Rebuilding my old analog console

[laserist]

An analog multiplyer multiplies two voltages (and divides by 10 to keep the output from hitting the rails). So if you have your image's x axis at one input to the multiplier and a 0-10 ramp at the other input the output will be your image where the gain follows the ramp voltage.

[laserist]

This might help put things together:



the dashed line divides the upper and lower card cages. There was a row of four three position leverlite switches which selected the lower (hybrid) cage - the upper cage - or summed the two together. The color key is debatable.



The lower (hybrid) card cage block diagram. This is where the data channel and the image data it interacted with lived. The upper card cage is where total override, colormod, chopper, clipping, joystick, etc lived...

[Kevint]

My bad, I misinterpreted the 2QMM schematic. I thought it was the internals of the AD533, not how to build one. Now I see.

Thanks for explaining how the multiplier works. After reading that I searched for more info on how multiplier work. Thanks for keeping it simple - I'm at electric technician level or maybe senior electric tech level.

The drawings are very helpful to see how things are put together. The original Laser Image one is awesome and done back in 1977 when I was 13 years old. That's too cool.

[Kevint]

Ok. Breaking this discussion section down into 2 parts. 1) electronics to select various image inputs, and 2) a multiplier to vary the image gain. Putting item 1 aside, what would be the best modern day way to do number 2.

Options:
AD533 - still some available, a little expensive
Or ???

I did find these during my searches:
AD633 available and inexpensive
THAT Corporation 2080 VCA, available good pice
THAT Corporation 2062 Dual VCA, available good price

Would any of these options work?

[laserist]

If that is the prototype you gave me, I have it packed as it was sent. I'm not likely to need or use it, as all that functionality was moved to software in my system. I'll pay the shipping to send it back to you or to anyone who you think should have it, if anyone wants it. It comes with hand drafted docs that are a marvel of technical discipline compared to the schematics and wiring diagrams I draw. Include fine motor skills in the many of your attributes I'm in awe of. By the way I just got a lode of Mark 4 schematics and docs, and further information on the SAGE and other topics. How fortunate the most interesting people I can imaging talking with tend to be so generous with their time and knowledge.

If you'll never use it - sure send it back - it'll be fun to finish it. Retirement is just 55 weeks away... I should have some free time?!

I was thinking a couple of weeks ago that somebody created a not for profit "Friends of the McDonnell Planetarium" organization more than a half century ago, and maybe it's time to create a for purpose "Geeks of the McDonnell Planetarium" organization. Or something...

[laserist]

Ok. Breaking this discussion section down into 2 parts. 1) electronics to select various image inputs, and 2) a multiplier to vary the image gain. Putting item 1 aside, what would be the best modern day way to do number 2.

Options:
AD533 - still some available, a little expensive
Or ???

I did find these during my searches:
AD633 available and inexpensive
THAT Corporation 2080 VCA, available good pice
THAT Corporation 2062 Dual VCA, available good price

Would any of these options work?

I'm sorry, have I been typing 533? - not just no, but hell no - they needed trimpots. The AD633ANZ is what you want...

[mixedgas]

Make sure you buy the 633 from a reputable US vendor or the factory. The Ebay overseas fakes are notoriously bad. I know, I received junk that was labeled AD633, but had poor quality RC4200 (Obsolete) dice in them. I'm not the only one who was "Burned".

Fakes:

https://www.electro-tech-online.com/...nected.163888/

https://youtu.be/W0YRIjx8fjk?t=159

Steve

[Kevint]

Mixedgas: sorry to hear about the fakes and thanks for the heads-up. I will buy from Mouser or digikey.

[Kevint]

Mixedgas: sorry to hear about the fakes and thanks for the heads-up. I will buy from Mouser or digikey.

[laserist]

Newark had a good price when I looked...