I'm back in this club. I had previously traded the game away and just traded Space Shuttle to get it back.

I just really like this game!

I saw someone else post that they'd like to retheme it. I also have some tentative plans to do that. I've got a lot of other projects lined up, so I'll just enjoy playing it with the current theme for now.

I'm glad to have this game back. I'm really enjoying it again.

With my tentative plans to re-theme it, it occurred to me that the game displays the words "Special Force" at the start of a game. I am happy to discover that most of the text is stored on one of the cpu roms as straight text. In a hex editor I found the title text and edited it. After loosely accomodating for checksums, I got the modified rom to boot in pinmame with an edited title being displayed. I'm hopeful it can boot in the actual game.

The other thing to overcome or assimilate into the new theme is music/sounds. In my quick research, I haven't had any luck so far figuring out how the sounds are stored.

No clue at this point. It'll probably be a while before I try to do anything.

OK, so while I'm not ready to actually do any re-theming, I have been giving it some more thought.

I did a quick experiment. I changed "SPECIAL FORCE" to "___DINO WARS_" and "SOLDIER" to "WARRIOR". I burned the rom and got the actual game to boot with the changes! So that opens up a few possibilities on a re-theme.

For the title, I can't get it to where it blanks out the letters, so I'm using underscores instead and they display as dashes. So the title comes up one letter at a time with the gun shot sound, displaying: - - - D I N O W A R S -

Now at the beginning of each ball it says "WARRIOR 1" instead of SOLDIER.

After making those changes, to accommodate for the checksum I either added new values in the blank space at the bottom of the rom or I edited incidental text, such as the text displayed in the various audits, to decrease values to where the checksum-32 ends up being the same. I'm not that well-versed on checksums, but it's probably possible to change what the game expects to find, but I don't know how to do that.

At any rate, there is various text that's displayed throughout the game stored on the U2 and U3 roms. Both can be edited the same way. The restriction is that the new text needs to be less than or equal to the old text. So it's not going to be possible to lengthen a word, at least not with this easy editing method.

The goal, then, would be to come up with a theme that utilizes the existing text or figure out a clever way of changing the text. "ROCKET" appears quite a bit. Others are "HOSTAGE", "ESCAPE", and "BOMB".

The other challenge with a re-theme is re-purposing the existing mechanics. You've got buttons to fire rockets and lights/sounds to go along with it. You've got bombs to collect, arm and drop by helicopter. The game is very well integrated into a military theme, so re-theming with a military/battle theme would be easiest.

"ROCKET" could become "LASERS" or "SPEARS" or "CANNON"...

I'm not sure on "BOMB"...

Sounds are kind of modern warfare sounds due to gunshots, explosions, etc. That kind of restricts the theme to a more modern type of war theme as opposed to medieval, etc. You've also got the cricket sounds, so the jungle/woods theme probably has to stay if those are staying...

At any rate, if I keep the theme pretty similar, it could be fun to have it re-themed to dinosaurs in a modern war. Some of the stock sounds that are supposed to be explosions or rocket propulsion or something already sound like dinosaurs to me and I like dinosaurs, so may go that route.

That's certainly a viable theme! Just change backglass and playfield art and you're basically good to go.
"SPECIAL FORCE"
"---PRED ATOR-"

Other than the idea of keeping the game collectible, I don't see much reason not to change the theme. Special Force is a very under-rated and under-valued game. I think it would be hard to sell even an HUO premium example of the game for very much. Because of that, I don't see much point in trying to retain the already low value in my own game. If I see it as a keeper anyway, why not change the theme to something more appealing to me?

Don't you have a couple playfields? If you weren't modifying the cabinet, just retheme one playfield and make a new translite and then everything's swappable and reversible.

Ok, so a little more experimentation has lead me to the conclusion that the recorded sound effects are stored on the sound roms as unsigned 8-bit data, and that the first pair of roms have two channels of the same sounds and the 2nd pair has two channels of the same sounds.

The sound rom can be imported into Audacity and played back.

This includes all gunshots, explosions and crickets. That means if you replace the sound with another that is less than or equal in length, it should be possible to change them.

My assumption is that the music is not a recorded sound, but likely the result of some kind of on-board synthesizer. I'm not sure where that data is stored, but the beginning of the first pair of rom files is not recorded sound data.

And just one more nugget of discovery: I noticed a lot of patterns in the data at the beginning of the first two sound roms and my guess is that this is somehow tied to the music. I edited some values and got some sections of the music to sound way off!

The checksums on these sound files are going to be more difficult to get around using the method of trying to balance everything out by subtracting somewhere if adding somewhere else. There isn't much blank space on these roms. So sound/music editing is likely going to require figuring out how to change what the game expects from a checksum on the sound roms. I don't know how to do that at this time.

Is Strange Science on a different sound board? I see it only has one sound rom when compared to the 4 in Special Force. I'm not familiar with the game, so don't recognize the sounds when I play them back, but these are the settings I use to import the RAW data from Special Force into Audacity.
Audacity Import - Special Force Sound Rom.png

I think when you're manually slowing it down, you're effectively doing the same thing as importing it at a lower sample rate. Maybe import it at a super low number and see if you can find everything.

Special Force seems to be different. Every sound seems to be at the same speed and all are present and accounted for as far as I can tell. Hopefully that will make modifications easier in SF.

I messed around some with the debug feature in Pinmame, but can't figure out how to effectively use it. It seems to stay in one of the sound roms in spite of other stuff happening in the game and I don't know how to get it to move to a different rom. I was hoping to figure out how to bypass or change the checksums for the initial sound board boot sequence, but am not having any luck so far.

I almost never get the ball up that ramp.

It might have to do with the pitch of the playfield. I would guess a more extreme pitch would make that ramp more difficult.

Towards the top? It doesn't go anywhere.

You can dye the white ones yourself with Rit Dye. I did it and it worked great. I don't think you'll find green ones.

Was it me? I had posted about looking into the roms and editing text. I didn't get far with the sound roms.

I seem to recall there being a rundown of these options in the manual describing what they do.

I don't know exactly off hand what they are, but I think chimes ends up with electronic sounds like bleeps and bloops and nothing else, sounds is probably enabling both sound effects and background, and background would just be the background music and no sound effects.

Edit: Actually there are 4 options for sounds (0-3) and they're described in the manual which can be downloaded from IPDB.

What I'm referring to is on page 1-3, but it's not very descriptive. In fact, do the menu items in-game say the same thing as the manual?

It looks like the 4 options are chimes w/o background, sounds w/o background, chimes w/ background, and sounds w/ background, so no options to turn off bg sound.

I do believe I'm correct about chimes being electronic sounds instead of the sound effects, but I honestly have never tried. There isn't a physical chime unit in the game.

All balls have to be present in the trough for a game to start. If they are present, then make sure the trough switches are working properly.