HP LJ 5100, Tray 1 + 2 not picking up paper

i just changed the pick up roller and spring plate (if this is what its called) for both the tray 1 and 2 on my printer as it was picking up multiple sheets at once. now the paper is not picked up at all. on tray 2 the first sheet moves over the spring, but does not advance. tray 1 does not move at all. there is a clicking sound to the left of the printer: click-click-click, click-click-click- three or four times before i get a paper jam warning, for either tray

also, full disclosure-
during this repair i replaced the fuser sleeve and transfer roller, and the printer now prints fine from tray 3! (the fuser sleeve was shot)

anyone have any idea what could have happened? what i may have done?

thank you- cs

Sounds like one of 2 things -- most likely problem is the separation pad for Tray 1 is not locked in properly, if the pad is sitting too high (not locked down) there is too much pressure & the rollers can't spin.

Otherwise, could be both roller's drive shaft is out of place so gears aren't connecting / turning. Sometimes you can just gently rotate/adjust the shaft to get it and its corresponding gear back to proper position. You may have to actually remove the printer's side cover and inspect the drive gear assembly which turns the pickup roller (different drive shaft for pickup from each tray). There is a gear, spring, & solenoid on the other end of that drive shaft and typically the gear is not lined up correctly.