DT 30 Scanner Manual

[mixedgas]

Mr Jors, I'm sorry, I'm only going to give you part of "ALL" your questions.

9-10-11 Notch filter module (Requires oscilloscope, signal generator to adjust, leave alone!)

If this amp is like the other "clone amps" you should have the following:

7. Input Gain (really is image size control)
6 High Frequency Damping
5. Low Frequency Damping
4. Servo Gain


"?" Velocity Testpoint for Oscilloscope

That should be enough for you to fine tune your galvos. Buffo's "steps" method is here: http://lasershowparts.com/files/Arti...20Tutorial.pdf

I really don't feel like typing 20 pages of text to explain the factory preset pots or the notch filter tuning. . I feel that for most beginning or intermediate users they are a great way to badly mistune a 2nd order feedback loop. You really need a test fixture and instruments to set them correctly and a video to train you. I went to a factory course to learn about them, and the manual (For the amp this was partially copied from) clearly states the reasons they should be factory adjusted ONCE only. Adjustment requires a oscilloscope, square wave generator, disabling the output amplifier and a precision means to measure angles. Funny thing, the Chinese must feel the same way, for they have never disclosed the adjustment co-efficient for the position sensor or the resonant frequencies for the notch. Without which variables, you can really, really damage the galvo core by overheating, and in the case of the notch filter, really degrade your images.

The notch adjustment is quite subjective. To do it you well, your really need to have a few sets to learn from. I actually remove it from systems I build, in most cases its un-needed.

So for the same reasons as Bill explains below, some things are best left alone. After all the amps would be pretty close to meltdown , unstable, or not working at all if the other pots were mis-set at the factory..

HFD, LFD, and Servo should bring out the best in your images.




Steve

[jors]

Many thanks Steve!!
I much appreciate your response.

Cheers

[Pangolin]

In this document on our web site, I show three separate versions of the DT amps, with pots labeled and at least some discussion of their functionality:
http://www.pangolin.com/_Files/C506_AmpMods.pdf

[buffo]

Just a reminder to anyone working with the Dragon Tiger amps: on some of the DT-40 amps, the primary tuning pots (servo gain, low frequency damping, and high frequency damping) are all wired BACKWARDS. That is, turning the pot clockwise causes the setting to decrease, not increase. This can be very confusing if you're not prepared for it.

The document that Bill referenced above states that the green PCB amps are all wired this way, but in my experience it's more of a coin-toss. Of the 5 sets of DT-40's I've worked with over the years, 2 of them were wired backwards like this, and they've all been the green PCB amps. (I've never tuned any of the "red board" PCB amps.)

Either way, it's something to keep in mind.

Note: I've never run across this issue with any other scanner amp. It seems to be a manufacturing bug that is unique to the DT-40's. It might also affect the DT-30 and/or DT-20 amps, but I've never run into a case myself.

Adam