Hold switch/headphone jack not working even after replacement

I recently replaced some parts (battery, click wheel, color screen) in my ipod classic. Afterwords, the hold switch no longer worked, and the headphone jack only worked on the left channel. I ordered and installed a replacement hold switch/headphone jack, and it still has the exact same problem. Any ideas?

I've spent about $100 on parts for this ipod over the last few months, and I'm hoping to fix it, because there honestly isn't anything on the market that has the same disk space (160GB) and lack of extra features I don't want (camera, internet, video).

Please help!