The board was not booting and kept resetting meaning watchdog was active :
The video board was marked by owner as good hence I focused on the CPU board./HALT line of 68000 main CPU was stuck low meaning it was stopped :
Board was heavily populated with Fujitsu TTLs and we are all aware about poor reliability of these parts.They usually fail showing floating outptus and this is what I experienced while checking them, my probe was not detecting any logic level on some (all 74LS244, a bad lot perhaps?)
A good rule when you encounter Fujitsu TTLs would be to replace them all because they sooner or later fail.In this case I started to pull out the suspicious ones, three of them were really bad :
After replaced them the board finally got past the POST and entered in game but while testing I noticed that a music track and some sound FXs were missing :
Checking with an audio probe revealed music and sound FXs were fully generated but then they didn't reach the inputs of the amplifer.I scratched my head to figure out this and after some time I remembered that this board has stereo sound and, like in other Konami games, you must close a jumper (the 'CN2' MONO or the 'CN3' STEREO one) in order to hear both channels :
This is what I did giving full glory back to this great game!
P.S.
You can read more about Konami stereo sound in this post by my mate Yves:
Konami stereo sound
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