You have identified what is good, but you know you have a blanking problem. I would start with the normal troubleshooting course of action for the blanking signal. Start by reading section 3.4.10 The "Blanking" Signal at http://www.flippers.info/system6repairpart4.asp

Likely not related, but I would suggest replacing varistor VF1. Closest component to short and new ones are cheap.

I believe you can bybass the variatior just to check that everything is working.
Obviously don’t recommend leaving it out of the circuit.

You can cut one leg of the varistor and see if the game will boot. It probably will. Then, you should replace it. I think it protects the game against lightning strikes and other situations by failing closed and blowing the fuse. Cutting a leg removes the short and will allow the game to play again. I'm not sure what long term danger exists by running the game long term with the varistor removed but someone smarter than me will be along shortly to explain more thoroughly.

He already said all the voltages are good. If the varistor shorted, yes, fuse would blow and you would get no voltage to the power supply. If the varistor failed open, game would still run - you just lose the protection the varistor offers against spikes on the line voltage.

You can bypass a thermistor using a jumper, but that's a completely different device that's wired completely different. This game doesn't use a thermistor. Do not try to jumper across a varistor. You'll let all the smoke out of the game.

As I said, it's likely not related, but it was right next to the short and it's an important component that's $1 or so new.

Thorly is asking about my BK. Thank you to everyone who has responded. I cut the veristor out of the circuit and it still is in the same state. Any other suggestions for a BK system 7 stuck in blanking?
I found a coin switch that may have been stuck on after reconnecting, but have since fixed that. The cpu board was rebuilt and working before this. We checked the 40 pin interboard connector and get continuity for all pins.

As said before, the varistor has nothing to do with the blanking problem.

The blanking signal is controlled by a timer circuit (a 556 in System 3-6 games and a 555 in System 7 games). If the timer "goes off", blanking is set low. When the game software is running properly, port PA2 on PIA IC18 is pulsed every .8 msec. This pulse is fed into the blanking circuit which resets the timer after the signal from PA2 goes high and then low again. As long as the timer is reset before it triggers, blanking will remain high. If the game program locks up or the CPU stops running, then the timer will expire, setting blanking low. The key is the signal from the PIA going from High to Low, the transition is what resets the timer. If the port sticks high or low, then blanking will be set low (no transitions are occurring).

The symptoms of a low blanking signal are no displays and no game controlled lights (which also happens to be the symptoms of almost every other MPU board problem.) If the board seems to be booting with the game ROMs and it passes the self test (both LEDs flash and then go off), check the Blanking signal at test point 4 or pin 37 of the interconnect. It should be +5 volts.

The most likely cause for a blanking signal failure is a timer chip failure, a bad capacitor at C31 or a a failure of transistor Q5 (a 2N4403). In System 3 and 4 boards, the 556 is also used to generate the IRQ signal, so I would suspect C31 or Q5 first. On System 6 boards the 556 is only used for blanking as is the 555 on System 7 boards.

Thank you! How do I check this 555 circuit? Where is it located? I have seen this before on Mark's Guide, but I don't even know where to start checking for issues. I am familiar with the driver board, but the CPU board is new to me. I have a DMM and a logic probe.

95% of the time BLANKING IS A SYMPTOM, not the cause.

blanking goes low when the monitored PIA port is not active. Sure the cap or timer chip could be the cause, but go to the monitored port before ripping out the the timer, if the port is not oscillating, then the blank is going to be low.

Any chance you dumped 120v into a switch or something? I had an accident once with a spool of solder sitting on the cabinet bottom of a WMS game. The game was off but the solder strand touched the hot side of the line filter, kapow, which much be before the power switch.

Hit the line filter, but nothing else. I did notice that a coin detect switch had excess solder on it, which would have caused issues to, but I have fixed that and there is no change.