> On Feb 12, 2020, at 12:11 PM, David Speck MD <[email protected]> > wrote: > > Driving magnetic deflection coils at a high enough rate might prove to be a > problem. > Just some rambling thoughts...
The size of the tube is a major factor. I have an Atari Tempest video game (the real thing that you drop quarters into) with a color vector display. 19" CRT and magnetic deflection. Output transistors for the deflection amps are bog-standard NPNs in TO-3s. Well, that's true of the Wells-Gardner monitors at least. The original Atari monitors were OEM and used a custom HVT that was prone to failure and expensive to purchase from Atari. Most coin-ops switched them out for W-Gs and saved lots of money in the long run. Anyway, the game has a second PC board—a math coprocessor built from discrete SSI/MSI logic. I'm not certain but it was probably used for rotating lines (computing the square roots at least) and possibly calculating the slew rates for the vectors. Atari made several games like this. Tempest is by far the best of the lot (Star Wars is fun but too repetitive followed by too difficult). IIRC, Star Wars had an even bigger coprocessor board for heavy lifting as the graphics were wireframe 3D. Now my brain is all shook up. I can't remember half of this clearly anymore. I'm sure there are forums all over the 'net where all of it has been disassembled. The original games had all sorts of copy protection, possibly encrypted object code. What I do remember is that I paid $65 for it in 1992. I have a buyer lined up; I'm giving him a bargain price of $500. In it's present condition, perhaps with a little clean-up, it would go for a lot more on ebay. OK, back to the original topic... Terry Bowman, KA4HJH "The Mac Doctor" https://www.astarcloseup.com/ “The book said something astonishing, a very big thought. It said that the stars were suns, only very far away. The Sun was a star, but close up.”—Carl Sagan, Cosmos, 1980 -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/F17F1149-BA1D-49B7-9681-140DDE6AF61C%40gmail.com.
