Only left speaker works on X201S

[FryPpy]

Yes. The roots of this thing is going deeper than 6 years. Already i have read this topic but my problem slightly different.

I have transplanted X201s (with i7 640LM LV CPU) main board to X201 body. It accepts NV HSF and become cooler (fan connectors on X201s and X201 is different but connector from X201 can be inserted in X201s socket). Stereo speakers and I/O subcard have been taken from X201 but only left speaker makes sounds. I have installed latest drivers from lenovo site and have tried drivers mentioned on lenovo forums (6NA120WW) - mono sound on X201s and stereo on normal X201 (the same hdd have been transferred to X201 to check drivers issue). After this i have tested 3 X201 thinkpads with Ubuntu 10.14 liveCD on USB. Normal X201 - stereo, X201s - mono.... and X201t with the same pair of speakers can do stereo sound.

Other note - X201s on ultrabase can do stereo in ultrabase speakers.

I have read schematics for X201 and haven't found any NV (X201) nad LV (X201s) differences in audio department. I haven't found any special signals (wires) from mainboard to I/O subcard that can switch codec from stereo to mono behavior.

So i haven't found any differences (between X201 and X201s) in drivers (OS) and hardware (schematics). So the rest to check for differences is the BIOS | EC.

Any thoughts are welcome

[rkawakami]

My thoughts point to the headphone jack on the I/O subcard; I'm assuming that there's one located on the board. Typically there is a 'switch' inside the jack that disconnects the main speaker when inserting a plug. If the switch is stuck in the open position then no sound will come out. You could try plugging in a headphone and see if you get right and left channels in the headset. If you are lucky, removing the plug will allow the sound to return to the right speaker.