> Some of the micros can have bits set to 1's by hitting
> them with a voltage spike. When we were teenagers I saw
> a piezo spark igniter (reliably) clock up games on a
> Galaga arcade machine, by zapping the main coin entry
> plate it spiked the micro and instantly jumped the
> "coins" variable from 0 to 99. I assume the spike set
> the variable to all 1's (0xFF) and safety code trimmed
> it to 99 for the 2 digit display. Sometimes the video
> ram to the Z80 micro got hit and most of the screen
> would go white. I was employed part time fixing these
> machines and saw the results of deliberate spike attacks
> regularly. :o)
> -Roman

I remember this well.. There was an entire line of games
built with a similar motherboard. Simply rubbing your
feet on the carpet and touching the coin door was enough
to get you a free game. It also registered on the coin meter,
so the operator was left wondering where the quarters went.

Many fixes were tried. Sattellite boards were built to absorb
spikes at the main edge connector on the motherboard. They
were useless.
The "real fix" came by mixing a 50/50 solution of Downy fabric
softener and water. Spray the carpets once a month. No more
static, problem solved at the source.

I still use this trick to reduce static in the home and car. The only
change is that now it's "Ultra Downy", so the mix is more water
and less downy.

Lyle
>
> --
> http://www.piclist.com hint: The list server can filter out subtopics
> (like ads or off topics) for you. See http://www.piclist.com/#topics
>
>
>

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics