you can probably order the part directly from AKAI.
check about three or so threads down from this one whould be a parts list Thread find your part number and give AKAI a shout and while your at it cuss em out too for putting out sh*tty products
other than than you can open up the machine yourself and see what kind of part you need.
i almost replaced that part on my 1k but ended up selling it before it completely crapped out. it worked just fine but you had to wiggle it sometimes.
to the OP it looks like your problem is more than just the output itself if you are having problems with both your left output and headphone left out. you might need to replace the PCB board that connects the two?????
all other either check the parts list or google it as im not sure what the part it is called but it shouldnt be too difficult to replace just a pain in the a$$.