Hiccups on 3HC expansion board

[jay_s_uk]

@deckingman
It's not at the end of the print, its mid print.
And I use the same sliced files on all my other machines which run duets

[deckingman]

@jay_s_uk Perhaps you have a blocked, or partially blocked nozzle, causing the extruder to skip steps on extrusion moves but not on retraction moves? I've only done limited printing with my experimental hot end, but I can't replicate your problem.

Edit. Try disconnecting the filament from the hot end and run that print again to see if you still get hiccups.

[jay_s_uk]

@deckingman
I'm running a print now without filament and I'm still getting hiccups

[deckingman]

@jay_s_uk What does extruder movement look like? Normal or erratic? Can you upload the gcode file somewhere and post a link to it. I should have my machine back together soon so I can try running your file and see if it gives me the hiccups too

[jay_s_uk]

Hmm, I've swapped from driver 1 to driver 2 and the problem has gone away.

[deckingman]

For info, I've just finished a print of about half an hour, ran an M122 part way through and another at the end - no sign of any hiccups

[jay_s_uk]

Ok, the issue is still there after swapping drivers so ignore that

[dc42]

I'm sorry for the delay. The new firmware was affected by a chip feature that didn't cause a problem in a debug build but did in a release build. It's taken me more than half a day to track it down and fix it, and now I need to review and remove most of my earlier attempted fixes. I should have a beta tomorrow.

[jay_s_uk]

@dc42 no rush

[dc42]

I've put a binary of the new EXP3HC firmware at https://www.dropbox.com/s/7rqp6pul9ip3yam/Duet3Firmware_EXP3HC.bin?dl=0. Please monitor it carefully when using it, it's had only a little testing.