DT40 scanner problems

[buffo]

Thanks for the follow up, Fuzcub. Interesting phenomenon... I don't know that anyone here has ever reported that before.

Though I can't see Andy's pics at the moment (stuck at work behind a firewall), I can visualize what you're talking about re: his projector layout.

Andy, have you tried removing the amps from their mounting (or even all the way out of the case), just to see if the problem gets any better?

Adam

[andy_con]

no and ive not tried the tuning you suggested yesterday as i put my red in instead.

im just about to try the tuning now and ill get back to you

[andy_con]

it now looks like this

[buffo]

Damn, that still looks bad Andy. Can you turn off blanking (or just disconnect the blanking lead) and post a picture of the test pattern with blanking off? It would really help if you could also post the test pattern rotated 90 degrees, again with the blanking off.

You might want to try fuzcub's idea and just remove the amps from the projector housing. See if taking them away from the PSU and the fan changes the ripple any. If it does, then you know you've got a noise problem.

Adam

[andy_con]

yes ill do that pic tomorrow.

i think im ust gona leave it for now, ill out it back to how it was so the circle is whole

cheers for trying

[Pangolin]

Hi guys,

The notch filter most likely has nothing to do with this problem. In fact, yes, I recommended that Jain remove the notch filter (and also perform about a half dozen other changes). Sadly (amazingly?) he did not take my advice on anything I recommended... I know this because another PL member recently had Jian send me a set of DT-40 directly to Pangolin, to be modified and paired with a FB3 system we will soon be shipping.

I have done the mod to a number of PL members' DT-40 scanners. For those interested, you can see a brief report I made here:
http://www.pangolin.com/_Files/DT40.pdf

I have kept that report private, and sent it to Jian on September 25, 2007, so that he can improve his scanners (not only for himself, but also for all of his users and people purchasing scanners from him). Clearly this is no financial benefit to Pangolin. We just like to have equipment out there that is as good as possible...

As you can see, my mod actually makes the DT-40 easier to tune. Without the proper equipment (which almost nobody has), it is impossible to tune a notch filter. So... get rid of it! Also, Jian has unfortunately proven time and time again that he is unable to properly tune high frequency damping so... get rid of it!! By removing components, reliability is actually increased. So these changes not only improve performance but also reliability too...

Anyway, andy_con, if you want to send your scanners to me, we'll crank them up on the DSA and get them tuned up like clockwork.

Best regards,

William Benner

[andy_con]

thats a real nice offer and im so so tempted, as i have an fb3. but ive only just got my scanner up and running.

it would mean being without a working scanner for probably a month, so i might pass.

they dont display the test pattern well but they display other things just fine.

[buffo]

I don't know Andy... You're waiting for your green laser to show up anyway. If I were you, I'd send them to Pangolin via Express Courier. Sure, it might cost a little more, but you could get them back pretty quick that way - maybe even before your green laser arrives - and then they'd be tuned to perfection!

Seriously, if Bill offers to tune your scanners, take him up on the offer!

Adam

[andy_con]

i know its so so tempting.

i cant do anything till next week anyway as the meet is sunday.

[Pangolin]

We could turn it around pretty quick. Hayden would perform the mod, and then we crank them up on the DSA and do final check out. It doesn't take much time to do these things (especially since we are basically removing parts, not adding them...).

Perhaps some of the PL members for whom we have modified and tuned their scanners will comment...

Best regards,

William Benner