Re: Asteroids Troubleshooting??? STJ articles??

I found this in one of my inboxes...

On Nov 12, 9:01am, Paul Tonizzo wrote:
> Subject: Re: Need Guide to Tshooting Asteroid boards
> Keith,
>
> I posted this a couple weeks back, it should help.
>
>
> To: vectorlist@mcfeeley.cc.utexas.edu
> cc:
> Subject: Re: Major Havoc help (was: Vectrex on Vector Monitor?)
>
> My contribution to the Vector Fix-it FAQ,,, :')
>
> For Asteroids and Asteroids Deluxe boards with no signs of life:
>
> Unplug the monitor from the harness at it's molex connector to avoid
> damage to it - when the monitor sits in spot killer state too long things
> can fry!
>
> 1. Start out by verifying that the clock is running. (The crystal on
> these boards
> breaks off WAY too easily.) Then check that the CPU and ROM's are good.
> If you found nothing or it's still dead, you've got a watchdog reset
> happening - see if pin 40 of the CPU is toggling (it's supposed to be held
> high).
>
> 2. To figure out who is causing the watchdog resets (the MPU or the VSM
> (Vector
> State Machine)), take the 74LS42 at L5 (L6 on Asteroids) and socket it,
> then
> lift out pin 1 to isolate DMAG0.
> a) If the board stops resetting, the MPU is not the problem and you
> should be
> able to play a game "blind" or switch into test mode and listen for any
> beeps
> indicating RAM/ROM problems. That will at least help you get the MPU side
> running properly and then you can play the game blind.
> b) A board that is still resetting has a problem with the MPU and also
> possibly
> the VSM. Check the ROMS, RAM and especially the 74LS245 (or AM83048)
> at E2 (E3 on Asteroids). Once you fix the reset problem, switching to
> test mode
> should reveal any other missed RAM/ROM issues and verify the MPU is
> running ok. You should now be able to play the game blind.
>
> 3) Place pin 1 of the 74LS42 (DMAG0) back into it's socket. If the
> watchdog is
> resetting, it's time to look at the VSM side of things. If it's not
> resetting, plug
> the monitor back into the harness and look for some video.
>
> For the VSM, check the PROM at C8 (C9 on Asteroids) and surrounding state
> machine signals for HALT, DMAGO, STOP, GO and the like. The rest is pure
> grunt
> work to check the state machine is running properly. Someone else please
> feel free to add details to the VSM debug procedure...
>
> Paul
>
>
>
>
>
> Keith Sink <KeithS@onyx.com> on 11/11/98 06:47:40 PM
>
> Please respond to vectorlist@mcfeeley.cc.utexas.edu
>
> To: vectorlist@mcfeeley.cc.utexas.edu
> cc: (bcc: Paul Tonizzo/SYBASE)
> Subject: Need Guide to Tshooting Asteroid boards
>
>
>
>
> Can anyone give me a guide to diagnosing problems on an Asteroids board? I
> have two. One seems to have a broken trace that I'm going to have to track
> down. The other does some beeps and the counter begins clicking away. No
> game sounds or video.
>
> All I have for diagnostic tools is a digital volt meter.
>
> Any advice and guidance is appreciated.
>
> -Keith
>
>
>
>
>
>
>-- End of excerpt from Paul Tonizzo
Received on Thu Feb 4 15:23:14 1999