Originally posted by Postblank:
holding down store while powering up. That allowed me to play the 00 patch but went back to soundless once I changed patches.
Well at least that would seem to indicate that the audio electronics are working fine so that is a good sign that you have at least heard audio from it.
You probably should change the internal battery. Do you know how old it is? Maybe that is causing the internal patch data to be lost which could result in no sound.