On Mon, 3 Feb 2014 15:20:07 -0800, "David Farber"
wrote:

Initially there was a paper jam from the paper tray 2 which is the drawer
that slides into the bottom of the printer.

Replace the feed roller RB1-8865 located above tray 2. If my
guess(tm) is correct, the printer has never had any of the rubber
parts replaced. Considering it's age, you might as well replace ALL
the rubber. Cheap enough:
http://www.ebay.com/itm/320746402020

The other malfunction
is that the pickup rollers for tray 2 are activated even if there is no
paper in the drawer.

Congratulations. Your printer also has the HP exclusive sticky
solenoid problem. How to fix it on an HP2200, HP2300, HP4250, etc.
http://www.learnbydestroying.com/jeffl/hp2200/hp2200.html
http://www.learnbydestroying.com/jeffl/hp4200/hp4200.html
Unfortunately, I haven't bothered to make a web page for the HP4000
series printers. It's similar to the others except that the solenoid
is buried under additional layers of metal plates. I suggest you take
photos to help with the reassembly.
http://marketpoint.files.wordpress.com/2011/03/lj40004100-025.gif
Tear the printer apart. Find the sticky solenoids. Clean off the
sticky goo from BOTH the armature and solenoid core using solvent.
Apply thin felt as shown. Demagnetize the solenoid core if you
suspect that it's magentized.
http://www.learnbydestroying.com/jeffl/crud/hp2200-solenoid.wmv
Put Humpty Dumpty back together again. Be sure to thank HP for
ignoring the problem since the earliest HP laserjet printers.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558