I took my 650 back to the Sprint store with the common complaint that the headset jack only plays one channel and cuts out the mic. After they recieved a well earned "don't irritate the customers by telling them not to use their Treo as the wonderful MP3 player it's ment to be!" speech, they were fairly cool about ordering me a new one on warranty, and it should be here next week. But... after I got home I got to thinking about things, and if you open the battery case and take the battery out, both ends of the Jack socket are open to air. I cleaned it out with a pipe cleaner and then used a fine dental probe to prize up the outermost and innermost contact bands a bit. Now it works just fine!! What should I do now? Should I go ahead and accept delivery of the new one and hope for a free upgrade to build B on the new phone, or should I just leave well enough alone since I've never had any other problems with it at all? Has anyone ever used this fix and if so, how long did it last?