Saffy is poorly !

Yep my best girl is not a happy bunny.
(twotrees sapphire pro2)

Started a week or so back and while mid print, she just stops. the hotend and printbed power down and the printhead just stays where it is.
the control seems to think it's still going and has no indication that anything is wrong. apart from both heaters being switched off and nothing moving.

No error messages or anything remotely as useful as that.

Changed sd cards.
Seemed to work at first then same thing happened again.

And it can be on short prints or long prints.

It is NOT every print.

I had a 18 hour tpu print work perfectly inbetween two pla prints that both failed at around the 40% mark (but not exactly at the same point one at 44% one at 42% and one at 40% - I know that's three :-).

I've gone through all the obvious stuff.
It's not the slicer, it's not the sd card. the wiring seems to be sound as everything works right up to the point that it doesn't.

I've been in the room when it happened once, and it just stopped. No noises or any indication of any issue.

But as she runs silently anyway, I do not know if the temps stopped before or after the printhead stopped moving.
As it was all cooled down before I noticed she had stopped moving.
It's the only drawback of silent steppers.
You just don't notice when they stop.

My current feeling is that maybe there is a dodgy wire and that if the thermo or heater wire has a hairline crack in, would the signal dropout - even if it was only a blip, cause the heaters to reset and the print to stop when the hotend dropped beloiw a certain temperature.

Given that the nozzle is also partially clogged and need replacing - it would seem logical to assume that the temperature cuts out and the printer stops when it drops below 160c

I do have a spare thermistor that gambo kindly sent me.

But as I've never had a heat cartridge fail in over 8 years and 6 printers - don't have a spare one of them.

Any other ideas on what could be causing this would be gladly accepted.

It's got me scratching my head.

well it looks like the problem is solved, thanks to gambo :-)

Apparently over time the pid settings somehow start to effect the hysteresis settings and the printer cuts out.
Hysteresis is right - basically she's having a panic attack.

feflash the dfirmware and reset the pid settings - and here's a golden tip for you: when you get a good set of pid settings, save them in a text file for easy access and really quick flashing to the firmware.

So i dropped the original marlin firmware on, ran a dry print (no filament) and the mould that had died 3 times ran all the way through.

So I've put the medellist firmware back today and reflashed my good pid settings and am currently coming up to the critical phase of another dry print.

If that goes through without any issues I'll do a 'wet' print over night :-)

And i changed the nozzle to a hardened steel one I've had gfor a few years and never used. still 0.4.

And i discovered that brass 'standard' printer nozzles are nothing of the sort.

All the cheapo ones I've acquired with bits in the last few years are a smaller socket size than anything in any of my printyers. WTF ????
I can't recall ever seeing a required socket size on nozzle listings.

Bloody weird.