Rebuilding my old analog console

[lasermaster1977]

aah ha, so these are actually G-120PDs? or the newer 120Ps? So forget about my earlier schematic intended for non-PD GS scanners.

I agree with @mixedgas that the original GS A-601 position feedback scanner amps weren't all that. We used and preferred reproductions of the Laser Media LM22SDA amps based on this schematic shown below. I'm including the driver amp adjustment procedure and G100PD scanner connector pint config.

I've uploaded (for a 2nd time a much, much better) copy of the LM22SDA schematic that I just edited and is shown below. I've left the pin numbers off the left side of the schematic as they can be derived from the other LM22SDA pages from mixedgas' web link.









Attachment 60978

[Kevint]

Here is a freq ramp from low to 500+Hz. This is using the best and next best scan sets. Red = Best, Green = next best. I still have some noise in the system that I need to figure out where it is coming from.

Also, included picture of scan sets with mirrors and mounts

[Kevint]

For reference, my galvo inventory:

G100'S 8EA
G120'S 4EA
G124'S 2 EA
MFE R4-077 2EA

[Kevint]

Just for kicks, here are the commercial scan amps I got.

EC3 - Got this from Gary at Electronic Counter back in the day. I still have the manual. Last time I used it 30+ year ago it worked, but oxidation has destroyed some of the traces. Scared to try it.

Laser Fantasy Driver Card: this works but I do not have the manual anymore so I do not how how to set it up. If anyone has the manual that would be awesome.

[Kevint]

I could really use some mirror mounts for my galvos. If anyone has some they would like to sell, I would be interested. Could use 8 to 10 mounts.

[mixedgas]

I have the manual for that LFI someplace. I have a three channel just like it in a 19" rack. I'm away from home office for a few days, but I will seek it out when I have time.

EC3 looks remarkably like the 601.
Google:
"Skywise optics reference area"

He kindly hosted some galvo stuff for me "back in the day"

The full LM22SDA stuff is still there mixed with the other brand of Galvo stuff.

Ah, finally got my phone to produce a clean link:

https://www.skywise711.com/lasers/scanner/scanner.html

Keep the current in your Gxxx coils well below 1.2 Amps RMS, per the factory manual. Going above that can be a real dissatisfaction and a demagnetizing experience.

Steve

[lasermaster1977]

For reference, my galvo inventory:

G100'S 8EA
G120'S 4EA
G124'S 2 EA
MFE R4-077 2EA

So all of these are position feedback scanners (PD's) with one cable with coil wires and a second for the position feedback signals. Thanks for the ramp sweep video.
Using them with position feedback amps such as the GS A-601 or LM22SD amps would likely improve the phase shifting to some degree. However I think the one green beam pair has very poor frequency response behavior while the red beam pair is the expected behavior.

While mirror mounts are a convenience, you don't have to have them. We often epoxied mirrors directly onto the end of scanner shafts, although it has to be done very carefully and is somewhat of an art form in and of itself. Once the mirror is glued in place and the epoxy has begun to harden, we would mount the galvo with the shaft in a vertical position, mirror side down so gravity could help position the mirror on axis to the shaft.

One nice thing about the Laser Media drivers was the drivers were powered up with the 1 amp driver fuses "open" (one end popped up in the clips) and the scanners connected. The red/green LED was used to indicate a zero output voltage by turning the offset trim pot until the red/green LED was neither red nor green. Then the fuse was "closed" onto the fuse clip.

Maybe this was a common practice with other drive amps. The A-601 did not have this feature though.

I wish I had spare mirror mounts to sell you but I unfortunately do not. I do know someone that could make some but I would have to check on his work schedule.

[Kevint]

Awesome everyone.

Mixedgas: thanks for looking for the laser fantasy manual and the other info.

Lasermaster1977: thanks for the feedback and the laser media scan amp circuit. That will probably be my next build. And thanks for checking on the mirror mounts.

As I was looking to see if I could find any more mirror mounts in my stuff I came across this blast from the past. We used to pick these up at the TRW swapmeet for dirt cheap just to get the HeNe laser and power supply. Those were the good old days. We also used to get these Xerox laser printer modules with an ALC 60X argon ion laser in them. It was awesome.

[mixedgas]

Oh, so that's what they look like when intact. I was used to getting them parted out.

I've seen and salvaged Argon sleds, but never had my hands on the full HENE printer version.

BtW it's easy to mod a Xerox AO driver for analog in most cases.

Hold onto the gradient wheel, modern " no develop" holo film is cheap and easy to use.
.

Steve

[mixedgas]

Oh, so that's what they look like when intact. I was used to getting them parted out.

I've seen and salvaged Argon sleds, but never had my hands on the full HENE printer version.

BtW it's easy to mod a Xerox AO driver for analog in most cases. The AOs are fun teaching tools.
.

Steve