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Lonestar
(@lonestar)
Active Member
Temperature jumping

I'm having an issue with the hotend temperature. If I set it to 235 it will get up to 235 then jump between 235 and 255 randomly and the print will not start. I changed the thermal resistor but that did not help. Any ideas? I'm running firmware 3.0.9

Posted : 16/12/2016 11:56 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: Temperature jumping

Rocco

Have a look here: http://help.prusa3d.com/mk2-electronics/thermal-runaway-and-temperature-drops?from_search=14217608

Particularly the section regarding the thermistor connector.

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Posted : 17/12/2016 10:00 am
Lonestar
(@lonestar)
Active Member
Topic starter answered:
Re: Temperature jumping

Thanks for the link. I had looked at that a while ago. I have two thermistors I'm testing. One that is hooked up regular like and the other soldered to the cable bypassing the connection. Same problem on both. Could it be a problem with my rambo board? Around the time I started having this problem I had a problem with the bed heater connection on the rambo. The plug got crispy and a bit burnt. It seemed like a hazard so I looked up the problem and saw that if the connection came loose it could fry the port and some recommended solder the bed heater directly to the board. I went ahead and did that since the crispy plug seemed like a bad idea. Could the damage to the board during that situation have caused problems with thermistor readings? Is there a way for me to use one of the other thermister ports to test if it is the port? The rambo mini has three thermistor ports and I'm only using two. Is there a way to make the system register port 2 instead of port 1 or whatever pin assignment it uses for the hotend thermistor?

Posted : 17/12/2016 12:13 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: Temperature jumping

Yes, you can amend Pins.h and recompile the firmware.

Pins.h from line 60:

#define TEMP_0_PIN 0
#define HEATER_1_PIN 7
#define TEMP_1_PIN 1
#define TEMP_2_PIN -1

Change TEMP_1_PIN value from 1 to 2 and plug the thermistor into the third thermistor socket.

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Posted : 17/12/2016 1:05 pm
Lonestar
(@lonestar)
Active Member
Topic starter answered:
Re: Temperature jumping

Awesome. I'll give it a try.

Posted : 17/12/2016 4:18 pm
Lonestar
(@lonestar)
Active Member
Topic starter answered:
Re: Temperature jumping

Well it looks like changing the pin worked. Guess there is damage on my Rambo or maybe some loose pins. I had to change
#define TEMP_0_PIN 0

to

#define TEMP_0_PIN 1

#define TEMP_1_PIN 1 didn't do anything. Took a while to figure out.

Posted : 17/12/2016 5:32 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: Temperature jumping

Rocco

Apologies, I got it wrong... Happens too often nowadays, sorry...

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Posted : 17/12/2016 6:13 pm
Lonestar
(@lonestar)
Active Member
Topic starter answered:
Re: Temperature jumping

No worries. You got me facing the right way. Just putting the info up there for future folk

Posted : 17/12/2016 6:14 pm
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