Service Manual
Page 210
... all of the paper is jammed in all trays and replace trays as needed. Replace tray 3. Inspect the pickup rollers in duplexer (HP LaserJet 2300d printer, HP LaserJet 2300dn printer, and HP LaserJet 2300dtn printer), check the duplexer area. Replace the tray with the defective pickup assembly. For both trays, slide the tray back into place. Check the paper-feed and rear-output areas...
... all of the paper is jammed in all trays and replace trays as needed. Replace tray 3. Inspect the pickup rollers in duplexer (HP LaserJet 2300d printer, HP LaserJet 2300dn printer, and HP LaserJet 2300dtn printer), check the duplexer area. Replace the tray with the defective pickup assembly. For both trays, slide the tray back into place. Check the paper-feed and rear-output areas...