Extruder keeps stalling
My Mk4/MMU3 is about 18 months old. Recently prints started failing in random places. The extruder just stalls and the machine carries on as if nothing is wrong.
I've tried adjusting the idler tension. I've also tried it without the MMU. I'm currently running it without the nextruder cover so I can see the gears stop when it stalls. When it does stall, I can briefly unlatch the idler and it will start extruding again. Then it will stall again a few minutes later. If I go into control/Move Axis/Extruder it seems to extrude normally without any effort.
So I'm thinking either the stepper is weak, or the board isn't supply enough power. Can anyone suggest how I can troubleshoot this?
RE:
I've found the reason for this now. The nextruder fits inside the nextruder heatsink. There is a close fit around the diameter. Maybe the heatsink has changed shape? When I look at the inside of the heatsink where the nextruder rotates, I can see scoring has taken place. The idler is mounted to the heatsink. So when the idler is latched, the tension in the springs is pulling the heatsink against the nextruder and clamping it. I've had some pliers on the stepper shaft. There is plenty of torque being produced. So my problem occurs when the nextruder is clamped against the heatsink by the idler springs.