Asteroids/Asteroids Deluxe symptoms and resolutions

As I've just fixed a couple of faults, one on an Asteroids board, the other
on an Asteroids Deluxe, I thought it might be beneficial to a few people
here if I put up the symptoms and the resolutions (neither of which are
covered by the very good Asteroids Troublshooting Encyclopedia at:
http://www.ionpool.net/arcade/asteroidtech/asteroidsrepair.html - that's
not a criticism of this great resource, after all, nothing can ever cover
EVERY fault and EVERY possible resolution!).

Firstly, the Asteroids Deluxe problem - on powering on the board, there was
no display (monitor, etc were fine). At first I thought it was a problem in
the main Z Output circuitry (the portion detailed in the schematics).
However, after the machine had been switched on for a few minutes the
display started to appear in a very 'bitty' manner, with the 'pixels' (I
know, they're NOT pixels, it's the best description I can think of!)
flickering, some being drawn, some not, etc. As things warmed up the
display became more stable and more solid. The application of some freezer
spray soon located the failing IC, a 74LS157N at location F/H10. Replaced
this and all is well. :-)

Secondly, the Asteroids problem - the board had been working fine, but all
of a sudden the saucer firing sound turned into a buzz - on looking through
the schematics I located those related to the saucer fire sound. Tested out
some components and, as the 74LS259N at location M11 was socketed (as was
another, the one for the thrust sound) I swapped them, and the saucer sound
was fine with the thrust sound corrupted. In other words the 74LS259N at
M11 was at fault, so I replaced that and all was fixed. :-)

Of course, both of the above resolutions might not fix similar faults -
after all, there's more than one component on a board and more than one
responsible for various parts of a circuit. :)

I hope this information is of use to someone and that no-one thinks I'm
'clogging up' this excellent board. It might be useful if others could post
their symptoms and resolutions to various faults too - any vector game will
do, but maybe some people here wouldn't like that as the board would just
become a 'dumping ground' for information of resolving faults (albeit very
useful information!).

Or maybe we need somewhere else to 'dump' all this knowledge? I'm sure many
of us have useful info related to faults we've fixed, so why not share it
with everyone? Of course, looking back through the Vectorlist archives will
turn up all kinds of goodies, but out of necessity it's usually buried
amongst other information so can be tricky to find.

Any thoughts anyone?

Phil

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Received on Fri Feb 8 09:57:07 2002