Why won't my new disc drive read?

After purchasing one of IFixIt's new disc drives and installing it, the disc spins upon startup and then stops, followed by the unable to read disc error. At first I thought it was because I didn't reset the Wii before inserting a disc, but I tried that too with the same result. I'm no expert (have only refurbished two yardsale Wii's in the past), but all of the solders and wiring seems secure, and I can't find any bent or broken pins inside of the connections. While waiting for the disc drive to arrive, I also replaced the thermal pads and gave the entire console a good clean. Could there be something that's not in the disc drive that causes a disc read error?