Yamaha APX-10 preamp problem

[robin watson]

Just picked one up (incl a hard case) for $300. I had an APX-6 before, but this has a much better playing feel (great neck - like a Les Paul) and the choice woods give it a decent (though not outstanding) acoustic tone - light in the bass, but otherwise nicely balanced. The light weight, cutaway design is perfect for acoustic gigs.

I wasn't expecting this to compete with a friend's Fishman-fitted Martin dreadnaught, but the tone shaping capability of the on-board pre is very nice, and indented controls lend a touch of solidity to sound setting.

BUT....I suspect it's just a poor connection inside somewhere (there are a LOT of connectors in there!), but I have noticed a weird, intermittent, 'knocking' sound from the electronics. The battery's strong. Anyone come across this problem before?

APX owners, anyone?