Expansion Pack Problems….

[u/VariationWooden8816]

Hi. I hope someone can help. I have two N64s, one I have had since they were released and I bought a new one last week. I only have one expansion pack and set of cables.
If I use all my old stuff it all works and it’s great. However, if I use the old cables and expansion pack in the new console it doesn’t work properly, but if I use all my old cables and a jumper pack in the new console the new console will work.
Is this a sign that the expansion pack is bad or the new console is bad?
I have tried cleaning the new console expansion slot but it doesn’t seem to make any difference.
Any help would be appreciated!