Hi Bernie
Try using better quality (Better shielded, lower resistance) cables, and make sure they are Midi cables, not just ordinary 5 pin Din cables.
If the above fails, you could try a Midi box (Any will do) between your Nord & Technics, which has its own power supply, as this will make sure the Technics is receiving a full signal. (The G70 Midi chip may be more sensitive than the Technics)
Hope this helps

Bill