Questions about a JHE beam table laser projector.

[m2b]

Next is the complete unit.

Then with the lasers operational.

A shot of the area with the missing half silvered mirror.

I went to the "One Stop Laser Shop" and found the Dichro that I need (Thanks again Steve). I will hold off buying it until I'm sure I can get the rest of the system up and working.

[m2b]

A shot of the connectors that attach to the unit.

There are two sets of female RCA plugs with a gray and a black wire in each set. The gray wire is marked with an X on one set and a Y on the other. I will check and see where these wires go but my guess is the associated black wire goes to the corresponding blanking flag amplifier. My question is where do these connect? Directly to the tape player, or more probably the FM modem box? Does anyone have any idea as to the proper connection sequence? The connector on the far left appears to supply a wire from each of the three pins to each of the individual amp boards so I'm guessing that it is the main power supply plug. I will trace down where each of these goes.

A cu of one of the connectors.

There are three identical three pin connectors. I will probably need to trace down where they go on the amplifier boards unless one of you has any idea of that they are for. I fairly sure (and two of you have confirmed) that one is a +- DC supply. The other two will need tracing probably to get some idea of what the do.

[m2b]

The front of the FM modem box.

Only you guys know what all this means and I would be very happy to understand it all.

cu of XY controls on front panel.

cu of RG controls on front panel.

Picture of connectors on the back of the FM modem box.

I have no idea what goes where except that wires come from the tape player and other wires go to the laser amp boards. Any educated guesses out there?

[mixedgas]

I just drove 724 miles today, back home. I'll get back to you in the morning when I'm awake again.
Nothing I see there is rocket science, hookup wise. I think you have everything you need except power supplies. Marlin P. Jones Inc sells some inexpensive ones.

The amps are Gen II G120 amp clones. However he changed the layout and the edge connector. The pinout will be easy for me to reverse engineer.

We can work out the power wiring by tracing the LM1458 pins with a ohm-meter , for example.

I'll post tomorrow some time.

All I see there is 4 amps needing power and RCA single ended inputs to the amp... Piece of cake.. given enough time.

The FM demod is a clone of a LFI mod/demod... Again, no issues.

Take a pic of the demod for me with the lid off please... Just for grins and giggles... See if there are any chips with a 9400 in the part number?

Steve

[m2b]

Hi Steve,

Here are some pictures of the inside of the demod box as requested.

The entire box.

The set of two cards stacked two high.

Note that there are two cards stacked one on top of the other. All of the cards appear identical except some of the caps are physically larger due to a larger working voltage. I think a case of what parts were in stock at the time.

A close up view of one of the cards.

All of the small eight pin chips are labeled: GL4558/NO6R0K

The 16 pin chip is labeled: 2206CP/9226

The 14 pin chip is labeled: SM9048/LM565CN

Remember, I know nothing....what's up with a 9400 chip???

Me Bad, The boards appear identical but the small 8 pin chips on the R G boards are different: LM1458N/M9201

[m2b]

I did some power wire tracing and have the following results.

Each connector contains three pins which I will label 1-2-3 starting from the end with the "V" point on the plastic housing.

The first connector "A" pin 1 connects to edge connector 22 on the back of both the X and Y boards. Pin 2 connects to edge connector 14 on both the front and back of the board. Pin 3 connects to edge connector 13 on both the front and back of the board. Pin one appears to be the ground connector.

Connector "B" pin 1 connects to edge connector 22 on the back of both the Red blanking and Green blanking boards as well as pin 1 of the "C" connector. Pin 2 of the "B" connector attaches to both front and back of the edge connector at pin 14 of the Red blanking board. Pin 3 to edge connector 13 both front and back of the Red blanking board.

Connector "C" pin 2 goes to edge connector 14 both front and back of the Green blanking board. Pin 3 goes to edge connector 13 both front and back of the Green blanking board.

Thus it appears that the original design had a power supply for the X and Y drive boards, but a separate power supplies for both the Red blanking and Green blanking boards. Or perhaps there was an external switch so the the red and green blanking boards could be turned off independently of the X and Y boards. I'm not at all sure of the reason for this as I would imagine that one would want all of the boards working all of the time ans so why not have just one power supply for all four.

As long as I was tracing I checked out the female RCA pin jacks as well. As I mentioned before there are two sets of black and gray plugs. One marked "X" and the other "Y". The "X" center gray is connected to edge connector 18 on front of the green blanking board. The "X" center black is connected to edge connector 18 on front of the red blanking board. The shield of both to the ground on card connector pin 22 on back of both boards.

The "Y" center gray is connected to edge connector 18 on front of the "Y" board. The "Y" center black is connected to edge connector 18 on front of the "X" board. The shield of both to the ground on card connector pin 22 on back of both boards.

Some of the wiring follows logically and some does not, but then I may be missing something.

I am now going to check out the various tracks on the adat machine to see what is where. Is there any particular signature I should look for for the various tracks? Are you saying that JHE used his own proprietary assignment of tracks (Left Audio, X1, Y1, Color1, X2, Y2, Color2, Right Audio) rather then the ILDA Standard track assignments Dave described, (X, Y, R, G, nothing, SMPTE, L Audio, R Audio)?

[mixedgas]

Ok, I have looked at the pics.

Xr2206 is used as the FM VCO, LM565 is the decoder. Instead of using the 9400, which is a one chip solution for both. The dual opamps are the same, one is a house marked part. I'm not shocked he did it that way. Those chips used to be very inexpensive compared to a 9400.

OK, you know what ground is on the amps. Now we need to find V+ and V- for the amps.

The attached drawing is a LM1458 Opamp, note the orientation notch... On some chips this notch may be replaced by a dot over pin one. PIN FOUR on the opamp will connect to the Negative (VSS) psu rail.. Pin EIGHT On the Opamp is the Positive (VCC) rail. It would be easiest to trace them with a voltmeter set to Ohms. One 1458 pin will go to edge card connector pin 13, the other to edge card connector pin 14. Its up to you to trace the two out.


Whom-ever did the layout was cute about it and hid the traces under the sockets, without direct traces. So I can't easily follow this without un-socketing the chip or spinning the board around. So you'll have to do a little tracing yourself.

LM1458 is limited to a +/- 15 volt supply. So you need +/- 12 volt supplies. He split the blanking amps from the scan head amps to keep power jumps and spikes from the blanking galvos out of the images.

I added a pic of how to interpret the FM decoder from what I can see.

So you can do four of these :

http://www.mpja.com/12V-85A-100W-Pow...info/16013+PS/ Puts out 12 volts, 8.5 amps. Two for the Scan axis and Two for the blanking.

Get four (these or similar of at least 10,000 uF) 33,000UF 50V COMPUTER GRADE CAPACITOR from All Electronics, to handle the surges that G120s generate. http://www.allelectronics.com/make-a...PACITOR/1.html

Steve

[m2b]

Great information, thanks again Steve.

So now we know that 14 is negative and 13 is positive.

I'm wondering if you see any problem in using these power supplies as I plan on mounting them all is a sub chassis under the unit and I could save a few bucks.


http://www.mpja.com/12V-17A-Phihong-Power-Supply/productinfo/18091+PS/

Also thanks on the FM decoder information. If there is anything else I could send you to help solidify your interpretation, just ask.

It is interesting to note that some of the plugs are used for actually encoding shows. Not that I'll ever be ready to do any such thing...but never say never. How complicated a thing is it to do?

[m2b]

Did some playing with the tapes I guess they are indeed clones from a previous life. Audio is on tracks 1 and 2. Tracks 3-6 contain the control tracks. Is there any way to tell what is what? I would imagine the X&Y tracks would look somewhat similar but hopefully different from the red and green tracks. Any hints on what I should look for?

[mixedgas]

Did some playing with the tapes I guess they are indeed clones from a previous life. Audio is on tracks 1 and 2. Tracks 3-6 contain the control tracks. Is there any way to tell what is what? I would imagine the X&Y tracks would look somewhat similar but hopefully different from the red and green tracks. Any hints on what I should look for?

Phihong = often problematic... Early generation units, and they never improved. I've replaced more of that brand then I care to remember. They often take their loads with them when they expire. Those need external fans. However, if cost is a issue, those will work if you put in the surge caps.

OK, X-Y signals will swing both ways if you have a oscilloscope. Blanking signals will usually only swing one one way, be square waves or ramps, and have a DC offset. If your scope has X-Y mode you can see the graphics.

If you dont have access to a o'scope:
If you hook up a 10K potentiometer (Radio Shack) as a attenuator, you can use some of the sound card oscilloscope programs to look at your signals.
Keep the signal to the sound card below 300 mV. Ie RCA jack from ADAT to the potentiometer. Then run a 3.5 mm plug off the potentiometer wiper.

I sent Karl a scope long ago, if you feel the need to get ahead.

I think you may want to put some potentiometers for image size between the galvo amps and the decoder outputs. 1K or 10K will work just fine. The amplitude potentiometer on the galvo board is used to set the master size, never for show to show adjustments.

If you ever need to record shows, you can possibly DC mod the ADAT (If its not already modded) and skip the encoder/decoder. This has far better results then using a noisy encoder. Which ADAT model do you have? Some can't be modded....

Steve