Stoney's First Argon - ILT 5490A

[Stoney3K]

Today I went to Laserwinkel's to pick up the ILT argon head he was planning to sell me for about 6 months now.



The PSU and head as pulled from the Datronik casing. I did a test run and confirmed the whole lot was in working (and lasing) order before I took it home on the train. I must admit, there was something funny about turning heads when carrying a beige box which has a huge 'DANGER' sticker slapped onto it.

The head is in near pristine condition and the hour meter reads just over 500. During the test run, the laser power jacks read a voltage of about 0,121V (which, I guess, would be 121mW) and the current measured in at just under 8 amps. That is, until I discovered the Datronik had some switches on the back and could kick the whole lot into a 'high' setting. This was about 10,9A current (which, AFAIK, is maxing out the tube) and a power meter reading that was rapidly climbing to 300mV and beyond. I didn't run it on that setting for long because I wouldn't want to risk any runaway.

The ion got home safely but I haven't been able to run it in an isolated environment yet: Unfortunately the power supply (an ILT5400 switcher) was subject to some not-so-subtle aftermarket hacks which I need to repair first. More specifically, remove the 4 pin DIN jack that was used by the modified Datronik to control this unit in the first place, it has pins on it that read +, -, TTL and no connect, but I will need to take out the mod to find out what the original function was. Ultimately, I just want to put back a proper keyswitch and control the power with the little pot that's on the head (which is the intended mode of use).

Has anyone got some schematics or other useful information for the 5400 series? I've found plenty of useful data on the tube but hardly any info on the power supply. My first goal is to return this unit back to its original condition.

[mixedgas]

Has anyone got some schematics or other useful information for the 5400 series? I've found plenty of useful data on the tube but hardly any info on the power supply. My first goal is to return this unit back to its original condition.[/QUOTE]

In 20+ years of working with lasers, I have never seen a ILT schematic. Nor a JDSU schematic.

These are the guys who inherited ILTs IP, I have sent many people to them over the years, but they seem to be very shy, unless you have your checkbook out.

http://www.dzlaser.com/index.php?ID=75

Steve

[Stoney3K]

Never mind, I fixed it already.



The power supply has been modified to allow interlock and current regulation from some outside device (like an ILDA jack) without the need for the (probably quite expensive) original ILT remote controller. An extra circuit board with a relay and some analog magic was added and gives you two voltage inputs: One for laser power on/off, and one for current control. A few minutes with a soldering iron later, and I built the most elaborate power button I could imagine...



Just two lab power supplies, as I was too lazy to hack up a 6VDC wall wart adapter for the on/off voltage. Right-hand one controls current (which is at 0v, happily idling right now).

When it was built in the Datronik, somebody took a bit of artistic liberty and figured that 'idle' would be around these readings (Power on the left, tube current 10mV/A on the right):



Obviously, he wasn't doing his job.



Much better! I can dial the current down to under the lasing threshold if I wanted to, but I'm a bit reluctant to do so at the moment because I don't want to risk any tube damage.

A quick crank up to a tube current of 10A (Imax = 10,9A), which I don't intend to repeat ever so often:



If this meter is right, I just made a whopping 310mW of cyan out of this thing. Whoa! For an ILT 5490ACM, this is seriously over spec and I guess there will be plenty of photons left in this thing for me to enjoy. For normal runs on show-day, I'll stick to about 9 amps of current and 250mW of laser power, which should be more than enough for a lot of gigs.



Brightness comparison at 9A (250mW) with my 50mW DPSS green labbie which is outputting a little more than it advertised for. But it's never going to beat a pencil-thin blue beam.



Divergence test: Spot size of 10mm across on a piece of paper which was about 9 metres away. A divergence of about .99 mRad - that's an argon all right.

[mixedgas]

Your cavity optics are filthy, as evidenced from the transverse mode noise, but at those excellent power levels leave them alone.

ILTs are the toughest air cooled tubes, real works of art, lots of grain, and your results are typical of a low hours ILT. Set it up for 4 amps to 9 amps and be very happy. The cavity optics are dirty, but do not attempt to open them up at this current level of performance. ILTs are a bitch to realign, with inverted, sealed, optics mounts. Therefore leave the optics sealed and alone, but you can peak the fine adjusts which are near the optics mounts if installed(DO NOT TOUCH THE BIG COURSE Adjust screws) with tinsy tiny movements of a allen wrench.

ILTs optics train was intended to be sealed for a whole warranty life. No one intended that to be decades.

Can you put a grating on it? I'd like to know if it has a prism, all lines, or wavelength selective optics. If it has a prism, the rear fine vertical (if installed) selects wavelength. The fine trim is a flexure, not a MM style adjust, so tinsy tiny adjustments.

BTW< consider bolting it down to some aluminum, if the baseplate is getting warm.

It looks like the light pickoff beam splitter is filthy too. That you can clean.

Steve

[Stoney3K]

Your cavity optics are filthy, as evidenced from the transverse mode noise, but at those excellent power levels leave them alone.

ILTs are the toughest air cooled tubes, real works of art, lots of grain, and your results are typical of a low hours ILT. Set it up for 4 amps to 9 amps and be very happy. The cavity optics are dirty, but do not attempt to open them up at this current level of performance. ILTs are a bitch to realign, with inverted, sealed, optics mounts. Therefore leave the optics sealed and alone, but you can peak the fine adjusts which are near the optics mounts if installed(DO NOT TOUCH THE BIG COURSE Adjust screws) with tinsy tiny movements of a allen wrench.

I'm not going to bother with opening it up and cleaning or otherwise adjusting the optics. The thing is already running way over spec as it is now, so I would be foolish to try and 'tweak' everything for super power, complete TEM00 perfect beam. I'm planning to use it for my laser harp, so I'm more than happy with a little more powerful, multimode beam.

I set the idle current at 6 amps for now, I tried running it at 4 but it wouldn't remain stable, as I kept seeing the tube wash out and restart when it hit just under 4 amps. (I know it was not running under threshold as I heard the igniter every time)

Can you put a grating on it? I'd like to know if it has a prism, all lines, or wavelength selective optics. If it has a prism, the rear fine vertical (if installed) selects wavelength. The fine trim is a flexure, not a MM style adjust, so tinsy tiny adjustments.

Already way ahead of you.



Lasing on 6 lines as it says on the tin!

BTW< consider bolting it down to some aluminum, if the baseplate is getting warm.

It looks like the light pickoff beam splitter is filthy too. That you can clean.

I can imagine it would be filthy, since it's been sitting in the old housing collecting dust with nobody bothering to put the cap on it for transport. Nothing a good bit of spit 'n' polish wouldn't fix, would a simple alcohol swab be good enough for the front of the pickup? I'm not sure if it has any special coating on it.

The rest of the unit is in need of a bit of a cleaning as well. The outer casing should be no problem, and I'm going to leave the heat sink alone for now since it would be too much of a hassle to open the lot up. The air coming out of the blow-hole at the top is warm, but not surprisingly hot.

The other thing to do is fix some cosmetics, like ordering the proper connector backshells and fixing that ugly hack on the PSU. I guess I'll take artistic liberty and cheat a bit, by putting back the key switch and adding a 3-pin XLR underneath which would be a 'remote interlock'. If I can find a good 6-12V DC supply inside the PSU I can leave it out altogether, but I need some DC juice to power the relay board that has been bodged inside of the unit. The added bonus would be that I have a proper modulation jack to control the tube current from the outside if I want. (The current control is too slow for blanking, so I wouldn't bother with that, but it's perfect as a dimmer.)

BTW, tube voltage is 104V at 9 amps on cold start and climbed to 106,6V after a 10 minute warmup. Filament voltage is 2,65VAC. (Right on the money, if you ask me.)

[mixedgas]

BTW, tube voltage is 104V at 9 amps on cold start and climbed to 106,6V after a 10 minute warmup. Filament voltage is 2,65VAC. (Right on the money, if you ask me.)[/QUOTE]

2.65Vac is Right on the money for a standard 5 turn cathode. You can pop the light sensor apart and clean the AR coated pickoff disk with a swab and alcohol. The solar cell leads are a bit small, so be careful. Note the direction that the disk is installed, some times it matters.

Perhaps one of the reasons ILT as a company failed early, besides some wild investments in laser driven dental whitening that was quickly surpassed by whitening that did not need blue light, was that they made too "good" a product and their tubes always exceeded spec and did not fail fast enough. Other ion companies made the money on the replacement tubes. The biology companies loved ILT for this. The tubes would last a long, long time.

Be careful, most ion PSUs have a high side and a isolated low side, and the high side will be at line potential.Both sides will have +/- 12 or +/- 15V sources. So you must choose your 12V source carefully. I'd call DZ and see if they would tell you where to get it off the PSU interface. Or use a external source.

6A is not worrisome, you have a bigger tube then you think. ~106V is about right for a 110VAC laser.

Enjoy it.

Steve

Steve

[absolom7691]

ILT heads bear a striking resemblence to the 60X heads (from the looks of it). Or is it the other way around?

[mixedgas]

Specific heads were developed for various end users. Other users copied the form/fit/function to compete for contracts.
Some times the only thing that changed was the baseplate mounting hole pattern.

60X is Xerox Photoprinter. (room sized high speed printer, prints a whole book in a minute or so)

60B is Hell Typesetter, which is where the side fans come from.

Omni532 is a 60X form factor clone.

NECs heads were SP161 clones for the most part.

I'm somewhat sure ALC predates ILT.

At one time there were at least 4 air cooled laser manufacturers in Salt Lake City, alone, all ALC or ALC spinoffs.

HGM and ALC were both owned by Laser Corporation, same tube designers, one line is medical, other production line was OEM/Scientific.

Steve

[absolom7691]

One of my first lasers was an ALC 60X. I loved it. It was a snap to service and realign. We broke down a ton of those at MWK. Took out the single-line, single-mode optics and put in some 60cm optics and got 180mW+ with 9 lines. I miss the old ion days. I also used to live about 5 miles away from Omnichrome in Chino, CA

[Stoney3K]

OK, it was about time the PSU got a little TLC and I un-hacked the modification done by Datronik.



There was a pretty straightforward mod in there which consisted of a relay (tripping the interlock circuit and replacing the key switch) and a simple wire which overrides the current control on the upper PCB. The wire pair which does the 'modulation' was connected to the terminal block next to the capacitor bank.

The fix was simple: Remove relay, and replace key switch in the proper circuit.



The end result, happily running at a set current. Instead of fidlling with PSU's, I can just plug the unit into the wall and turn the key for some coherent fun.

Right now I set the current for about 8,5A and a resulting power of 250mW. Should be more than enough for what I want to do with it.



The front of the PSU as it is now. It's still in need of some spit 'n' polish, as the key switch is slightly smaller than the DIN plug which was hacked into the housing and left a few holes where they should not be.

Furthermore, the head is missing a few screws and one of the PSU screws has been damaged. So there's still some cosmetic work to do here, but I need to order some components for that. (Also, end caps for the Amphenol jacks and back shells for the plugs)

Does anyone have information on which connector should mate with the original interlock jack? Right now it's populated with the factory supplied jumper.

I might put back the modulation wires and reroute them to a proper BNC jack, but I don't need it right now.