8mm Forum: GS1200 Puzzle

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Posted by Paul Adsett (Member # 25) on November 08, 2019, 11:05 AM:

I have two GS1200's, a version one and a version 2, both acquired off ebay. I have noted that my version 1 machine has an extra circuit board which is not present in the later version 2 machine. This board is located next to the motor governor board and close to the back ESS panel.It sticks up vertically and is held by a single screw bolted to the metal bracket on the main control board. The question is what is it, what does it do, is this an Elmo board that was present in all version 1 machines, or is it some kind of add-on by the previous owner of the machine? Is it perhaps some kind of syc-pulse device?

Posted by Steve Klare (Member # 12) on November 08, 2019, 11:16 AM:

Oh, that's vector board.

-same stuff I use for my own mad-science projects!

The fun part of it is I have no real feel for how much room a circuit will take by the time I build it and then fix the problems, so I build on a big piece, find a case it will fit inside and just lop off the spare real estate when I'm done.

Posted by Paul Adsett (Member # 25) on November 08, 2019, 11:21 AM:

Yes that is the regular motor board that is present in both versions of the GS1200. Its the other board, the one sticking up vertically, that I am questioning.

Posted by Steve Klare (Member # 12) on November 08, 2019, 11:25 AM:

Sorry, Paul!

I first recognized the motor control and then re-edited when I realized what you were really talking about!

Interesting how the mounting brackets look like bare aluminum, but all of Elmo's sheet metal parts look plated.

Posted by Paul Adsett (Member # 25) on November 08, 2019, 11:32 AM:

I think your correct Steve, the more I look at it the less it seems like a production item! [Big Grin]

Whatever it is, it does not affect the normal running of the machine.

Posted by Steve Klare (Member # 12) on November 08, 2019, 11:39 AM:

I can't see where it connects to anything else!

(Does it?)

This could be someone's great idea that just didn't pan out! (I have several of these assemblies of my own! Every so often I need a part...)

Posted by Paul Adsett (Member # 25) on November 08, 2019, 12:03 PM:

It connects over to the pulse input socket on the back of the machine so I'm beginning to think that it might be something like a built-in Pedro or Renzo box, for synching to a DVD player. Or maybe it is a built-in pulse generator. But I have no idea how to use it.

Posted by Phil Murat (Member # 5148) on November 09, 2019, 04:06 AM:

Hi Paul,
This prototype board showing few components could be a small signal amplifier as well (10k trimmer is gain adjustment in this case)
I don't think this is a signal generator, however to be confirm.
How is powered this board ?

Posted by Thomas Knappstein (Member # 6134) on November 10, 2019, 11:36 AM:

Hi Paul!
Pic this Board out of the Machine and make a better
Photo of all Parts on it.

Posted by Steve Klare (Member # 12) on November 10, 2019, 01:00 PM:

I'm up to two (maybe three) small transistors, a bunch of resistors, some capacitors and a big potentiometer!

Whatever it does, it's pretty simple.

Posted by Paul Adsett (Member # 25) on November 13, 2019, 10:01 AM:

Here is a close up picture showing all the components on the board. All the wires from the board connect to the ESS/PULSE REC DIN socket on the back panel of the projector:

Posted by Thomas Knappstein (Member # 6134) on November 13, 2019, 10:48 AM:

Perhaps it could change a Fbas Video Signal to a TTL Impulse for driving the GS directly with a DVD Player or VHS Recorder.

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