<html>
Hi Kev!<br>
<br>
Sure, please feel free to add it. I sent a copy to Star Tech as well...<br>
<br>
John :-#)#<br>
<br>
At 06:01 AM 9/21/00, Kev wrote:<br>
<blockquote type=cite cite>John,<br>
<br>
I assume it would be okay to incorporate this in my Galaga repair page (that<br>
I need to work on some more....)<br>
<br>
<a href="http://users.erols.com/mowerman/Galaga/Galagafix.htm" eudora="autourl">http://users.erols.com/mowerman/Galaga/Galagafix.htm</a><br>
<br>
This is not a publically advertized page yet, Techtool list members may make<br>
use of it but please don't publically advertize it yet.<br>
<br>
As always, direct any comments to<br>
<br>
Kev<br>
mowerman@erols.com<br>
<br>
Thanks!<br>
<br>
<br>
> As many of you might know, Galaga presents some interesting headaches due<br>
> to it being a multi-processor board, and sometimes the 74LS367's that<br>
> interface the three processors to the system address bus can have<br>
problems.<br>
> How to find the problem is where this trick lies. Get yourself a Z80 NOP<br>
> and plug it into the Z80 socket for each of the three Z80's - one at a<br>
> time. Now you can check the buffered address bus with ease at the pull-up<br>
> resistors,finding any bad connections or bad 376's very quickly.<br>
><br>
> I made up a Z80 NOP a few years ago, this has a Z80 CPU with the data<br>
legs,<br>
> reset, NMI, Halt legs all bent up and over the top of the CPU, then you<br>
tie<br>
> the DATA lines to NOP (00 I think), and the CPU controls to high with a<br>
> pull-up resistor. Make a simple Reset circuit with a diode, capacitor and<br>
> resistor so the Z80-NOP will ignore the board and away you go! This works<br>
> for most processors by the way...some more info on NOPs is on<br>
> http://www.spies.com/arcade I think where Al archived some of my notes...<br>
><br>
> John :-#)#<br>
><br>
> John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9<br>
> Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)<br>
> http://www.flippers.com<br>
> "Old pinballers never die, they just flip out."<br>
><br>
> To UNSUBSCRIBE from techtoolslist, send a message with "UNSUBSCRIBE" in<br>
the<br>
> message body to: techtoolslist-request@flippers.com. Please direct other<br>
> questions, comments, or problems to jrr@flippers.com.<br>
><br>
></blockquote></html>
Received on Thu Sep 21 08:22:21 2000
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