adam,

I will see if i can find someone who can help me get them tuned, Stanwax is not so far away and has offered to tune them for me, I will have to get in contact with him,

Also, I am no longer using a soundcard DAC, This images when taken while using an Easylase DAC.

If i was to use other software i.e. Mamba would i be able to change these offset's ?

Sean

[Things]

I wasn't able to run my scanpro 20's at the full 20K speeds, but they perform pretty well at around 16-18K once tuned. I was never able to get the text at the bottom of the ildatest readable, but since the SP20's are somewhat cheap they aren't going to be the best performers to be honest.

[buffo]

Stanwax is not so far away and has offered to tune them for me, I will have to get in contact with him

What's that? Rob is local to you, and has offered to assist, and you're still here talking to us? What the hell dude?

Pack those scanners up and *run* over to Rob's place. He'll get you on the right track in no time at all. (Be sure you have enough time to take him out for a beer afterwards though. You'd be amazed at what you can learn from him over a pint or two!)

If i was to use other software i.e. Mamba would i be able to change these offset's ?

I don't use Mamba much these days, but I'm pretty sure that there is a "shift" setting in the output settings window that will adjust your color shift point-by-point. Rob will be able to verify this, as he also has Mamba and has made quite a few shows with it.

Adam

[ElektroFreak]

There must be considerable variation in the quality of the factory tune on SP20s. I have a set that was tuned nearly perfectly from the factory and remains very well tuned (even at 20k), but I've heard of other people that have not had the same luck.