PSOne audio/headphone jack issue

[Havryl]

Hey all,
I have been 'testing' out my PSOne screen for about 2 weeks now. [By 'testing' I mean playing games for hours]. I've been using the mini av-in jack in the back of the screen for input.
I put in the headphones in the headphone jack [duh] and I only get the left channel in the left speaker of the headphone. I was wondering if anyone else has dealt with this sort of problem before or if this is how the headphone jack is supposed to work for the PSOne [I really don't know]?

While ideally I would like to keep the original headphone jack for use in a portable, if there isn't anyone who has dealt with this sort of problem before I am going to replace the jack. I read the sticky for the PSOne screen and there are leads for headphone left, headphone right, and a headphone switch. I just want to clarify this - In order for the speakers to work the switch lead must be wired with the headphone left & right leads. If not, then the audio goes to the headphone leads, right?
I was planning on using a 1/8" three-conductor jack with a closed circuit so that I can turn off the speakers when my headphones are plugged in. Let me know if this is correct or if I'm completely bonkers and have missed something.

Also: see this link on jack plugs.
http://en.wikipedia.org/wiki/Jack_plug