Re: Major Havoc -> Tempest Adapter Schematic

At 11:04 AM 9/2/97 -0800, you wrote:
>>Could someone scan in the schematic for the adapter board
>>to put a Major Havoc into a Tempest? I've noticed there are
>>subtle tweeks to the multiplier values for the different
>>game implementations, and was wondering if this circuit was
>>identical to that on a Tempest.
>
>I've got a few variations on this if Jess doesn't get around to it.
>
>It's very close to Tempest. I think it's almost identical-- it's been a
>while since I tinkered with it. I actually have it breadboarded up and
>running, but with other projects always getting in the queue...
>
>>Also, does anyone have any opinions why the Quantum PCB
>>HAS the XY correction circuit, when it shipped with an
>>Ampliphone monitor?
>
>Beats me. Did Atari actually populate it? (Haven't seen a real Quantum
board.)
>
>On another note... Have any of you tried removing the VDR's from the
>output section of the AVG and seen the effect it has on the display? I did
>this on a Space Duel and couldn't notice the difference-- however, I was
>only running it on a scope, which masks a LOT of little details compared to
>the big monitors.

The problem with the scope is that it doesn't have the non-linearities of
the CRT (wouldn't be much of a scope if it did!) so things should actually
look better without the VDR's on a scope.

It's similar to looking at the output of a Tempest on a scope. Looks ok on
a WG monitor, but on a scope you see all the bowing of the edges used to
compensate for the pincussioning of the WG monitor.

>Does the VDR prevent some blooming as the deflection gets larger? (I'm
>trying to remember Al's IE curve from last week.) Anyone know where to get
>VDR's like those that Atari used? My quick search through Newark came up
>empty. Maybe EE Master has a source...

According to a technition working at Cinematronics at the time, they
couldn't find them either which is why they designed around them (using an
op-amp of course!) I haven't traced out the circuit so I don't know what
they did.
>
>Related topic-- anyone have the tube characteristics for the CRT used in
>the WG vector monitor (I think it's the same as the GO-7?). Stuff like
>heater voltage, gun voltages, screen and grid, etc.? I wonder if it might
>be possible to swap tubes with a modern 19-27" tube and keep the deflection
>yoke, but get the benefit the no curvature... Worst case I suppose it
>would require a new (or modified?) neck board and HV unit. Probably want
>to stay away from Sony tubes since the aperature grille would mess with
>vertical vectors, but some standard shadow mask type thing like a flat
>Panasonic or Toshiba would be neat. (Nice dark phosphor coat too...)

Alright Clay!!! Now we're talkin'!! This is one of my long term goals

(Just ask Steve O. -- I keep threatening to do this! Yes Steve, a laser
based system would be best, but how about colors? Talk about a convergence
nightmare! Not to mentions costs! ;^)

To have that new flat Panasonic display running vectors would be way cool!

I've gone through some of the same thoughts. Won't even touch a Trinitron.

I haven't popped off the back of my Panasonic TV to see if any yoke will
even slip over the neck. I'm guessing an Ampliphone yoke would give the
best results, since I'm assuming they've done away with the pincussioning
problem in the tube's design. Of course the opposite could be true, the
reason screens were round was to cut down on, mostly focusing problems, but
it would also help with the pincussioning. Maybe they just let it
pincussion all it wants and then designed around it in hardware.

Considering how flat the tube is, and how that was always a problem in the
past, I'm wondering if they've come up with some custom IC stuff to deal
with a possible non-linearities of a flat tube, that would be a drag. I'd
be willing to live with size changes throughout the screen, but my biggest
fear is how much trouble it's going to be to converge the thing!

Of course this is after figuring out how to use the power supply in the TV
to run the much higher HV voltage & focus, and surely higher plate voltages.
I was thinking that by simply removing the TV's yoke and leaving it hooked
up to the circuit (just tie wrap it off somewhere), you could leave the TV
running the standard *blue* screen it defaults to with no input, thereby
supplying all the HV voltages. Since the RGB transistors are running open
collector on the Amplifone (or WG) circuits maybe they could drive whatever
the voltages needed by the new CRT would be, or maybe the TV's RGB outputs
could be tapped into.

I haven't done *any* experiments with any of this, but it sure is a great idea!

-Zonn
Received on Tue Sep 2 11:39:02 1997