Viewing Issue Advanced Details
ID Category [?] Severity [?] Reproducibility Date Submitted Last Update
07976 DIP/Input Minor Always May 10, 2021, 13:29 May 13, 2021, 13:26
Tester dink View Status Public Platform MAME (Official Binary)
Assigned To Resolution Open OS
Status [?] Acknowledged Driver pacman.cpp
Version 0.231 Fixed in Version Build
Fixed in Git Commit Github Pull Request #
Summary 07976: mspactwin: P1 springs to life in a P2-only game
Description P1 springs to life in a P2-only game.
Steps To Reproduce Reproduce:
1: start a p2 game
2: eat power pellet
3: as the pellet sound plays, move p1's controlls around (U,D,L,R)
P1 will spring to life, most of the time trapped up top or bottom of the screen, but sometimes she breaks out onto the maze.

This could be a game-bug (aka BTANB), but I have my doubts as too often someone would come up and start fiddling with the inactive player's controlls, at least, from what I remember back in the day... I'm sure they tested for that.
I think it's probable that there is some sort of mask(multiplexor?) that selectively enables the inputs. I didn't investigate that though.
Additional Information Curiously, the green "18" at the bottom left of the titlescreen is a "0" on the pcb video from Roberto Fresca, maybe a clue?
video can be found @ "MS PACMAN TWIN" link, bottom of page.
Github Commit
Regression Version
Affected Sets / Systems mspactwin
Attached Files
related to 07962Acknowledged  mspactwin: 2 player dots finished but game will not advance to level 3 
User avatar
Senior Tester
May 10, 2021, 23:55
edited on: May 10, 2021, 23:55
you're better qualified than most to study this dink, but my gut feeling is the flaws in this thing are just going to be bugs in the game. Once you start to hack something to the extent this was hacked up you're going to end up with unexpected problems, especially if there's no testing beyond a small release to a very specific market.

although yes, I do wonder what that 18 vs 0 thing is.
User avatar
May 12, 2021, 07:19
edited on: May 12, 2021, 07:26
18 is hard-coded in the rom at 3853. The code that draws the screen reads this and writes it to screen memory 407F for '1', and 405F for '8'.

The avi clip does indeed show 0 so I'd say this set has a few unknown mysteries yet to be solved.
User avatar
May 13, 2021, 13:26
edited on: May 13, 2021, 13:28
Haze thanks, the purpose of writing this was to document so it doesn't get forgotten (my memory is full of holes lately).
One thing I'm curious about is that little circuit added to the pcb, do you recognize which pins it is connecting to on the edge connector?
My thoughts are, without being able to find a pinout for that connector:
a replacement amp -or-
some sort of input manipulator/latch/timer/???/?
(the pcb pics are on the site listed in the additional info: field above)

best regards,
- dink