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.

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.

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.

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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.

Beat the Clock, Eight Ball Champ, and probably the couple other games with same display setup as those games, the restore factory settings in test mode does not work properly. It will leave some audits with bad values that stop the game from taking credits or starting. There is zero error messages and confuses the heck out of people thinking there is a hardware problem.

One of the manuals even says that the the 6803 MPU can detect bad RAM at power up and do an automatic restore factory settings. That does not happen, you have to do it manually.

Would have been nice for Bally to do some RAM checks at power on. These games cannot handle when audits are set to a value out of bounds what is possible. Usually results in attract mode, but no coin up, no game play, even if in free mode. ie if the current credit value is higher than the max credits value then you get no game start, no coin up, and no warnings.

I noticed Future Spa attract mode displays are a bit inconsistent to the pattern. Sometimes there is blank time inserted between showing the high score to date and the last game played score and sometimes no blank time. Occasionally the blank time is a bit longer than usual. Not quite a bug, just something odd that caught my attention. It is running the Oliver 7d capable version which could matter.

I found a good way to wreck the NVRAM chip contents too in at least some games. If you manage the push the audit clear button after the last audit, and before the game reboots itself. Like if you are speeding through the audits clearing them all out and run past the final audit. The software crashes and next boot the audits are wrecked. Not really a bug either, just annoying quirk.

In a Bally 6803 games like Special Force it is possible to get corrupt RAM that breaks audit mode you cannot fix within the game's software.

With the bad corrupt ram, every time I go into book keeping data it locks up on game percent audit and you cannot advance or back up from that point. Keypad just makes ricochet noises but nothing happens. The issue is clear book keeping is past the problem game percent audit and restore factory settings does not seem to clear book keeping. If you have NVRAM or a battery hard soldered to the PCB you are stuck at this point. You have to remove the battery or clear the NVRAM with an eprom burner or different game and hope it writes to that corrupt spot.

If I thought about it, I would have dumped the problem NVRAM chip before wiping it with my eprom burner.

Considering how finicky these 6803 games are with bad adjustments/audits they should have done something like WMS with a RAM checksum.

I've seen audits with digits skipped in the middle (value higher than 9?) when the battery is off a MPU or the NVRAM has not been formatted. Makes sense the software crash on situations like that if it is a replay value.

Laser Ball - WMS System 6

If you can manage to push the coin door diag button at the exact moment the flasher blinks during attraction mode you can get the flasher to stay locked on. That could scorch the backglass if goes not noticed. Once you make it to solenoid test it will turn off after the flasher's turn and then it blinks as it should during solenoid test. This is similar to how the coin door lockout coil behaves in solenoid test. Same thing possibly exists in games like Flash or Firepower.

Nice, that is a good one. I will try it on the test fixture with different games to see what happens. Might be tricky flying blind with the bonus. I do have a firepower and lazerball setup as well.

the WMS safety blanking circuit is not very good at turning off the outputs when crashes like that happen is why the fuse blew. Ending game on zero probably unexpected possibility and makes the CPU jump out of the software program and then random stuff happens. In that state there is a good chance the display PIA port stays active enough to stimulate the blanking circuit. The solenoid(S) lock on and the power board fuse doesn't always go before the PCB and coil get damaged if it is only one solenoid locked or over fused. The lamps might lock on too. If the lamp columns +18v side locks on the 27ohm resistors start dissipating tons of heat and can desolder themselves off of the board or burn.

Stellar Wars. Test mode special solenoids q2 and q4 are reversed compared to every other game. Both manuals has the solenoid test order listed correctly so not technically a bug, but a quirk and through me off using the test rig.

I can confirm odd stuff can happen if a WMS 6 digit game ends on a million points. What I tried in Laser Ball was to score exactly a million on ball three and then tilt and drain. Attraction mode seems to be running properly but the player one display is counting up by 32,000 every few seconds. I let it go 10 minutes or so and it is still counting up. The next game I started it racked up 64,000pts and seems to be OK after that. Not sure if that happens every time or different if it doesn't end on tilt.