I'm trying to clean my JVC SR-W5U to remove a few horizontal lines of noise in the upper portion of the screen. There wasn't any improvement with the heads, some from getting the black crud off the capstan. There some of that same hard black oxide on the motorized supply side impedance (?) roller, but swiping that side to side doesn't work because it spins freely. How do I properly clean this part without throwing the tape path out of alignment?