HP4000 Driving me Nuts~

[Fast Response Service]

Hey I have a new problem on a HP 4000 I brought in the shop thats driving me Nuts! Maybe some of you Brite techs can help me figure it out.

as soon as you plug in the power cord the 4 D P/U rollers start flippin and the paper feed roller starts trying to feed no matter if a cassette is in there or not. It will finally iniatialize and come to ready state then say tray 2 is open. Duh!

I have another 4000 Im using to swap parts from thats working. Ive tried replacing the Engine controller, Main motor, does it even if the formatter is out or in. I did notice it stops if I un plug the paper feed assy right below registation assy. but question is? why? why should that have anything to do with the solonoid firing from the cassette? I also unplugged the PCA board in the cassette but it made no differents.

anyone have any thoughts??

[MichaelTech]

Is the MP tray trying to pick up? Check it's solonoid flapper.
Do replace the paper PCA. Check the flapper on the solonoids for the trays.

[Fast Response Service]

No Mike the MP tray isnt trying to pickup, and the cassette D rollers you can put your hand on them and the solonoid is stopping them then firing again to release them, after the printer does its initial warm up cycle it comes to Ready state but if you print anything , say a config page it all starts again, the D rollers fire come to stop the fire again come to stop fire again come to stop ect.... as I stated before, if I unplug the connector that goes to the paper feed assy, rh7-5171-000 the D rollers dont go crazy??

[Fast Response Service]

Its Fixed!!
I got another 4000 and replaced the cassette base, the gear train assy is damaged somehow? havnt tore it apart yet to find the culprit but the new Cassette base works fine.