I've done a search and looked at the various guides, but none can answer my question.

I recently changed out my analog stick as it was jerky and uncomfortable to use. I bought one off ebay, switched it out no problem. When I started my PSP up I could only use up and down, left and right wasnt recognised. Made an enquiry to the seller on ebay that it might be faulty so he sent me out another one. This one only recognises left and right movement, no up and down. Grrrr!! And I no longer have the original to put back in to test it's not something else wrong.

Anyone have an experience with this sort of issue before?