That capacitor is installed correctly. There's a white line along the side of the capacitor indicating the negative leg side.
If you look at both leg terminals under the capacitor, the negative terminal will have a hashed face rivet, that's what the "-NEG" writing on the capacitor you're looking at is indicating.

Are you measuring 12 volts at the input of the 5V regulator - measure it at test point TP5 on the solenoid driver board.

no 5v a lot of times is caused by the 12v unreg return wire between the driver board and rectifier board is burnt at either or both ends. its orange in color. Inspect the 20 pin rectifier board plug and top right plug of the driver board.

The "ground mods" on the driver board shown in guides is a band aid fix a lot of times when that wire has gone open circuit but ultimately its a connector issue.

Do you any credits? Drop a quarter or two in thru the coin slot, then push start and see what happens.

BTW - you mentioned you cleaned the connectors on the SDB - that tells me you will need to replace those connectors, since that is only a temporary fix

They call that "attract mode'. 201760 is probably the current high score to date and the 00 is the last game played score.

Sounds like you now have switch problems. Using the test button get into first solenoid test. Check that all the solenoids fire and let the game raise all the drop targets. Then get into switch test and see if the credit and start buttons register. The coin and start cabinet switches go through the right side bottom plug on the MPU.

Also if you have no battery its possible to get a bad value saved into the current credit count audit (#5) that does not let the game start or coin up. With audit highlighted in test mode push the NMI audit clear button on the MPU to reset that audit back to zero. A lot of times its good to go through and clear all the audits if the board had been run with out a battery/NVRAM. These old bally games have no automatic way to detect and clear out corrupted memory.

Did you get into test mode? Now it sounds like you have momentary solenoid data problem.... ie Game wants the outhole to shooter lane coil, but bad solenoid data and you get pops instead.

Check solenoid test and verify the solenoids fire in the proper order, none are skipped or fire twice/out of order. There is usually a card in the backbox or in the manual will tell you the order solenoids go. Nine times out of ten momentary solenoid data problem is related to connector problems at MPU J4 and driver J4. Very common problem. Battery leak wastes MPU j4 and driver J4 gets cracked solder joints.

off topic but chime "extra" ??? I never understood that. Why can't it just be chime 10,000? Is there any game where the extra chime is not 10K in value?

This game
Eight Ball doesn't have any 10k points.
10k points didn't appear till Power Play / Mata Hari, earlier games don't have it.

https://www.amazon.com/HT-225D-Cycle-Ratchet-Crimping-interchangeable/dp/B007JLN93S

If you have a jumper wire - connect one end to ground and touch the other end to the metal tabs on the solenoid tabs. That will tell you if the connection from the driver board to the coil is good.

If you have a logic probe or even a DMM. You can go to the driver board 74154 chip. Using the schematic identify pins labeled A B C D. During solenoid test each one should stay mostly high (5v) but blip low (0v) occasionally. If you see one of those ABCD signals that is always high, that is where you can focus your connector work on.

Don't forget solder joints too. The driver board is typically a single sided board with no plated through holes. Because of that the header pins (driver J4 for solenoid signals) are even more likely to get cracked over time. MPU J4 gets wasted by the leaking battery.

I never realized that. Surprising they added the 4th chime just for the melodies for game start, power up, etc. Love the bally chimes, they sound great. Much rather have the chimes than the first generation sound board which is pretty lame sounding. Bally made a kit to put the sound board in early chime games but I'd almost want the reverse.... a chime box kit to retrofit chimes into games using the -32/-50 sound board.

Sounds like you might have a problem with the solenoid expander board.
If you go to lamp test mode, do you hear the solenoid expander relay at the front of the playfield clicking in unison with the lamps flashing on?

The solenoid expander board is next to the left flipper mechanism. There's a lamp next to it that helps activate the expander relay which effectively switches banks of solenoids.

https://pinside.com/pinball/forum/topic/eight-ball-deluxe-owner-club-guests-welcome-as-well/page/61#post-5639867

Wrong game you had it correct earlier

Assuming we talking about the original 8 ball and not deluxe, solenoids firing twice is a momentary solenoid data problem MPU J4 to driver J4 connector problem 9 out of 10 times. It is so super common that this problem comes up like once a week. MPU J4 gets wasted by batteries and driver j4 gets cracked solder joints is the typical cause.

Put the game in solenoid test. Stick DMM set to volts DC lowest range. BLack lead on ground. Red lead probe driver board U2 Pin 20. Let the game go through an entire cycle of solenoids and observe that the voltage is normally 5v but occasionally dips down close to 0v for brief pulses. Then repeat the same test on driver U2 Pin 21, 22 and 23.

The signal that stays at 5v always is the problem. Report back which pin stays high always.

Shotgun fix is to repin MPU j4 and driver J4 both the male and female side and maybe replace MPU U11 PIA and its socket.... but its probably the connectors and not mpu u11.

Doh!

Did you also re-pin the connector J4 on the solenoid driver board? That connector's at the other end of several of the wires carrying the data signals coming from J4 at the mpu.