Hey guys and gals. I did manage to repair this myself. Parts were about $85.
I had a snag in that I was sent the wrong parts ( for a 540) so that caused a delay, and I was pretty pissed about that. " Cause I had my machine all apart, ready to install the new stuff, with the disassembly fresh in my mind..I find out - wrong parts..another week before correct stuff arrived and the re-install didn't go as well as I would have liked, but I got'er done. While I was at it, I changed to the new pump, upraded firmware and the MAX inks thing.
If you need details from my fading memory of this process..ask. You WILL need a magnetic phillips screwdriver... My tech guy was a good coach over the phone.
Cheers!
Ken