General Scanning G124-PD

General Scanning G124-PD - Has anyone ever heard of this model of scanner?

I know of the G124 which is a wide angle scanner (but not much good for scanning as it has no feedback), but the one I’m asking about looks like a G120-PD.

The reason I ask is that I have two of them and I can’t find any details on them.

Even when I purchased them second hand back in the early nineties I contacted General Scanning and they didn’t even know of them. So I’m assuming that they are either OEM or a beta model that never made production.

Interestingly enough though the serial numbers range up in the 1700’s (if that’s an actual indicator of how many have been made)

BTW, I am looking at selling them with the mount, mirrors and amps (GS A600)


http://members.iinet.net.au/~tcordin...S124PD%203.JPG

http://members.iinet.net.au/~tcordin...S124PD%201.JPG

Wow, looks like a G120 but with a G124 torsion bar. Never seen that before.

These look exactly like G-138's. I wonder if they were some kind of pre-G138 model. The 138 was nice because it had a much wider scan angle than the 120 because of the longer torsion bar like the 124, but had the feedback like the 120. Very neat item, I didn't know it existed!

Wow, I never actually realised that its torsion bar was longer than on a G120, I thought they were identical.

Interesting question. The General Scanning G-124 and G124-PD models were the open loop and closed loop (PD version) of a popular scanner in the beginning days of Laserium and into the 1980's. I used a set to do shows in a local college planetarium in the late 1970' (we could only afford the open loop version). Very solid scanners for the day and small as well, not cheap in 1978 dollars for college nerds.

The current technology has made great improvements in galvos with more accurate feedback for better closed loop speeds.

Thanks for the question it took me back down memory lane to my college days.

I also have a pair of G124s with the Feedback sensor installed. The T-bar on my pair is the G138 long T bar, a bit longer then the normal open loop G124 Torsion Bar..
Steve

Hey Steve, Those wouldn't be this actual pair would it?, I sent you these back in may 2013 :-)

Troy

I used to have a set of open loop g-124s back in the early 90s. Even open loop, they were pretty damn good. That torsion bar suspension would give the scanners around 5kpps~7kpps(estimating) performance. That doesn't sound great for graphics but for simple geometrics and abstracts, they were pretty awesome. You could get some basic text out of them too. Not bad considering xy scanning systems were well over $2500 and even more when you added a 3rd blanking galvo. Thinking about those good old days really hits me in the feels! I miss it.

A local surplus place about two years ago was getting in 2 new in the box or barely used g124s a week. From X-ray film printers. I was making weekly trips. I sold some, then built up a pile of personal reserve. The galvo that works no matter what, when all else fails.


Yes, Loopee, the 124pds are an interesting part of my collection. The sensors work, too. I fired them up the other day, but did not tune them yet.



Steve

Hi guys,

Well it seems that General Scanning has completely discontinued the old G-series scanners, including the G115 and G124. That's kind of a shame... Like some of the others reported on this forum, it was actually the very first real scanners I ever got my hands on, because they were less expensive than G120s, and because I could build my own driver for them.

Once they were officially discontinued, some customers started approaching us. They initially ask us if we could build one for them, but we don't have much interest in making an open-loop scanner, when it's actually easier to make a closed loop scanner these days. Back when I first started, optical position sensors weren't a gleam in anyone's eye, while today they're pretty commonplace.

Other than their use in laser lightshow equipment from the past, current uses include paint removal (laser cleaning) and some medical systems, including hand-held systems. I made a web page dedicated that discusses how someone might retrofit our Compact 506 into the same location as a G124. I was a bit surprised to find that the height was really similar, and -- as a test, we 3D printed a kind of "plug" onto the back-end of our C506.

Is there anyone here on PL who is still using the old G124?

https://www.scannermax.com/scannerma...ries-scanners/


Best regards,


William Benner

Quote:

---

Originally Posted by Pangolin

Well it seems that General Scanning has completely discontinued the old G-series scanners, including the G115 and G124. That's kind of a shame... Like some of the others reported on this forum, it was actually the very first real scanners I ever got my hands on, because they were less expensive than G120s, and because I could build my own driver for them.

---

The end of an era... :( I have such fond memories of the 124s. I bought my pair from MWK to replace their GAL-3 steppers. Stepping up to the 124s was a huge improvement. I used them with my Laser Illusion's PC Lite DAC. I could draw basic graphics and even text! They were so much fun! The good old days!

WOW, MWK... I remember speaking with them on the phone. They were in business long before the days of the internet.

I'm not able to find a web site associated with them. Are they still in business?

Bill

Quote:

---

Originally Posted by Pangolin

WOW, MWK... I remember speaking with them on the phone. They were in business long before the days of the internet.

I'm not able to find a web site associated with them. Are they still in business?

---

Sadly, they haven't been in business for many many years. I worked there for about 8 months in '97. After MWK closed, Mike Kenny used to sell a bunch odds and ends on ebay under the name hene1 but last I checked, there were no auctions going. You can see their old website on the wayback machine (prior to 2005) if you're feeling nostalgic :) I remember the catalogs they would send out. Martin Hasa was the graphic designer for the catalogs. I have never seen someone that skilled with CorelDraw. Downright amazing!

I have a "Reserve Stock" of G-124s for four purposes... One, When I am old and grey they will still work. Two. Open loop has its place in teaching and research. Three, I have enough of them to recreate a four head RGBY projector some day... Four, One G-124 can replace eight actuators in a beam table if you know what your doing.

G124s are really great for teaching how to make optical sensors for the robotics team I mentor. They needed a ranging system to map the inside of a pipe, so a combination of a camera, a galvo, and 5 mW of green works great for triangulation ranging in the 0-2 meter region where other types of accurate sensors simply blew the allocated budget. . Add a burst grating to that and the students did some amazing things with just the images and Excel, while using the Galvo for the initial distance. A hotel room toilet used for a late night calibration before the competition added a few new "dimensions" to their programming, when one found a quick way to store a calibration curve.

The advantages of a galvo over a servo become obvious quickly. Servos hog current, slightly oscillate at all times, and do maybe 0.4 degree resolution on a good day. Let me clarify one thing. To hold calibration we found we needed to keep the servos on, drawing battery. The T-bar is just as precise as a instrument grade meter movement, so the galvo could be powered down.

I've never broken a T-bar on a G-124, can't say that about a G-120. Besides, they are different metals in some cases, old man Montague used Nitinol on some of the longer ones.

One day the local surplus place had nine OEM G-124s new in the factory bags. I think if I could have hid my smile better, I would have had them for far less then fifty Dollars. That was around 2015, so they were still used in some medical imagers.

Bill,

You might want to rethink open loop. There is not much use for the R-4 or Gm20 because of cost of manufacture , but there is a small market for an open loop G-124 if you can drive the cost down to say 25 TO 50$ a unit minus amps. Then just use a LM3886 to drive them. Next week I have to float a tiny extrusion nozzle at 15 KV DC and shake it, and I'm using a G-120 open loop for that.. Given the industry sponsoring that research, the market could easily be 10-20K pcs per year.

Over the years I've seen more G-330, both open and closed loop, out in the wild, then anything else GSI... There might be a reason for that. You'd have to pry my cold, dead, hands off of the three open loop G-330 I still have, as you can wrap beams around the room with them.

End of an Era.

PS, The 506 looks really good with the mounting nub.

Steve

Quote:

---

Originally Posted by mixedgas

You might want to rethink open loop. There is not much use for the R-4 or Gm20 because of cost of manufacture , but there is a small market for an open loop G-124 if you can drive the cost down to say 25 TO 50$ a unit minus amps. Then just use a LM3886 to drive them. Next week I have to float a tiny extrusion nozzle at 15 KV DC and shake it, and I'm using a G-120 open loop for that.. Given the industry sponsoring that research, the market could easily be 10-20K pcs per year.

---

At the risk of turning this into a "dreaded" Pangolin thread, the vrad actuators are still available from ScannerMax. Not sure how the specs of the vrad 506 stack up to the G-124s but they definitely fit an open loop niche. I was actually looking at a pair of these for an open loop squiggle generator.

https://www.scannermax.com/products/actuators/

I use to drool over the mwk catalog. Always wanted their green hene and their argon lasers. Sadly it was not to be. Meredith Instruments showed pity on me and sent me a couple 1mw hene which I promptly used on speaker mirror scanners. That was what hooked me. I destroyed the first one on a neon sign transformer. I’ll never forget how exciting it was the first time I saw a dot of light flash out of the tube.

+1 for drooling over the MWK catalog!

I still have one of the MWK lissajous generators packed away in a box somewhere. That's about all I could ever afford from them...

Adam

Quote:

---

Originally Posted by Pangolin

Hi guys,

Well it seems that General Scanning has completely discontinued the old G-series scanners, including the G115 and G124. That's kind of a shame... Like some of the others reported on this forum, it was actually the very first real scanners I ever got my hands on, because they were less expensive than G120s, and because I could build my own driver for them.

Once they were officially discontinued, some customers started approaching us. They initially ask us if we could build one for them, but we don't have much interest in making an open-loop scanner, when it's actually easier to make a closed loop scanner these days. Back when I first started, optical position sensors weren't a gleam in anyone's eye, while today they're pretty commonplace.

Other than their use in laser lightshow equipment from the past, current uses include paint removal (laser cleaning) and some medical systems, including hand-held systems. I made a web page dedicated that discusses how someone might retrofit our Compact 506 into the same location as a G124. I was a bit surprised to find that the height was really similar, and -- as a test, we 3D printed a kind of "plug" onto the back-end of our C506.

Is there anyone here on PL who is still using the old G124?

https://www.scannermax.com/scannerma...ries-scanners/


Best regards,


William Benner

---

I still have a pair (or two) of the G-120PD scanners but have always used a DIY version of the LaserMedia closed-loop driver with them which performed better than the GS driver. I also still have my original G-115 open-loop galvos that got me started in the planetarium laser show business. All of these still work when I fired them up a few years ago.

Good times, eh?