Re: Testing Galaga...

John,

I assume it would be okay to incorporate this in my Galaga repair page (that
I need to work on some more....)

http://users.erols.com/mowerman/Galaga/Galagafix.htm

This is not a publically advertized page yet, Techtool list members may make
use of it but please don't publically advertize it yet.

As always, direct any comments to

Kev
mowerman@erols.com

Thanks!

> As many of you might know, Galaga presents some interesting headaches due
> to it being a multi-processor board, and sometimes the 74LS367's that
> interface the three processors to the system address bus can have
problems.
> How to find the problem is where this trick lies. Get yourself a Z80 NOP
> and plug it into the Z80 socket for each of the three Z80's - one at a
> time. Now you can check the buffered address bus with ease at the pull-up
> resistors,finding any bad connections or bad 376's very quickly.
>
> I made up a Z80 NOP a few years ago, this has a Z80 CPU with the data
legs,
> reset, NMI, Halt legs all bent up and over the top of the CPU, then you
tie
> the DATA lines to NOP (00 I think), and the CPU controls to high with a
> pull-up resistor. Make a simple Reset circuit with a diode, capacitor and
> resistor so the Z80-NOP will ignore the board and away you go! This works
> for most processors by the way...some more info on NOPs is on
> http://www.spies.com/arcade I think where Al archived some of my notes...
>
> John :-#)#
>
> John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
> Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
> http://www.flippers.com
> "Old pinballers never die, they just flip out."
>
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>
Received on Thu Sep 21 08:16:40 2000