Is the rest of the machine working? Usually the resistors get hot because the CPU has locked up and isn't strobing them. Do they still get hot if you unplug the connectors going to the playfield lamps from the board? That would rule out the playfield as being an issue. Did they work before?

Some reference material:

http://www.pinwiki.com/wiki/index.php?title=Williams_System_3_-_7

Generally when *all* of something stops working it's a blown fuse or loss of operating voltage (bad power supply connector).

I would first check the controlled lamp supply for correct voltage (unplug 3p4 from the driver board, check for +18VDC at F3 on the power supply board)

Check Q63-Q77(odd) column drive sounds like might be stuck on.

What is happening is the lamp column drivers are stuck on. This rapidly fries those current limiting resistors.

some of the likely possible causes....

CPU is locked up
Interconnect issue (pull up resistors on driver will pull lines high if the interconnect is open circuit, if its A12+, it can muck up the PIA chip selection without locking up the system)
7408 chip that selects the lamp PIA is bad (can get damaged when a special solenoid circuit is burns)
The 7408 that combines the blanking signal and the lamp pia column is bad (floating 7408 lamp column output makes the predriver stick on)
Lamp PIA is failed

Pull the lamp fuse/connectors for now. Power up the game and check to see if everything else is working.