Re: Mystery PCB

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I've never seen that board before, I suspect it has nothing to do with the
games business. Piezo switches just hook directly to the switch matrix. You
can even replace a piezo with a standard blade switch and a diode.

John :-#)#

At 03:55 AM 12/15/01 -0600, you wrote:
>OK, one guy says "might be Gottlieb" and another talks about "pulse
>stretchers".
>
>How about this, just before Gottlieb went out of business they claimed
>to be using piezo switches. The ball hits it, it puts out a pulse. I
>never saw how they were doing it, but a piezo pulse would need
>stretching, wouldn't it?
>
>Hey John, you might know about late vintage Gottliebs, how did they
>handle the piezo switches?
>
>
>
>mccullar wrote:
> >
> > Don't know exactly what the board is used for, but I can say that 74221
> > chips are often used as "pulse-stretchers." That is, it takes an input
> > pulse and the output pulse is of a width that is dictated by a
> > resistor-capacitor combination. Each 74221 is made up of two separate
> > pulse-stretchers, so this board effectively has six channels. Perhaps in
> > the past a different game board was used inside the cabinet and input
> > signals were "stretched" to give the computer more time to time to
> recognize
> > joystick or coin switch commands. Wild guess...
> >
> > Matt J. McCullar
> > Arlington, TX
> >
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Received on Sat Dec 15 12:44:46 2001