300 D window wont go up
 

hey there im a mercedes virgin!!! yesterday i bought a really clean 84 300D (my first mercedes). on the way home the drivers window stopped going up or down. i removed thr door panel and tested the power to the regulator motor with a test light and it shows power on both wires all the time. when the window switched in the up position the test light goes out on one wire and then the same on the other when the button is pressed down. with out pulling another door panel, is it normal to have power on both all the time? previous owner mentioned to never shut the door with the window down or it will go off track. it doesnt look off track. i did remove the motor from the regulator and it did not spin. any help is appreciated.

i thought it was motor time. dang it! i didnt even make it home before i broke it. i dont see any rust at all though. i took the panel off and its clean. do you think the track is just worn. i really dont think its off the track either. i can see up inside and it looks to be in the track. will it fall inside if it comes off track? can i trade te motor with one in the rear? thanks for your help