Cool, I'm marking as a favorite. Sadly, I have nothing to add.

I'm all in favor of fixing bugs in the code; I'm not at all a fan of people changing things "they think is needed."
More power to you.

There's a bug in the code of the left Magna Save button in Jungle Lord that messes up the lamps when you press the button during the light show when Stampede Mode is started. Jess Askey provided the fix, which is included in all the different home ROM versions floating around.

My other two games -- Alien Poker and Pin Bot -- also have bugs, but I have not upgraded these to the most up-to-date codes. Just yesterday I was finally ready to upgrade Pin Bot only to break both sockets on removing the original chips. The sockets have zero springiness left for maintaining contact or even holding the chips in place -- quite a funnily annoying failure mode, I ended up thinking. And now I have some board work on my to-do list, before I can even play again.

Ours is a great hobby

Hah! This accounts for why I always try to play "stripes" on EBD in mulitplayer games. I thought it was just because I liked hearing the game say "You've got Stripes" was cool, but now I realize that I was hoping to capitalize on some sweet unearned bonus-points!

Bally Goldball had a very dull attract mode in the original version.
After the Field kit upgrade nothing better happened.
It only made getting the Golden Ball a skill rather than a random feature.
Together with Oliver Okaegi I worked on a new attract mode lights sequence.
While were at it I decided to change some sounds too.
Some were not used, others seem inappropriate.
There some other chages too.

Here is a copy of the readme.txt file:

add 7-digit displays for player 1 - 4 (optional), add version nummber, recalculate checksum.
installation notes (optional):
Replace the four player 6-digit displays with 7-digit displays.
Add an additional wire fom A4 (mpu) J1 Pin 7 to every player display pin 12 (don't connect the credit display !)
installation note:
Burn the U6 amd U2 files on 2732 eproms.
After power on you will see the version number in the one player display.
You can leave the 6 digit displays in place no dip switch is needed, because goldball internally works with 7 digit scoring.
New with version 10:
Improved attract modus (based on ideas from inkochnito).
Enable freegame when dip 25 and dip 26 = on (credit not lower then 01).
This version is based on the Bally Gold Ball service kit, this means when
if dip14 = 0 and dip15 = 0 and dip16 = 0
the "Goldball" is reached when you complete the Goldball letters.
Also dip24 = 1 means:
Top Rollover Button, Goldball special when flashing, comes on at the start of "Goldball" play, and every subsequent ball-in-play if not collected.
Also dip24 = 0 means:
Top Rollover Button, Goldball special when flashing, comes on at the sort of "Goldball" play.
For the following events the sound had changed:
special award, 10 point rebound, Goldball complete, 30 points rebound, PLAY lanes miss letter center (left and right target), spot goldball letter, left return lane, top right star, right star, extra ball awarded, tilt, PLAY already lit, right and inner left outlane, target 1, 2, 3 already lit, target 1, 2, 3, 1-2-3 complete.
Play lanes (50k, extra ball, special) always reset if dip switch 7 is off.
New version 12:
Correct GI problem, Golball complete only played once.

Seymour-shadow on RGP tackled a number of bally/stern game bugs, from what I recall.

I really appreciate the work on improving game rules in older games, but please let this thread be for actually documenting bugs in original software, to help hobbyist developers finding out what needs to be fixed.
å

Has anyone made Bally/Stern roms with freeplay?

Great idea to link all "new roms" in one thread if that's the idea here, it would be great if there's a "master list" in the first post that you update as they come out each quarter or so.

Otherwise, we need a new thread for that.

-mof

I wish there was a site that hosted all the patches, had lists of games, etc..

Could even have an integrated JS patcher and doubler

Never seen the left side kickout issue on mine and I can's simulate it either. Could the top long flipper not activating in game over be incase one of those top pocket switches is stuck so to prevent the motor spinning 24/7??
Maybe the ideal way is to run the long flipper motor for 15 seconds max on powerup if one of those pocket switches is sensed as closed.

Not quite, in freeplay my method allows zero credits, but when they're zero the credit display goes blank. "00" credits is never displayed. Credits are always reset to zero at the start of a game, and anytime you accumulate credits they are displayed. It adds incentive to see how many credits you can win in one game. I also want to add the maximum credits achieved to show when "high score to date" is displayed like a highest credits to date. There's just too.. many.. projects....

These are not show stoppers:

Bally Eight Ball and Black Jack, not that there's any way it can happen but if the first score on a ball is the spinner the game will tilt.

Bally Freedom, Night Rider, Evel Knievel, Eight Ball have a tilt exploit. Lift the machine so the ball in play tilts. While holding the machine up, allow the ball to go to the outhole. Provided you're still holding the machine up, the next ball will be served with tilt off allowing you to slowly maneuver the ball and score at will. Factory Eight Ball fix is on IPDB.

Bally Playboy, trivial really - in attract mode the displays cycling between player scores, blanking and showing to highest scores to date sometimes gets out of sync (noticeable in the first minute of powerup).

Would be glad to. Will reply to your email later today.

How cool would it be to see the Bally’s have the same “If you tilt with no points, you get it back” rule that the early Sterns have? I’m sure it would be abused SOMEHOW in the tournament scene but would avoid the carryover tilts so there’s something good about it

Early Bally SS suffered from a bounce bug where drop targets would keep scoring via switch bounce when knocked down. This problem was fixed post 8-ball by modifying the software to ignore any subsequent target down switch closures until the target bank is reset. Would be nice to add this fix to the early games.

Yes, they've been fixed. And recently when I was looking at Sterns Stingray/Pinball it also has the switch bounce issue with the drop targets (now fixed) so you're probably right about the other MPU-100 games having the problem.

Not a game play bug or a bug that happens in normal circumstance, but I have noticed in bally games you push the NMI button immediately after pushing the test button while the last audit is selected you can crash the software. Solenoids/displays/lamps may erroneously enable, and it will usually corrupt the RAM. I am not sure if this happens in all games but there is at least one Bally OS rom this happens in.

I get this bug trying to clear audits quickly and I am not paying attention to the fact the last audit is display and im rapidly pushing test and NMI button to cycle and clear every audit.

Similar not critical bug in MPU200 games if you push the NMI button before the test button the software crashes. Nothing bad happens tho in this case. Game just goes dead and you have to reboot.

I seem to remember Firepower will round off the 100s or 10s in your HSTD in some cases. It might be related to the divide by ten ROM tho, I can't remember exactly.

Alien Poker - maybe other System 6 games also: If ball bounces while landing on a hole kicker, triggers but misses the kickout arm and then settles at hole, the game will not recognize ball in hole, requiring power cycle to continue. Back then, this happened so often that I wired an extra EOS switch to one flipper, breaking the circuit of top hole switch. Then if the ball got stuck in top hole, players instinctively flipped, getting the game to notice the ball in hole and kicking it out. All 3 eject holes behaved like that, it was probably because of playfield layout that the top hole was the only one that really suffered from the problem.

Wasn't there a 'feature' that changed the 'last score' display by 10 when you got the HSTD, so the numbers changed on the display when it cycled between last game and HSTD?

some more bugs/quirks in Bally games that is probably not worth the time to fix but will document it.

Six million dollar man fails to boot to attract mode if DIP-31 is turned on. I know this is some kind of feature for test operators to see an audit value quickly, but it confuses people because the game looks like its dead after boot with random info on the displays.

In games like Future Spa and Kiss the quick reaction solenoids fire during switch test. I think it effects all the games using the same OS ROM as kiss/future spa. This behavior doesn't happen in earlier or later games. Does not effect Lost World, but starts in the next game after. The feature lamps also blink during displays test in these games. With incandescent the blink is so short the filament hardly glows but it is a apparent with LEDs.

There is a game where random different feature lamps light up as you scroll through audits, but I can't remember which game right now.

I found three bugs in the Pinbot L5 code. I have fixes for all of them and would *like* to release those but am not sure how. In the mean time, here's documentation:

Bug#1 Energy Value Limit. The Energy Value is supposed to be limited to 500K. Instead, it starts looping like this : 498-500-502-504-506-508-500-502-... The culprit is a subroutine starting at address $627A. This bug is largely cosmetic.

Bug#2 Solar Value Limit. There is a similar bug in the Solar Value limit, which is supposed to be limited to 5M. The buggy routine starts at $77CB.

Bug#3 Visor Open code. This is an interesting bug; I do not think that it affects game play on machines with fully functional visor mechs. It might well affect games with visor problems, though. The problem occurs when the visor is already open and the software, for one reason or another, decides that it wants to open the visor. In that case, what the code should do (as it does in the visor-closing routines) is simply ignore the visor open command. What it does, instead, is cycle the visor (close, then open). The underlying problem is that a BGT instruction (at $B769) is used to test a variable that takes on only the values 0 and -1 ($FF). Neither of those two values causes the BGT to branch. The bug can be fixed by replacing the BGT either with a BPL or a BEQ and updating the checksum byte at address $BFFF.

Appears that Stern Ali has a sound bug similar to Meteor. The game/ball start noise, a bell ring noise, can go wrong in certain situations. I can't figure out what exact steps causes it but it seems like if you start test mode during game play at the wrong time it can happen.

If I start a game. Score 500 point switch. Put it into test mode. Reset the game and there is about 50/50 chance the bell noise will be wrong. Can fix it my clearing the RAM or seems to fix itself after a reboots. If you have random junk in RAM from a different game the seems like the issue may appear as well.

John's Jukes mentioned Superman has a scoring bug and was looking for the updated ROM. Anyone have the image files? Check out the notes in the scan below.

Untitled (resized).png

It would be a great upgrade on early SS Bally to separate the Extra ball settings from the special settings like Stern did.
As it is now on most of these titles, setting special reward to points makes the extra ball set to reward points as well.
Early SS Stern got it right with their settings to separate the extra ball and specials. So you could earn an extra ball while achieving points for every earned special instead of a free game.
Would be great to get the credit knock as well as points if possible. (Perhaps program it to get the points and the knock and the free game for every special achieved?)

Is there a particular game you have in mind?...

I don't know if it is a bug or not, but there is something with F-14 Tomcat.

When you set the game to award no extra balls, the Flight Insurance (ball saver) still gets activated.
You get the sound, but not the ball.
Just like the extra ball you don't get when awarded.
It would be nice to get Flight Insurance as ball saver, but not the extra ball (tournament setting).
I think the game sees both the Extra Ball and the Flight Insurance as Extra Ball and doesn't award them both.

I hope this makes sence to you....

While making the “PEMBOT (no relation)” home ROM, I found and fixed the following bugs in the L-5 release of the Pinbot code. Earlier versions have additional bugs that I did not look into.

• When two switches are hit simultaneously during the chest skillshot (i.e. when one lit and one unlit targets are hit), the skillshot is only awarded when the left target is lit but not when the right target is lit, i.e. the skillshot is not always awarded when a lit target is hit.

• During multiball when one of the balls ends up in the shooter lane double scoring is disabled and should stay disabled until the ball is served again. However, double scoring is re-enabled erroneously whenever the other ball that’s still in play hits any switch.

• Timed shots are paused when a new ball is served. While timed shots are paused they continue making sound but do not blink, which makes it impossible to see which shots are active.

• Timed shots are paused on entering the ramp and re-started when the upper PF is exited via the right inlane or the shooter lane. However, the timers are not restarted on aborted ramp shots or when the ball exits the upper playfield over the side and the ramp thunderstorm F/X times out. As a result, you can trap such a ball and have an infinite amount of time to make the timed shots.

• Both the Solar and Energy value show weird behavior around their max value. The energy value, which should max out at 500K, shows the following sequence 498K, 500k, 502K, 504K, 506K, 508K, 500K, 502K, …

• When a game is restarted with the start button during balls 2 or 3 the current game is aborted. When open, the visor closes immediately and any locked ball is available as a “stolen lock” for the newly started game.

• During multiplayer games, after a ball has drained but before the bonus count begins, the lamp status of the next player flashes briefly on the playfield while the game checks to see whether the visor should be opened/closed for the next player.

• When the single eject is set on a timer, and the shot is enabled by making the right inlane, the corresponding lamp (25K, 50K, 75K, EB) starts blinking. When the shot is made, the corresponding lamp is lit. When the shot is left to time out instead, the corresponding lamp is lit as well. As a result, you cannot tell from the lit lamps whether the next award to be enabled with the inlane is the last one that is lit or the first one that is unlit.

• The timeout for entering initials after a high score is too short and you never get to hear the very nice ending of the high-score melody.

Special Force, if that counts as early SS.

There is a drop target in front of the 180 ramp that awards collect weapon (advance weapon bonus). When you knock the drop target down with the ball, the collect weapon light blinks. When you knock down the target with a rocket, right extra cab button pushed, the collect weapon light does not blink yet that shot awards collect weapon either way.

Pretty sure that the collect weapon light should be blinking whenever the drop target in front of the 180 ramp is down.

Alien Poker and Scorpion (and maybe other early Williams solid states) will lose game progress on a tilt.

Years and years ago I installed the Oliver EBD rom with the odds/evens bonus bug fix and the little added extra feature of shooting the DELUXE letters in sequence, it was cool. That board went south and I put in an Altek CPU board. So fixing bugs/changing versions with an aftermarket board like that with multiple games coded into it is moot, right? Wish they made them with USB ports and the ability to do that somehow.

Ah you are correct, I just tested it, bonus bug is fixed. I guess I figured they would have only used original Bally code so I never tried it. The little extra DELUXE sequence feature is not there though so maybe it's the code on IPDB that says it ONLY fixes the bonus bug.

Never heard of that one, I'll have to try it on mine. It actually kinda makes sense as a reward - if you manage to get the replay level down below, you *deserve* two replays!

I verified it with sw. 27 on or off (changes the rules of how the sequence starts), either way the extra DELUXE sequence feature in his final custom version is not in there.