What lizhsteve was hinting at is the following: the headphone jack has internal switches that open the circuit to the TP's speakers when you insert a headphone plug. The switching is done with a simple mechanical means. When the plug in inserted, it moves the headphone contacts outward, breaking contact with (probably) 2 internal fingers. When it is working right, the headphone contacts touch the internal fingers, closing the L+R audio circuits and powering the TP's speakers. (See the schematic on the lower left on http://www.mouser.com/catalog/specsheets/KC-300484.pdf When the headphone is plugged in, 2 (tip) and 3 (ring) spread outward, breaking the contact between 2 and A and between 3 and B. A and B are what I'm calling the internal, or switch, fingers.)
Your jack is probably bent internally. Either the plug contacts are not returning all the way back to the switch fingers, or the switch fingers themselves are bent.
A final possibility is that the jack has partially torn loose from the motherboard, so that, in the schematic above, A and B no longer are soldered. This is not likely, however.
It would be easy enough to replace the jack IF you have TP disassembly skills and can reach the motherboard AND the jack is a standard one (so you can find a replacement) AND you have soldering skills.
There is a slight possibility that a gentle rotary motion with a wooden or plastic toothpick -- GENTLE so you do not break the toothpick -- might bring the contacts back into operation. By "rotary" I do not meant "twirl," but more like the motion of a mortar in a mortar and pestle.
Dave
T42 2373-K1U
Windows XP Pro
