Any Laser enthusiasts here? - Page 1
Forum section: electronics / general

author: TerraHertz
author_rank: Super Contributor
timestamp: October 26, 2018, 10:09:31 am
content: A friend of mine bought a junked Quanta-Ray model DCR-2A(20) Q-switched pulsed gas laser at auction some years ago.Made in 1983, it's BIG.He'd hoped to get it going, but there was quite a lot of damage and missing pieces in the optical head, so he gave up.Fast forward, now he's moving, and didn't want to store the giant power supply any more. He gave it to me.He kept the optical platform, since he does do some other laser stuff like computer controlled laser light shows.So, I now have this enormous gas laser HV power supply and control unit.Before I decide whether to totally scrap it for parts, or keep some or all of it intact, I'd like to find a schematic if possible.Does anyone know where I might find one? Google fails me.Briefly I was really pleased, thinking the cooling water loop pump in this was exactly what I needed for another project.Then noticed the pump motor is 115V 60Hz. Dammit.

author: Martin.M
author_rank: Frequent Contributor
timestamp: October 27, 2018, 09:59:53 am
content: good luck.I have only a very small system in the collection, build like a pipe with integrated PSU, seems to be a tube laser system, made by Rofin Sinar.It is full working, red.

author: ajb
author_rank: Super Contributor
timestamp: October 28, 2018, 04:51:04 am
content: Your best bet is probablyPhoton Lexicon. There's a lot of concentrated laser nerdery over there.You say gas laser, but from what I see on Google the Quanta Ray series is all pulsed Nd:YAG/dye. Pulsed lasers aren't something to be trifled with, and many of the dyes used in laser applications are notoriously nasty (like, spill some on your skin and die, according to some stories I've heard). YAGs are often pumped with flash lamps, sometimes in an elliptical reflector cavity next to the YAG rod, all flooded with cooling water, so you'd expect to see lamp driving circuitry as a big chunk of the supply (actually, your control panel shows two lamps, which I've seen references to, but not sure how the second lamp is used). You'll also have a supply for the Q switch (pockels cell?) and a lot of the rest will be system monitoring, interlocks, and then support for whatever else is in the optical section.

author: Psi
author_rank: Super Contributor
timestamp: October 28, 2018, 05:18:14 am
content: +1 for Photon Lexicon. The people on that forum are second to none when it comes to lasers.Some of the members their have built lasers with lines at wavelengths never created before.They will be able to tell you what all the parts are and what is valuable. You may also get good offers for parts.Just tread carefully, people there justifiably get a bit worried if they think someone without any laser knowledge is playing with a high power laser.

author: purfield
author_rank: Regular Contributor
timestamp: October 28, 2018, 06:05:55 am
content: I have a Spectra Physics HIPPO 17W Q-Switched DPSS laser that's pretty fun to use. I've even made PCBs with it!

author: TerraHertz
author_rank: Super Contributor
timestamp: October 28, 2018, 09:09:54 am
content: Quote from: ajb on October 28, 2018, 04:51:04 amThanks! That's the kind of resource I was hoping for.QuoteNope, it's DEFINITELY a purely gas laser.(Doh! See next post)Sorry I don't have photos of the optical section, I forgot to take any in the limited time we had to get the electronics separated from the (damaged) optics and into my car. I'll get some next time I see my friend.Btw I don't even know which gas. But I have the gas flow reg and filtering parts.Probably Quanta Ray _now_ make only Nd:YAG lasers, but this was built in 1983.QuoteYep. Though lasers are not in my hobby list, I'm aware of the general types and principles.Currently I'm tracing out cabling and functional sections of the system. Not to use as a laser PS, but to see if the power supply sections may be generally useful. it appears to use thyristor phase control of charging the capacitor banks (to variable level to control pulse power), then some even more beefy thyristors to supply the two cavities, plus twin HV ignition circuits, plus one neat little HV pulser driving the Q-switch.In this unit the main power supplies are duplicated, since the optics has one Q-switched cavity, then the pulsed beam leaves via a second 'amplifier' cavity. Which is nice, it means the really heavy duty power circuits and their controls are all duplicated.Quote from: Psi on October 28, 2018, 05:18:14 amUnderstandable. In fact the risks with high power lasers are why such things arenotin my hobby list. I'm OK with deadly high voltages, but not with invisible beams that can bounce off some shiny surface across the room and instantly permanently blind you. No thanks.Edit to add:I'm hoping it might be hackable into something like a small contact spot welder (battery tabs?), pulsed jewellery TIG welder, sputtering source in my vacuum chamber... that kind of thing.

author: TerraHertz
author_rank: Super Contributor
timestamp: October 28, 2018, 10:24:57 am
content: Huh, it seems I'm wrong and it is a YAG laser.By amazing coincidence the very first thread I looked into at that laser forum was this:https://photonlexicon.com/forums/showthread.php/27167-A-big-YAG-followed-me-homeAlmost the exact same unit. That's a Quanta Ray DCR-3, while mine is a DCR-2.Some good photos there of the optical section, that is almost identical to the one from this unit.So, I guess the two big aluminum blocks contain the YAG rods plus flash tube. They are water cooled.And the gas feed is just to fill the optical path with clean, dust-free gas of some kind.The Q-switch is the small white cylinder at left in this image:https://photonlexicon.com/forums/attachment.php?attachmentid=54243&d=1529873813&thumb=1I was a bit sad to see this system broken up (more), but that's what my friend wanted to do. And I wasn't going to turn down the power supply.

author: Lord of nothing
author_rank: Super Contributor
timestamp: October 28, 2018, 04:10:31 pm
content: Sure speciality that one who can bring the Keyhole Sat out of Business.

author: james_s
author_rank: Super Contributor
timestamp: October 28, 2018, 05:47:05 pm
content: Sam Goldwasser is THE guy for all things laserhttp://www.repairfaq.org/sam/lasersam.htm

author: TerraHertz
author_rank: Super Contributor
timestamp: October 30, 2018, 12:05:31 am
content: I'd sent an email to Spectra Physics, (who currently own the Quanta-Ray line of lasers) asking about schematics/manual.Here's the reply:QuotePretty much as I'd expected, but one has to ask. At least there's one useful bit of information - the old manuals did include schematics.As with so many companies, up until sometime in the 1980s there were decent, civilized engineers in charge, who understood they had a moral duty to provide schematics when they sold machines. Then later the filthy degenerate lawyers took over, and "sorry, 'liability issues', no schematics for you."Well then. I'm still looking for an 'older manual' for it. PDF or preferably original paper.If anyone has a spare paper copy with schematics, I'd l like to buy it. It would get scanned and posted.In other news, I discovered that some time in the last decade this machine was exposed to water. Maybe just dripping on one part of the control panel. Result: water got into one of the meters. I'd noticed the face plate in one meter was a little corroded. Thinking it was just on the dial plate I opened it up for cleaning. Urrgh! There'd been a pool of water inside the case for a while at some point. Meter movement is completely destroyed. The other meter has very very slight corrosion, but is functional.I'm still keeping in mind a faint possibility of restoring the machine to function (if my friend decides he doesn't want the head optics after all) so now will see if I have a compatible meter movement in my old meters collection. Maybe. It was a good one: 500uA taught-band movement.Meanwhile, scanned and photoshopped the corroded meter face. The 'cleaned up' image is not finished.Even for other potential uses of the power supply, a Joules/pulse meter may be useful.

author: Suresh94
author_rank: Newbie
timestamp: March 22, 2019, 03:51:05 pm
content: Hi, were you able to find the schematics for it ?thanks.

author: Brumby
author_rank: Unknown
timestamp: March 23, 2019, 03:55:45 am
content: Quote from: TerraHertz on October 30, 2018, 12:05:31 amI have sometimes wondered about that "liability" claim. Being moderately competent in probing around inside an electrically powered item, I would have thought there was greater risk by manufacturers NOT providing schematics.With a schematic, I can approach from an informed position. Without it, I am forced to exercise my own judgement - which may be lacking in some non-obvious way.Without a schematic, I may end up doing something unwise which I would never have ventured near, had I had a schematic.As it is, I tend to sit down with an unpowered item and try and draw up a schematic, particularly of higher voltage sections. Bit of a pain, but it beats time and money spent on medical treatment.

author: james_s
author_rank: Super Contributor
timestamp: March 23, 2019, 03:59:47 am
content: Blame the lawyers for that. If they don't help you and you hurt yourself, you did it on your own. If they do send you information and you hurt yourself, it could be argued that they encouraged or enabled you do do something dangerous. I don't agree with it but that's now things are now.

author: Brumby
author_rank: Unknown
timestamp: March 23, 2019, 04:21:15 am
content: I sometimes wonder what the situation would be if you formally requested the necessary information and it was refused ... andthenyou hurt yourselfbecauseof that lack of information.