Re: -28V on a Space Duel board

Thanks Jess and Al. I had the schems but I didn't know that a 555 and caps could
produce twice the voltage. I'm great at wiring but have a long way to go in the
electronics dept. :) It seems I don't have anything less than 12mhz on the clock
circuit so I guess I've got bigger probs anyway. :(

Dan

On Sun, 23 May 1999 21:37:49 -0600, you wrote:

>> Anyone out there familiar with the Space Duel board? There is a test terminal
>> for -28V, which is only at -15 or so on mine. I tried following it back and
>> cannot determine the origin of the -28V. Could someone explain it to me?
>>
>> Thanks,
>> Dan
>
>The -28V is actually made by the -15V supply. There is a 555 timer that
>runs at a continous frequency and goes into a capacitor voltage doubler.
>If the 555 is running, then your caps are probably dried out
>(electrolytic). I think that Al has all the schems up at
>www.spies.com/arcade
Received on Sun May 23 23:17:26 1999