Coils don't "wear out" so swapping the knocker coil to the kickback didn't really do anything. When you moved it did you leave the lugs on the coil pointed up, so they contact the underside of the apron? Ditto for the outhole kicker if you messed with that at all.

The logical direction is to reverse everything you did - despite your best efforts with pictures, etc. you've got something wired incorrectly. For instance, if the diode on the coil happened to be mounted the other way and you were keying off a logical path of "this wire was on the left lug" you would have reversed the hookup if the diode was the other way round.

The weak coils are most likely from dirty coil sleeves, worn mechanisms, old lubricant on mechs (most of them DO NOT need anything, and the ones that do, use VERY LITTLE. Do NOT use WD40). You could also have a low voltage condition in your location, or the transformer could be wired wrong, the bridges could be bad/weak, the connectors on the power supply, a compromised wire in the power chain.

Sounds like you wired a coil with the diode facing the wrong direction. The red power wire should be on the banded side of the diode. You should recheck all your wire connections regarding the diodes and make sure no coil lugs are touching anything. You now probably have a issue on your circuit board that is not expensive to fix but might be above your level. You might fill out your location on your profile and maybe someone local can assist. I will attach a picture showing what I mean about the wires and diodes. The black diode has a silver stripe at one end. That stripe should be facing the lug/wire as shown. Get your wires/diodes correct and report back.

IMG_5079 (resized).JPG

It's a long read but you should check out these 2 threads. One about Williams system 3-7 and the other about flippers. Your flipper issue is probably dirty worn parts and your end of stroke switches.

https://pinside.com/pinball/forum/topic/vids-guide-to-bulletproofing-williams-system-6

https://pinside.com/pinball/forum/topic/vids-guide-to-upgradingrebuilding-flippers

At this point, check your power supply voltages. Also, are there switches on the Rottenfog that are supposed to be set? Are they set for the correct machine?

There are several threads here on how to use a multimeter, or go to Utube and look - tons of them out there, too. Learning to use a multimeter is fairly easy, and a "must know" if you're going to own/work on a pinball machine.

When you say you got nothing, please elaborate - no lights, no sounds, some lights, some sounds, etc.?

Ok simple stuff first. Are the connectors on properly on the new board? Have you checked your power supply voltages?