Road Kings has two sets of flasher bulbs, one in the Chariot and one on the bikers. The Bikers flasher is listed as solenoid 15C, driven by transistor Q14. I know that transistor Q14 works, because Solenoid 15C is the drop target reset, and that fires off without a hitch. I know the sockets aren't bad because I've swapped them with the Chariot sockets, and they work fine there, while the ones now under the Bikers stop working.

I've traced a bunch of wires all over the place, starting from 1J12 Pin 8 on the Cpu board all the way to a board under the playfield with two columns of diodes in reverse directions. I assume this is part of how the A/C select relay functions. Current presumably flows one direction or the other on the the diode board depending on if the A/C relay is energized or not. I've tested all the diodes on this board with a DMM in Diode mode, and the same tests performed on the known good diodes also work on the suspected bad diodes.

The only thing I haven't tested 100 percent is the two resistors that sit in line with the bulbs in question. These two resistors sit on a board with two other resistors that drive the Chariot bulbs. If I'm right, the only real way to test these resistors is to remove them from this little mini board, correct?

Can anyone give me some ideas on what else could be the problem or how else I can troubleshoot this? It's the A side of an A/C controlled solenoid driver, and all wires and connections appear to be intact (as far as I can tell).

Do resistors stop conducting or do they stop resisting when they fail?

I pulled out the two resistors that lead to the Biker Flash Bulbs and tested both of them. They both read what they're supposed to, 5 and 330 Ohms.

I'm looking through the manual and I'm still a little unclear about how the A/C relay system works. Perhaps there's something between the select relay and the lamps that's broken, since the C side of the relay works fine.

In case I need to replace the A/C relay, the manual lists it as part number 5580-09555-00. I can't find anyone that sells this relay, but Marco has 5580-09555-01, which is used in all kinds of System 11 games. Would this be a suitable part for Road Kings?

I had to troubleshoot the flashers under the lightning bolts and learned about them being wired in series. I don't recall seeing anything wrong with the wiring for the two biker lamps, though. I'll double check. I know the bulbs and sockets themselves work fine, as I've done a bunch of swapping around with known good components. Maybe I missed something. I hope it's that simple.

I'll take one of everything, please.

Actually, I have a question for you. Go here!

https://pinside.com/pinball/forum/topic/road-kings-ramp-latch-solenoid

As a last resort, I replaced all four flashers in the back box and re-soldered sockets to their wires, and that worked. Sometimes, all it takes is a metaphorical kick in the cabinet to get things working again.