N64 Controller and Adapter with Project 64

[KingHarkinianZC]

Hello. I have been having problems getting my original grey N64 controller to work with Project 64. I ordered the controller off of ebay a few days ago. The description said that the controller's stick was tight (which it is), and working just fine on a real N64. When it came, I plugged it into my Boom N64 and PSX USB adapter, and went into control panel, and calibrated it. After doing so, I tried setting the controls in project 64. I found that moving up, down or diagonally is impossible. Checking in control panel, I found that moving in those directions causes it to think I'm jerking the stick back and forth between that direction and back toward the center rapidly. Also, the Z rotation goes crazy. What's even stranger is that all the buttons work, and so does moving perfectly left or right.

I don't think the stick is broken. It only moves a tiny bit (like a 1 milometer radius) when the controller is shaken, so it most definitely not loose. Could this controller just not be compatible with this adapter (which is known to only work with specific controllers for some reason)? Would buying the Mayflash one work? I'm not sure what to do. Can someone please tell me what to do? How can I check to see if the controller isn't broken, and should I just buy a better, more reliable adapter if the problem is in fact the adapter?