Well... I am replying to my own message in the hopes it may help someone
else. I finally figured it out last night. I looked through the schematics
and found out that there is one part of the circuit that behaves differently
in game mode vs test mode. When you are in test mode, the NMI part of the
circuit is disabled. When in game made, it of course is active. Well,
there are essentially 2 chips that are directly involved here. The first
one is C5 (LS161 - counter) and B5(7404 hex inverter) - this is attached to
the output of the counter and directly to the NMI pin on the 6502A
processor.
So.... I had already replaced the C5, so I replaced the 7404 (B5) and
presto. Game came up!
Thanks to all who may have listened and were planning a reponse (or
responded).
Cheers
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 Wed Oct 3 05:38:23 2001
This archive was generated by hypermail 2.1.8 : Fri Aug 01 2003 - 00:33:43 EDT