Have 17PW26-3 mains fuse gone, chopper damage and D893 and C931 on the 30V supply blown.... all resistors check OK around the chopper.

I have a 17PW26-4, so in it went and the set worked merrily away. Can anyone shred light on the difference between a 17PW26-3 and a 17PW26-4 power board?

Thanks, Dave.

Thanks for links.

It's worked fine, the -4 board will work in place of the -2 board, I can't say if it'll work the other way round, that is a -4 board being swapped for a -2 board.

Dave