Re: [arcade] rotating monitors frequently (fwd)

Jeff Anderson wrote:

> >
> > You'll see my version of a raster cabinet with a easily rotatable monitor :-).
> > It's a 25" monitor. If the game has been off for a good amount of time (maybe
> > 20+ minutes), I can rotate the monitor in any direction, and the colors will be
> > fine.
> >
> > However, if I go from playing a Horizontal game to a vertical game, as I turn
> > the monitor, the colors will change. By using a degausing coil, I can fix 90%
> > of the monitors color in about 15 seconds, but for some reason the upper right
> > corner (which would be the lower right corner in horizontal mode) remains
> > unchanged :-\. Of course, if I turn the game off and turn it on a few hours
> > later, the corner color is fine again.
>
> There is a really easy way around the problem of having to wait for a
> monitor to "straighten itself out" by letting it sit for a while.. The
> reason you have to wait is because the PTC is cooling down. Just short it
> out and put a switch inline with the degaussing coil (DGC). Whenever you
> want to DG just press the button for about 3 seconds. DGing doesn't hurt
> the monitor, just dont hold the button down for a few minutes or you may
> see smoke.
>
> the PTC (positive Temperature coefficient) is basically a resistor that
> limits current flow when it heats up. When the monitor is cold the PTC
> passes current to the DGC, and after a few seconds it heats up and cuts
> the current off. It will "trickle" enough to keep it warm (and thus the
> DGC off) whenever the monitor is on. it usually takes at least 10 min
> for the PTC to cool off enought to do a complete DG. The PTC is that
> little black box with 3 pins on the monitor chassis, usually right next to
> the DGC connector..
>
> Jeff

There is a small problem with that. The PTC doesn't just turn off
the coil, it SLOWLY turns off the coil. A sudden turn off via a
switch will actually magnetize the tube. Beautiful to see but a bear
to do anything useful with.

Some monitors have a push-to-degauss switch and one of these
could be added to your monitor. When not pressed it should
remove ALL power to the degauss circuit. This keep the PTC
cold and ready to go. Press (and hold) the switch for about 5
seconds to apply (and slowly remove, via the PTC) power to the
entire degaussing circuit. Some computer monitors, Nintendo
monitors, and other (foreign) monitors have this arrangement.
Received on Wed Jul 14 01:42:02 1999