TechTools Archives: Re: [techtoolslist] Pong

From: John Robertson <jrr_at_flippers.com>
Date: Mon Sep 29 2003 - 22:15:20 EDT

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Maybe not a crack wiz (not sure if I like that image ;-) but have fixed a
few in my time... 
At 08:00 PM 29/09/2003 -0400, James Bright wrote: 
<blockquote type=cite class=cite cite>  
 
If I remember correctly, John is a crack wiz
with Ping boards (Am I right? Memory is vague on this one). Figure Id try
something a little different in the mean time and look at a couple of
non-CPU based boards
J
Ive got the schems (no manual), so wanted to ask a few general questions.
Ive included the pinout that I have below for reference. I believe it to
be the correct one. 
 
  
 
1) Im guessing that I can just drive the board
off of +5 and gnd and ignore the xformer. Looking at the schems (they are
*very* fuzzy in the version Im looking at), that looks to be it.
Guess Im half thinking aloud here& 
 
</blockquote> 
Yes, they generally all ran off ordinary +5VDC - took about 3amps
AIR. 
 
<blockquote type=cite class=cite cite>2)
Monitor. I see a composite sync line on the schems, but note explicitly
documented in the wire diagram. But Im guessing that you can just pick a
color (or tie all three together) and just run it into a normal monitor.
 
 
</blockquote> 
These games were usually B&W composite. Look for the VIDEO line,
ground being the other. Unshielded twisted pair ran up to the
Motorola/Wells Gardner/Ball Brothers monitor. 
<blockquote type=cite class=cite cite>  
 
3) Antenna? FCC regulation or something?
Interesting.   
 
</blockquote> 
ANT was for forcing a reset on the board if someone tried to zap it for a
free play...it was a piece of wire about 18" long and if it picked
up a spike would clear the TTL registers. 
 
<blockquote type=cite class=cite cite>  
 
4) Any other gotchas? I was going to start
playing around with it tonight during MNF. I do have a Pong on hand right
now, so I can also peek inside. Just much easier to run the thing on my
bench. 
 
</blockquote> 
You can follow the image through the board if you make a Video Probe -
essentially a wire probe with a resistor (something like 10k) in series
and tied to the video input of the monitor. You can then visually trace
the ball, paddles, and clock circuits - The Book by
ATARI is great for this information - was up on Spies but I can email you
a PDF of it. 
Paddles were usually 10K pots wired across the +5/ground so the wiper
would go from around 4V to around 1V - this was fed into a 555 that would
change it's output pulse length in accordance. 
John :-#)# 
<blockquote type=cite class=cite cite>  
 
Pinout 
 
  
 
 1 transformer 
 
 2 
 
 3 
 
 4 transformer 
 
 5 
 
 6 transformer 
 
 7 
 
 8 +5 
 
 9 +5 
 
10 Coin NO 
 
11 
 
12 Coin NC 
 
13 
 
14 Paddle 1 
 
15 Ant (wtf???) 
 
16 Sound 
 
17 
 
18 Paddle 2 
 
19 
 
20 Video 
 
21 
 
22 Gnd 
 
  
 
  
 
--James Bright 
<a href="http://www.quarterarcade.com/" eudora="autourl">www.QuarterArcade.com</a> 
Restored Arcade Games for your Home 
 
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Received on Mon Sep 29 19:37:00 2003

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