I checked the NVRAM and set it to 3 or 5 balls. The value is still correct after cycling power (using a NVRAM module), but it keeps kicking out the ball, incrementing the ball in play forever. I don't know what is going on. Other settings in the NVRAM are OK (high score, accounting, max credits etc), except I also can't get the background sound to play (all 5 sound solenoids fire while running diagnostics).

I have the GREEN ROMS (blown from pinwiki) and have the "adjusted" cheatsheet for the settings so I'm sure I have the right addresses... this is crazy. Could there be something strange with the ROMs?? It plays good, displays are good....

Humm... it's a system 4 MPU. Maybe that's the issue? I'll blow some Yellow ROMs and see how that works too. I think I have tried both locations, but I'll try again tonight. thanks

upon further research, I found that the Yellow ROMs were the older bipolar PROMs and not something you can program in the 2716's. Also, I didn't see anything online that would signify any differences in using the GREEN ROMS in either System 4 or System 6 boards. I just retry the settings and see what happens.

thanks - I did the CMOS reset but that didn't change the effect. I have an original ROM in the sound board. I programmed the Sound1 ROM, but I need to mod the board to have it work. Maybe the original ROM I have didn't have the background sound? there wasn't a label on the part. I guess I'll mod the board to use the 2716 SOUND1 ROM and see if that works.

double checked the settings for number of balls and background sound. setting 30 to 3 (balls) and 31 to 1 (bkgrn sound) didn't fix anything. Trying them at 31 and 33 also didn't do anything. Ran a memory check from test rom on the nvram and it passed. Did the same for the sound card and all 31 combinations make sounds - I heard the normal background sound and the increasing frequency sound, so I think the sound card PROM is good.

this is really starting to drive me crazy! I tried 4 player and it sequences to each player, but keeps play after 5 balls. I thought it could be a stuck extra-ball condition, but since it sequences to the next player each time.

I do have some playfield switches that are not working, but they don't close - they are not stuck closed. (side drains and most of the drop targets) and I don't know how that could impact this issue...

I wonder if I have some bad ROMs? I'll download another from a different site and see if they all compare...

I ran RAM1 and the CMOS test ROM which all passed. All the values I set in the CMOS via the built in diagnostics work - the values (high scores, max credits etc) all are correct and I can read and write to them successfully.
I was wondering what addressing scheme they used in the CMOS - I"ll get the edit_cmos ROM blown tomorrow and see what it shows. thanks!

back in the 80's, when we designed electronics at work, we used a 2kx8 battery backed up SRAM during development. That way we could dump the memory and see what are the variables were when the system crashed. It was pretty cool debugging trick back in the day of 8" floppies and Intel 80xx series processors!

System 4 MPU just has 2 RAM ICs.

Made some unintentional progress on my FLASH. I powered it up for the first time in a month or so to run the "edit_cmos" test ROM and when I powered the game, my displays were all blank... crap! digging around, I found the "displays" test rom and tried that and still no luck, but noticed that i bent some pins on the EEPROM. The way the board is mounted, it's impossible to see the left side of the IC due to the door and hinge.. great!.
Checking the display board, my 5V was only 0.5V. It turned out my ground wire from the power board to the display board was intermittent. Looks to be an issue at the power board molex connector. I fixed that and put the game ROM back in and powered up and all came up good (whew!) and when I started, I got my background sound!!!! I have no idea what caused that to start working... I'll have to start wiggling harnesses and such while it's working and see if I can locate the culprit.

I started to rebuild the drop targets as they were not being detected. Once that gets done I'll see if I can figure out the unlimited ball issues.

At least it's warmer now so i can work in my garage/gameroom a bit more comfortable!

Oh, make it out to the Texas Pinball Festival yesterday - over 400 machines - what a blast! Fun to play the old and new games for the afternoon