Quoted from Robotworkshop:
From the pinmame source it looks like their could be three versions for Monte Carlo. The plain 708, 708/1, and 708/2
Found a list of checksums on flippers.com and that appears to show there are two versions they know about. No checksums listed for the /2 ROMS.
Does anyone have the /2 version? Anyone know what was fixed or changed in each version?
The three versions 708, 708/1 and 708/2 are available, with freeplay modification, at our website: https://www.flipprojets.fr
Two additionnal export versions also exist: 708X for French and 708Y for German.
To my knowledge, I have never seen any mention (except for the James Bond "timed" SYS-80) of the fixes made in the ROMs. In any case, that did not appear in the Gottlieb technical bulletins.
For the Monte Carlo, I made an intensive investigation in the game ROMs:
- The initial version is the 708.
- A first fix was made with the 708/1, which also served as the basis for the 708X and 708Y.
- A second fix has been made with the 708/2, but it seems that it has not been done on the export versions X and Y.
It is therefore advisable to use version 708/2, and useful to know that a small bug still remain in versions 708X and 708Y.
At first glance when we look at the contents of the memories, there are enormous binary differences. But in fact, no.
PROM1 contains a lot of function and table calls to PROM2. After intensive analysis, it appears that finally, all the PROM1 708, 701/1 and 708/2 are structurally identical. The difference is that in the PROM2, modifications were made at the very beginning, which leads to changes of addresses everywhere!
Apart from addressing, the PROM1s have not undergone any modification between versions 708, 708/1 and 708/2.
► From what I understand, patch 708/1 is in the "endgame" section. We can see it easily, because there is the end-of-game sound (0A sound). There is also a fix in a call right after, but I think it's related.
I don't know exactly what the correction is, but it's probably something that was forgotten at the end of the game. For example, a bad count of bonuses, or a reset of the target banks that does not take place, or even a ball remaining stuck in the holes. In any case, it is certainly remarkable at the end of the game.
► Patch 708/2 is much lighter. A table entry has been deleted (but I'm not sure it serves) and a variable reset has been added. Still in the "end of game" section.
Maybe a reset of a forgotten multiplier, or something like that. But which should not be noticed too much, perhaps only in certain rarer conditions (multiballs).
And for those who would like to check, I did a side-by-side comparison of the three versions:
Side by side comparison PROM2 - 708 - 708/1 - 708/2
◈ For the modification of the "million", I will do it only from the 708/2 and the 708X, 708Y. This is unnecessary for the 708 and 708/1 which are older versions.