Quoted from ApplePie:
So I'm currently going through the process of identifying what is working properly and what is not working properly. In the working properly category, the pin appears to boot up to attract mode with playfield lamps flashing away and the occasional synthesizer sound emanation from the sound board (not sure if this is normal or not).
Yes, the a random sound effect will play every 9 minutes or so.
2) During attract mode, the "right outlane special" lamp and the "1 can play" lamp on the backbox are locked on and do not flash (both of these are on lamp drive column 7). The remainder of the lamps on column 7 do not light. When I run the lamp test via the coin door all of these lamps flash as you would expect. Is this normal behaviour?
Yes, normal, the stock attract mode on williams system 6 games only includes the first 6 columns of lamps to save space in the code (although they didn't really need to in most games). It just has a set of lamps to copy each step so I guess over 40 steps or so, saving 1 byte per step saved them 40 bytes. This has been fixed in various rom mods.
3) In the solenoid test, it appears that all of the solenoids fire except the top left pop bumper. I'll double check the solenoid wiring under the playfield before chasing this back to the driver board.
Try going into audit/test and just activating it via the skirt. The solenoid test uses a different path to activate the special solenoids.
5) I went through all the options on the menu and set number of credits in #18 to 0 to get into free play mode. Also adjusted a few of the others to what I think make sense for starters. Are there any suggestions for any of the settings from fellow Firepower owners?
You might not like the way the freeplay works - no credits added or subtracted, ever. But at least you can set the credits to 01, then set the freeplay option, so it always shows at least 01 credits for a show or something. Again, rom variants available that fix this to some other way so you can still chase winning credits.
And finally, I'm not certain that any of the errors I've identified so far would prevent a game from starting, unless a stuck switch would do it. So, that's possibly going to take some work as well.
Firepower needs to see 3 and only 3 closed switches where a ball would normally sit to start. The 3 switches have to come from 4 places - left, middle, and right ball trough, and the shooter lane. If all 4 are closed, the game will not start. It will also not start if you have the left trough closed and the shooter lane. The stock software has some good multiball handling code (although it's not perfect) which for the very first solid state multiball game turns out to be pretty solid.