Check you fuse under the playfield near the flippers with a meter.

I think the knocker is not fused at that location.

1 amp slow blow fuse beneath the playfield

Confirm to see if you have voltage at all coils/lugs when the game is first powered on.

Put the black lead on the ground braid in the cabinet and the red lead on each lug on each coil under the PF to check for DC volts. Yes, you can test either lug, they should both have voltage just like @ the knocker coil. Remember, a coil is just a long piece of wire.

It is possible that you have a bad solenoid driver board. But let's first confirm your voltage at the coils on the playfield.

The knocker is firing, I'd verify there is power at other coils first or manually try to fire them by grounding the tab on the drivers.

Even if the fuse is good, check the fuse holder and replace if necessary. Those playfield fuse holders wear out and stop properly gripping the fuse.

Next step is to verify you have 43v. Take out a meter and measure the voltage at both sides of the fuse holder then trace backwards to the rectifier board. 43v leave the rectifier on a brown wire, J1 pin 7. It goes to the fuse holder then out on a yellow wire.

What is the voltage after the playfield coil fuse? If power is making it through fuse I suspect the first coil in the chain the bus wire came off.

Not familiar with Fathom but I had the same problem on a SpeakEasy-4.

The 43VDC relay (under the playfield) was faulty (not sure if this relay is also on a Fathom expander board)
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This tells me you may not be testing for DC voltage properly or, your ground braids are possibly not connected between the coin door, cabinet, and backbox. See post #5 for testing procedure. All the coils gets voltage from the same DC supply rail and should always match (IN A BALLY GAME). Remember for testing purposes, always use the ground braid for your black meter lead when testing for DC coil voltages.

You can also test for voltage at that relay under the playfield if you suspect it's having a problem. The one on my game has it's leads labeled on the PCB. They are notorious for having cold solder joints. Speaking of that relay, it requires a working incandescent 555 bulb next to it to function properly. Lamp (or socket!) could be faulty if it's not clicking during your "all lamps test". (The one in my Fathom was never even grounded properly at the factory.) The relay itself could also have issues. Sometimes you can remove the plastic cover on them and clean the leads with ultra fine sand paper to get them going again but I would refrain from trying to adjust it unless you are familiar with using a proper pinball "switch adjustment" tool.