Re: multi-game proto board

At 02:41 PM 5/2/97 -0700, you wrote:
>
>well, it looks like the sound part of it is still up in the air, so
>what about a board with just the bank switched ROM, 4 player input
>mux, level converters for a WG monitor, with adr/data buffering
>and a couple of 22V10's wired up for io and adr decoding, then a
>big wire wrap area to prototype the sound hardware? Bring out the
>adr/data and strobes to vias so they're easy to get to. That way,
>if you didn't want to mess with the sound at all you could bank
>switch the existing sound cards with a single wire over to this
>card which would replace the EPROM board.

Excellect idea, now your onto to something I'd *really* like to have.

There is just one thing though. The difference between the Sega monitors
and WG is more than just level shifting. The Sega monitor is capable of a
faster vector sweep rate. The WG will not be able to keep up with Sega
vector generator. I haven't tried this but my guess is that in order to see
a non-distorted picture, your going to end up with a shrunkin image centered
on the WG. You won't be able to compensate for this with signal
amplification since the problem is in how fast you can "charge" the
inductance of the yoke.

The only way move the beam faster is to increase the maximum allowable yoke
currents. Assuming the Yoke inductance remains constant, you must drive it
with higher X/Y voltages. Which is why the Sega monitor needs +/- 50 volts
while the WG monitor only uses +/-25. It's also why Sega monitors are so
flamable.

The fix for a WG would be a little involved, but not a lot. I would suggest
parallelled transistors to handle the higher wattages (as opposed to the fan
thingy). But mostly it would be changing values here and there to handle
the higher +/- 50 volts. Since it would still be able to handle the slower
Atari speeds the "upgraded" WG should still work with the Atari (and in the
case of Boxing Bugs and War of the Worlds, Cinematronics) games.

-Zonn
Received on Fri May 2 15:08:00 1997