Problem with CD player

Okay, as stated before on here.
I have 4 cd changers that skip within the first
30 seconds of a track.
Now, some on here have said to get some
White Lithium grease from the hardware store, and lube
the guide rails for the laser assembly,
well I finally did that on Saturday.
It did take awhile to figure this out because the guide
rails were NOT at the top, as some said on here.
My cx90es chagers have the guide rails, in the back
corner, in the middle, and you have to use your finger
to move the gears that move the rail.
NOW, so far so good, NONE of them have skipped!
So that was HELPFULL advice.
NOW, the problem is 1 of the changers only has sound
coming out of the ANALOG LEFT channel,
NOT RIGHT ANALOG channel.
HOWEVER, I GET STEREO output from the OPTICAL OUTPUT!
I checked the board, and nothing seems to have come loose
or broken! The Female connector, seems to have a
BIGGER opening than the the left female connector!
So, can I stick tin foil in the female connector to see
if it`s just making contact? OR, is it something else?
I cleaned the laser, when I had the unit opened, and
since the Digital output is in stereo, what else
would/could it be?