Therman Runaway - MK3s
Hello,
halfway during a print my printer gave the alarm "Thermal Runaway". The bed is warming up perfectly but the hotend is not doing anything. I've done several guides from the helpdesk / FAQ and have done:
- Standard readout of Bed = 25 degrC; hotend 22 degrC
- Preset preheat PLA or PETG: Bed warms up, nozzle does not.
- Manual heating up (setpoint 60 degrC): No change
- Cable wiggling and movement hotend: No change
- Checking connections of the hotend and thermal resistor: OK
- Voltmeter checks
- Link: https://help.prusa3d.com/en/article/multimeter-usage_2117
- Checking resistance of hotend: 13.6 ohm
- Checking resistance of thermistor: 113kOhm at 21 - 22 degrC
- Voltage hotend heater when warming up: 0V
- Powersupply check below PSU: both pairs 24V DC
- Checking fuses:
Is there anything else I can check? (I'll try later to check directly on the pins without the cable plugged in.
Looks to me that or the connection socket from the Einsy-board towards the hotend cable is not making connection or a fault between the board itself and the socket (loose soldering)
- Prusa MK2 upgraded to MK2.5
- Prusa MK3s
- Ultimaker 2+
RE: Therman Runaway - MK3s
Have you taken this up with Prusa? It seems you've reduced it down to a physical problem at the board. I don't do board level repairs on my printers and I don't think many of us do. Use the Prusa support chat feature, it's quicker than email. They're in the best position to help with something like this. We're going to be more helpful when it comes to getting good prints from a properly functioning printer.
Cheers
-Bob
Prusa I3 Mk2 kit upgraded to Mk2.5s, Ender3 with many mods, Prusa Mini kit with Bondtech heat break, Prusa I3 Mk3s+ kit
RE: Therman Runaway - MK3s
Have you taken this up with Prusa? It seems you've reduced it down to a physical problem at the board. I don't do board level repairs on my printers and I don't think many of us do. Use the Prusa support chat feature, it's quicker than email. They're in the best position to help with something like this. We're going to be more helpful when it comes to getting good prints from a properly functioning printer.
Cheers
-Bob
Thanks, will do !
- Prusa MK2 upgraded to MK2.5
- Prusa MK3s
- Ultimaker 2+
RE: Therman Runaway - MK3s
You say that both power supply pairs are at 24v below the PSU, which is good.
Did you check the other ends at the Einsy? It should still be 24v at the Einsy terminals with the system trying to heat the hotend... with the system idle, you might get an ok reading which could change under load.
¡no entiendo Español!
Nein! Nicht Versteh!
Я немного говорю по-руÑÑки но не очень хорошо, и...
I'm not very good at English either! Maybe someday I'll find a language I'm good at?
RE: Therman Runaway - MK3s
Thanks for the suggestion !
Yes, directly under the PSU and on the board are both giving 23.8V while trying to warm up / under load. Bed warms up to the setpoint, hotend does not. The hotend heat probe increases some degrC (18 to 21 degrC) due to being close to the bed so that seems still to be working and ok.
Today I've flashed the firmware (it was already running v3.10) and still same result.
I've measured on the hotend-pins on the board directly and while requesting to warm up it remained on 0V. Contacting support via chat later this week.
You say that both power supply pairs are at 24v below the PSU, which is good.
Did you check the other ends at the Einsy? It should still be 24v at the Einsy terminals with the system trying to heat the hotend... with the system idle, you might get an ok reading which could change under load.
- Prusa MK2 upgraded to MK2.5
- Prusa MK3s
- Ultimaker 2+