Re: Gravitar - Quantum control panel

On Thu, 29 Aug 2002, Mark Jenison wrote:
>
> Just FYI, if you want to keep it a Gravitar cabinet as well, you CAN play
> Quantum with the monitor in the horizontal position, and not have to play it
> sideways. With an adapter, you can switch the X and Y outputs and you will
> be able to view the screen correctly on a horizontally mounted monitor. The
> screen will be smaller and slightly squished, but it is entirely playable.
> Rick Schieve used to play his Quantum board out of his Black Widow cabinet
> this way.

I've done this too - had to cut/jumper the LF13201 analog switch on
the Quantum PCB to get the X invert and Y invert that I wanted.

I posted this to Vectorlist waaaay back when I first tried it:

http://www.arlo.net/vectorlist/archive/9912/0192.html

And once again, credit to Ray Ghanbari for the inspiration, over four
years before I tried it :)

http://groups.google.com/groups?oi=djq&selm=an_107601739

Basically, you swap pins 1 and 16 of the LF13201 to invert the
output for the desired axis. Exactly which axis you need/want
to flip depends on how you mounted your monitor.

(Cutting-and-pasting from the above links in case the archives ever go
away...)

On Wed Dec 08 1999, Doug Jefferys wrote:
> >
> > Quantum, running on a horizontally-mounted monitor. The good news
> > is that (for this monitor) swapping the X and Y outputs produces a
> > full picture. The bad news was that the X output (relative to the
> > horizontally-mounted monitor) was inverted right-to-left, and that
> > unlike Tempest, there are no XINVERT and YINVERT pins on the board
> > to tweak.
> >
> > According to the datasheet for the LF13201 analog switch (from the
> > spies.com archive) and the schematics for the board, it looks like
> > most, if not all, of the Atari games that use this chip in the AVG
> > section of the board are using it to control inversion. The axis-
> > inversion signal (and its inverse, from a nearby NOT gate) go to a
> > pair of switches on the LF13201; the configuration of the switches
> > determines whether the output signal is inverted or not.
> >
> > On Quantum, the signals controlling the switches are on pins 1 and
> > 16 of the LF13201s. Swapping these pins (cut two traces, solder a
> > pair of jumper wires crosswise) inverts (logically) the meaning of
> > the onboard X- or Y-invert signal, inverting (at the op-amp and on
> > the screen) the orientation of the video output.
> >
> > In my situation (rotated monitor and X/Y swapped), the two pins to
> > swap surfaced at two adjacent vias (thru-holes) near the three VRs
> > just above the AVG portion of the board, allowing me to stick a 2-
> > pin .100" connector into the board and "connectorize" the hack for
> > easy reversibility should I ever plug it into an original cabinet.

On August 6, 1995, Ray Ghanbari wrote:
> >
> > To invert the Y-Axis swap the connections to pins 1 and 16 of
> > the device at E10. For X do the same for the device at B10.
> >
> > My Major Havoc actually has the equivalent pins cut from the board and
> > jumpered to unused pins on the connector. If that board is put in a
> > cocktail cabinet, the orientation will no longer automatically flip for
> > player 2, but now you can use the external connector (or your adapter
> > harness) to do the proper inversions by using the +5V and Gnd pins as
> > appropriate.
> >
> > As always, check the schemtatics before commiting your board to the above
> > mods, and consider how crappy the display will look when you cram a
> > rotated horizontal display on a vertical monitor. For me, I prefer to
> > play them rotated rather than scrunched up

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Received on Thu Aug 29 10:26:51 2002