Imp v2 + MC Cthulhu + RJ-45: Doesn't work on PSX or Gamecube

Dude, I already tested all that. In my first post, I already mention in my first post that I tested the connections between the MC and the Cthulhu with all 8 columns connected and fine. Ditto between the Imp’s column holes and the RJ-45 jack (post #3), they all come out working as okay. And my cords are just fine, none of the wires are broken on 'em. I don’t what’s going on that would cause both the D and the V columns to go dead when I have a PSX or GC cord plugged in, but be connected just fine when I use my USB cord instead; or for the F column to be connected fine from the Cthulhu to the RJ-45 jack but be dead when that same GC cord is connected.

General train:
(Cthulhu)–(Imp)—(Imp’s RJ-45 jack)----(internal cord RJ45 end)—(internal cord RJ45 end)—(neutrik inside jack)----(neutrik outside jack)----(console cord RJ45 end)—(console cable end)

Specific for PSX ACK line; modify as neccessary for each pin you’re testing.
(Cthulhu Col F)–(Imp point labelled F)—(Imp’s RJ-45 jack pin 7)----(internal cord RJ45 end pin 7)—(internal cord RJ45 end pin 7)—(neutrik inside jack pin 7)----(neutrik outside jack pin 7)----(console cord RJ45 end pin 7)—(PSX cable end pin #9)

There’s your chain. Forget the fact that there are up 8 trains to deal with, just deal with one train at a time. The one going from the PSX pin #9 (ACK) to Cthulhu column F would be the one I’d suggest starting with. You know in order for things to work, that spot on the Cthulhu, column F, needs to be directly connected to that pin on the end, and according to your post, it isn’t. So there’s is one or more breaks in that chain. Lucky for you, multimeters may not be able to tell you where the break is, but they can tell you when they are not broken.
Each of those spots in parenthesis are spots you can put one of the probes. Each one of the lines connecting them are spots where the connection can fail. Use process of elimination to determine which sections work, and which ones don’t. The physical connections between RJ-45 and jack is also a possible point of failure, which is why they have lines along with the cables themselves.

Okay, so took apart my entire stick and tested connectivity of where the F column would go. The Neutrik jack and the internal ethernet cord all tested as connected. But - contrary to my previous test, the Imp’s connection between it’s F solder spot and line 7 on it’s RJ-45 jack does not show up as connected.

This same exact thing happened to me. Turns out the 7th wire was sliced when I stripped the sheath off the rj45 cable for the imp-neutrik. Damn you white-brown/white and thanks Toodles!

This happens to me every once in a while. I usually just start over or redo the part with the issue from scratch.