Degrading scanners.... WTF ?

[James Lehman]

How good is your sense of smell? Do you smell any fried electronics? Do you see any bugged out electrolytic caps? Any goo on the amp boards that wasn't there before?

Were the trim pots glued in a position before they got tweaked?

Maybe you have a flaky solder joint; although it seems odd that BOTH scanners are weird now.

James.

[Stuka]

Good sense of smell. No sign / odor of any fried, bugged out, or gooey electronics. The trim pots WERE originally glued in place.

No VISIBLE flaky solder joints, but that doesn't necessarily rule it out.
Might be time to pull out the ball-peen hammer...(well, maybe in the morning)...

[Pitts]

Hi Stuka..

I see this from time to time with different drawings I have....
Is this your RGB ?? or greenie ?

It would be hard to believe that you would need to re tune so soon. (unless something has died.)

Have you done some real simple pix like just a circle etc etc..

What does the ILDA test pattern look like ?

I built the delay circuits for my RGB and they help no end BUT more in terms of time alignment of the beams.

Have you asked Bill ?? If those multi turn pots are crappy ones they may have moved.

Suggest post some pix on PL that will liven up the gurus on here.

I'll be interested to see the outcome as I have been chasing a bit of a ghost on this myself but I think its just me learning the correct way to "think" when you are entering points in LD2000... like how the scanners re act to the different ways the blanking lines join different parts of the pix together.
I've got to learn to make it easier for the scanners, not harder... does any one offer a language course in "scannerese" ??? Chinese would help as well.
That point "entry" order makes one hell of a difference in the final pix so I am learning.

Gotta gotta gotta learn to think like a scanner !!!

Cheers

Ray
NZ

[Admin]

Ok. Me and Mr.Guzzlebucket(Bottle of Islay Scotch) have spent some quality time together this evening and my options are "walk around the room pretending to be a modern day cyber-pirate" or vomit all over this thread. Since I can't find my tricorn, this thread better wear some scuba gear.

If you want to skip the fluff, here is a general summation: "But hey, at least they are cheaper, in all definitions of the word, than Camtech!"

I've never met a Chinese scanner I've *really* thought "Wow! How did they kidnap a Camtech engineer!"

But thats never stopped me from trying to desuckify these things.

I have never played around with a set of the laughably named scanpro's but galvos are, at the surface, pretty simple devices with damn near identical designs so this should be pretty easy.

Mark my words: Irony being what it is, there will be a Chinese company in the future named "Ultra Super Perfect 120K High Speed Laserist Servo For Great Justice Inc".

As scanners age they go limp, unfortunately Pfeizer has not made a Viagra variant for them but we can get pretty close with the tuning pots. The difference between GS, PI, Camtech and Chinese galvos is the rate in which and how they age.

To make up for this aging problem you get access to tuning potentiometers that can, in effect, clue-by-four a galvo back in check.

Now, with regards to most chinese galvos they just visually copy the design of a Camtech 6800 without really understanding why the specific parts are there, hence why you see a lot of shit floating around.

They replace the expensive narrow source LED's with commodity canners, they replace ideal bearings with commodity japanese ones, photo detectors are not in ideal locations, the rod's are commodity "Whatever they can get their fucking hands on" n40-ish magnets, end caps are press fit. Magnet wires are hand wrapped, shoved, and epoxied to to the shaft without even a thought of thermal dissipation, much less the totally creepy vector field known as magnetic flux. Im getting fucking tired of seeing "Butterfly" galvo windings. ITS CALL THE RIGHT HAND RULE, MOTHERFUCKERS. Dont even get me started on these pieces of shit they call mirrors.

In short, I believe that somewhere during the construction an engineer says "Meh, It looks like a cambridge, close enough." and calls it a day.

I and the bottle of scotch have read a ton of threads here about scanpros(haha) here and I would be willing to bet the bearings are going to shit in quick order.

Very gently actuate the mirrors from one stop point to the other, you should feel some friction there.

If you do, they either used commodity bearings or didn't load it right causing torsional stress, either way the product is the same, the balls in the raceway are being eaten alive and flaking off steel into the raceway which interestingly enough(from my perspective) accelerates the degradation of the galvo.

Another possible theory is that the epoxy they used is also commodity and got soft under the heat and sprayed everywhere. By the powers of Greyskull^H^H^H^H^H^H^H^H^HScience the epoxy ended up in the bearings and basically coated the raceway in the mechanical equivalent of a sandpaper condom.

Honestly, I use DT40's. 1/3 the price of Camtech and 80-ish percent the same. The other 20% accounts for all the little quirks, which in my not so humble opinion are work-around-able given the cost. We have a history and yes, I am biased. Ohh, and I like my HFD pot when I gut that useless notch filter thank you very much. And one more thing, "x thousand points per second" is this industries version of the "megapixel" it really doesn't mean much but gives people a friendly variable to base purchases on.

Now before you get your knickers in a knot, xKpps *means* something to cambridge, they really do use the term on the straight and level.

Ohh, the bottle wants me to "spare a word" for Cam now. The synthetic ruby bearings need to have a come back tour. I understand you have a vested interest in keeping your bitches in check and coming back for more blow but really... Seriously... What the fuck.

China is really good at doing a couple things: 1) doing exactly what you tell them and 2) having a populace large enough to make SMT machines not "economically viable". Let that sink in for a second and then think of the consequences of not telling them "exactly what you want"

Or not. Either way, I can't find my tricorn. Yar.

[allthatwhichis]

Don't mind the janitor... We only let the bottle of Scotch take him out for a walk on holidays. Happy Labor Day.

[Jem]

the epoxy ended up in the bearings and basically coated the raceway in the mechanical equivalent of a sandpaper condom.

Beautiful, just beautiful... Such graphic description and eloquent use of the english language. Have you ever thought of taking up poetry?

Jem

[Admin]

Haiku's are easy
But sometimes they don't make sense
Refrigerator

[Stuka]

Haiku's are easy
But sometimes they don't make sense
Refrigerator

Spec - you "ain't right"...but your spin on my scanner issues, while both sad and true, did give me a chuckle!

The mirrors appear to be turning smoothly, so I guess I'll let them run a test pattern for a while and try re-tuning. If I can get them close, I think I'll put a drop of removable loctite on the trimpots and hopefully lock them down for a while!

[Stuka]

Update...

After running the ILDa test pattern non-stop for a couple of hours, I definitely see some degradation in the patterns. I've double checked all the software settings, and I'm scanning at a consistent 30K with 8 degrees scan angle.
The scanners themselves are running very cool, as always. The scanner amps and power supply are only slightly warm - definitely nothing unusual.

The ILDA pattern shows the "ladder" at the bottom of the pattern starting to collapse, along with the Y-axis of the center circle. The upper-left and lower-right of the outer square are rounding.

The laser media test pattern shows a separation of the diagonal retrace lines, as well as degradation in the overall pattern.

The color wheel pattern shows the inability to draw complete circles, as seen in the overlapping lines and "tails" in the circular patterns.

Any suggestions on where to start re-tuning WITHOUT starting over from scratch?

Thanks!

Randy

[gottaluvlasers]

im waiting for adam to jump in here but to ME it looks like something is being over driven. those circles (ovals) with the distroted tails is usually a tell tale sign of being overdriven.

now HOW they got overdriven since 2 weeks ago at selem is a mystery to me. is there a bad ground somewhere on your machine? (not that that would cause over driving, more noise so to say!)

have you tried completely re-tuning form scratch? i know it SUCKS! but maybe after re-tuning you may come across an issue. maybe a gain pot is broekn on your driver board? maybe something as simple as that. (a pot not soldered down too great!).

if you start form scratch, you may get to a point where you say, "oh shit...this isnt working..."

is your computer and your projector on the SAME circuit? i know that can casue some problems sometimes if they are not. 2 different gound potentials between the puter and the projector could cause some issues.

my suggestion is a re-tune. unfortunately.

-Marc