It's the CABLE. Tonearm wiring is very, very thin, and damn hard to make connections with.
You "new" wire is probably loose at the cart/wire interface, where the wire is clamped into the clips that slip onto the cart pins. I would inspect those clips very carfully... I bet the wiring on one clip is not done very well.
You "new" wire is probably loose at the cart/wire interface, where the wire is clamped into the clips that slip onto the cart pins. I would inspect those clips very carfully... I bet the wiring on one clip is not done very well.

