Re: Protecting XY monitors...

At 02:35 PM 9/5/97 -0500, you wrote:
>On Thu, 04 Sep 1997 23:42:01 -0700 John Robertson <pinball@istar.ca>
>writes:
>
>>It seems to me that the real problem with these poor monitors is if
>>the power supply of the game board goes bad that the
>>monitor gets lonesome and dies. Now in the interest of keeping them
>>from croaking how about a simple little relay circuit that
>>cuts the power to the monitor if the +5 supply goes outside a set of
>>parameters AND/OR if the logic board locks up? I was
>>thinking along the lines of a watchdog reset monitor circuit, or just
>>a simple circuit that monitors the X and Y outputs and
>>if the signal doesn't change enough over a certain period of time that
>>the power is cut to the monitor. This could be self
>>restarting so if the problem is an intermittent one can "play" the
>>game around the problem...Well, any other bright ideas???
>
>How about this...
>(no actual circuit descriptions, just ideas...)

This is not a bad idea, WG and Amplifone both tried different ways of doing
this. Amplifones worked the nicest, WG's just screwed up Tempest causing it
to colapse between player one and player two modes.

>Since most of us have seen a color XY (or two) with the phosphor @ 0,0
>burned away, how about something to prevent this? I've only seen
>descriptions of what the display looks like with this fault. I believe it
>has to do with the Z being stuck on for one of the RGB channels allowing
>the e- beam to blast 0,0 with the full intensity beam.

I'll bet it's do to some idiot accidently turning up the brightness for a
split second. Some total jerk playing with the brightness control without
looking at the screen the whole time he's tweaking the control. Some
complete loser playing with the brightness control not realizing how bright
he's driving the display because he's sitting behind the monitor instead of
looking over the top of it while he's adjusting the knob -- Well at least
that's how I burnt out the center pixel of my display.

-Zonn
Received on Fri Sep 5 15:40:48 1997