Asteroids Deluxe Resetting Problem

Ok, here is a fun one.

My AD was working just great two nights ago. Power it up tonight, resets. I
go into test mode, still resets. Funny thing it is I can see the test
pattern on the screen and all the goodies that go along with it (the ships,
the gradient, the numbers etc).. so as it resets, the screen flashes the
test screen over and over again (it resets slow enough that it has time to
display all that stuff).

When I switch to game more, I can barely see the title screen come up
(credits, game over, copyright message etc) again.. resets ... but once in
awhile I see the message in the lower centre of the screen "BANK ERROR" and
then a string of what looks like 88:88 88:88 or maybe it's BB:BB or
something..

I looked up "BANK ERROR" and it says that it indicates something wrong with
the invert circuit, but because this thing is resetting constantly I think
it is a false positive. I tie the watchdog to ground and the game stops
reset, BUT, the screen still flashes off and on like it's resetting... I
know it's not resetting though, because I can add credits and play the game
- not blind mind you, I can see the ship, asteroids, other things.. but a
lot of the time vectors are screwed up here and there..

Now I have replaced the transistors in the invert circuit, practically the
entire Vector State machine circuit (except for N4) and a series of other
chips around (mostly ones that had direct !reset connections. Nothing.
Still does the same thing. I am really puzzled. I would like to not have
to replace every damn chip, but it's frustrating. Everytime I follow the
schematics and I think I am making sense in my next decision, it proves
useless.

Anyone have any ideas on what to check, or how to check, or even encountered
this one before?

Thanks
Andy

Andrew Evrovski
HPC Development Director
Cyberplex
t: 902.429.4721 ext.109
f: 902.423.0899
www.cyberplex.com
---------------------------------------------------------------------------
** To UNSUBSCRIBE from vectorlist, send a message with "UNSUBSCRIBE" in the
** message body to vectorlist-request@synthcom.com. Please direct other
** questions, comments, or problems to neil@synthcom.com.
Received on Thu Nov 29 23:10:21 2001