I remember when I got my Picasso IV (or was it the Picasso II before that?), the 4000 used to lock up occasionally and I was advised to upgrade the Buster.
Since I did so back in 1994, I've never had a lockup since.
To be honest, I can't remember whether it was the PII or the PIV, but the bus circuitry is probably similar. I'm sure that if you upgrade your Buster, the problem will go away. It's a well known and documented problem.
tony
