Questions about a JHE beam table laser projector.

[m2b]

Hi all, I'm new here and just became the owner of a possibly useful JHE beam table laser projector. I say possibly useful because I'm sure some of the parts are missing and some broken so I need to find out what they are to get this system up and working. I was happy to see that both lasers came up and are working. I must admit that I didn't think the green one was any good as it took a few minutes to ignite. Perhaps that is something that will need work later.

First thing that I need to find is a power supply for the driver cards. It kind of looks like a simple computer supply would plug right in. Before I start tracing wires and guessing as to what the power requirements are, I thought that maybe one of you fine people might know or have schematics of this unit and help me get through.

There are four cards labeled LSDC with a logo of AGCD (I believe) with a number of 53005. If anyone has any idea of who the manufacturer is perhaps I could find some information on the web. There are four cards: one for X, one for Y, one for red blanking, and the last one for green blanking. They all appear identical at first glance.

There is also one mirror missing. I'm not at all sure, but it looks like it need to be of the half silvered variety. It looks like the green laser is reflected around to the back of this missing mirror and then in to the reflecting servo mirrors. The red laser would appear to reflect off the front and then into the same mirror.

The programs are on ADAT 8 track tapes. I believe four tracks for the audio program and four that run a controller box which then feed the the four cards.

I am in the process of building a planetarium to which I believe this would be a nice addition. If anyone can help me get this system working properly again I would be most appreciative.

Ron

[mixedgas]

LSDC = Laser Systems Development Corp.
That company is Long Gone...

Steve

[DZ]

Hi all, I'm new here and just became the owner of a possibly useful JHE beam table laser projector. I say possibly useful because I'm sure some of the parts are missing and some broken so I need to find out what they are to get this system up and working. I was happy to see that both lasers came up and are working. I must admit that I didn't think the green one was any good as it took a few minutes to ignite. Perhaps that is something that will need work later.

First thing that I need to find is a power supply for the driver cards. It kind of looks like a simple computer supply would plug right in. Before I start tracing wires and guessing as to what the power requirements are, I thought that maybe one of you fine people might know or have schematics of this unit and help me get through.

There are four cards labeled LSDC with a logo of AGCD (I believe) with a number of 53005. If anyone has any idea of who the manufacturer is perhaps I could find some information on the web. There are four cards: one for X, one for Y, one for red blanking, and the last one for green blanking. They all appear identical at first glance.

There is also one mirror missing. I'm not at all sure, but it looks like it need to be of the half silvered variety. It looks like the green laser is reflected around to the back of this missing mirror and then in to the reflecting servo mirrors. The red laser would appear to reflect off the front and then into the same mirror.

The programs are on ADAT 8 track tapes. I believe four tracks for the audio program and four that run a controller box which then feed the the four cards.

I am in the process of building a planetarium to which I believe this would be a nice addition. If anyone can help me get this system working properly again I would be most appreciative.

Ron

I think those amps were only good to around 12K, I may have a schematic around here somewhere. I don't remember them being very difficult to tune though. I think it used a +/- 24VDC supply. It was a pretty basic rig, RYG, G-120 X/Y scanners and G-120 flag blanking. If I remember correctly the assignments for the adat were: X, Y, R, G, nothing, SMPTE, L Audio, R Audio. The SMPTE was used to time the ScreenMaster2 automation of slide projectors and special effects in the theater.

Joe is still around, I don't have his email at the moment, but you can dig him up on ebay, his ID is screenmaster2

[m2b]

Thank You Steve. There does seem to be a Laser Systems Development Corp. in Ireland with an office in Colorado. It was established in 1975 and is still in business. It is interesting that they did or do make small projectors for planetariums.

[m2b]

I think those amps were only good to around 12K, I may have a schematic around here somewhere. I don't remember them being very difficult to tune though. I think it used a +/- 24VDC supply. It was a pretty basic rig, RYG, G-120 X/Y scanners and G-120 flag blanking. If I remember correctly the assignments for the adat were: X, Y, R, G, nothing, SMPTE, L Audio, R Audio. The SMPTE was used to time the ScreenMaster2 automation of slide projectors and special effects in the theater.

Joe is still around, I don't have his email at the moment, but you can dig him up on ebay, his ID is screenmaster2

Thank You DZ. I am new at this so forgive my ignorance. I'm guessing your saying that the boards I'm inquiring about are amplifiers for the servo units that vibrate the mirrors and they will not vibrate at a frequency higher then 12K. I have no idea of what is involved with tuning or what it even is. Remember your dealing with someone who has never worked with anything like this before.

There is another box called an "FM Modem" that has 16 RCA type jacks on it which I assume is wired between the adat and the laser assembly. There are three, three pin malox connectors which are for power or perhaps a remote switch of some kind. One of the three connects to all four boards so I'm guessing that is the +/- 24 VDC supply line. I'll need to trace these wires down to get some kind of an idea as to where they go.

The G-120's as you call them have a literal flag that turns in front of the laser beams to cut them off.

Looking at Joe's web site, there is a virtually identical unit listed for $5K. I will play a tape to check but I'm guessing your track assignments will be accurate.

Any info that you can come up with would be greatly appreciated.

[daction]

Oh yeh,
Any chance of some pictures. Sounds like come choice wiring.

[mixedgas]

12K pps translates to ~ 1400 Hz max response. The best you get out of a typical FM encoder/decoder is usually 1-2 Khz of bandwidth anyways. I'd guess some one transposed very old 1/2" 8 Track FM tape to the newer ADAT when the 1/2" tape machine was getting hard to maintain. The amps he used for G120 and G138 galvos are, as Dave said, slow and hard to tune. I have a large amount of his gear, and he tended to use very large mirrors that have lots of excess inertia compared to more modern convention. This leads to flicker as scan angles increase, or as image complexity increases.

Usually FM was used for a two scan head system, with the audio on the outer tape channels for least noise, so you may also find you have Left Aud,X1,Y1,Color1,X2,Y2,Color2,RHT Aud, instead of the ILDA Standard assignments Dave described.

My collection of FM tapes (from more then one vendor) are aud,xy,blue,xy,red,aud.

I would strongly suggest that you identify the signals with a oscilloscope in X-Y mode. If you have no means of reducing the image size with knobs in the existing system, you need to add potentiometers between the decoder and the scan amps. Some of the early amps were very prone to oscillation which can damage the scanners. A good way to induce the oscillation is to overdrive the amps.

The amps have to be tuned, that is the servo loops matched to a given scanner-amp/mirror combination. If you have what I think you have, you may just have offset, size (angle), servo and damping. 2nd Gen amps usually have a PID loop with more pots to adjust. Those amps you have are matched to a given galvo and mirror during tuning.

A second caveat with early G120s, DONT use the offset on the amp boards to position the image. Its really there for correcting the sensor errors in the galvo. You can use the offset on the front of the decoder if its there. There should be one set of knobs for overlapping the images.

That generation of amps needed typically +/-12 to +/-15V and often some other lessor voltages. LSD-CO used a card bus structure, and not the standard GSI pinouts..

I long ago tossed out the catalog.

I need a picture of the amp to see what you may have.

Your missing optic is called a Dichro, short for Dichroic beam combiner. Its about 20-30$ to replace one. For what you need, I'd suggest One Stop Laser Shop near Tampa. Sounds like your talking about a "pass green reflect red" at 45 degrees.

For years, LSD_CO has been off the searchable net. I guess he's back.


Steve

[m2b]

Thanks again Steve.

I will get some pictures up ASAP. Also look for that mirror.

[SpitzSTP]

Thanks again Steve.

I will get some pictures up ASAP. Also look for that mirror.

Is it possible to get the pinouts for these old LSDC boards? Anybody have?

[m2b]

I have taken a few pictures that I hope will help.

The first two are the front and back of the amplifier/driver board.

Perhaps someone can identify these boards.