I would check Ebay for the belt. As for the instructions, I would first recommend trying to find a repair manual, seeing as how information on self servicing seems to be limited. I found a couple videos that help a little bit on YouTube. I have changed the clutch drive and the mother board on mine. I have had to just "feel" my way through it because I can't find information for either and I can't find a manual.HP is no help at all with these models because they have been discontinued. When I asked them for where to find the clutch drive, they told me to buy a new printer! I finally found a clutch in China. I looked for a couple weeks here in America, to no avail. The clutch was $18. I found the mother board on Ebay. The original mother board was fine, I broke a piece off and couldn't repair it, so I had to buy one. I wish you the very best of luck.
Melody