X200T no sound from speakers

[jihe]

I am running windows 7 ultimate and had a really strange problem yesterday when I lost
sound from speakers for no apparent reason. Everything is working as it should and there
is sound from headphone. Mixer is showing audio being play but just no sound from speaker
at all. It seemed like broken speakers. I fiddle with the laptop for ages, restarting multiple
times for no avail, until finally I hibernated (I only ever suspend) and miraculously sound
came back upon resume. I am just sharing this for anyone else encountering this glitch.