Thanks for your help. I have it sorted now. I didn’t have the data sheet, but have it now from JNX. your advice really helped. Negatron component side faces the right side of the JNX adaptor as it plugs in to the Jamma board.
In terms of inserting the negatron, which way should it be inserted in header CN2? Negatron component facing the voltage meter or away from it? I don’t want to insert it wrong and it looks like you can insert it both ways.