Hotend Stuck at 357 Degrees

My Hotend is reading at 357 degrees for some reason and wont change.

I have made sure that the thermistor is connected to the right slot, and I've even resoldered the wires to make absolutely sure. I've also checked with sprinter firmware and found out that the Marlin firmware is not actually the problem. Sprinter is also reading my hotend at 357 degrees despite it being cold as ice.

I checked online and someone had the same problem but they had accidentally reversed the thermistor connection with the hotend connection. I have double and triple checked this and this is not the issue. Ive even resoldered the wire. Any ideas?

Is it possible that my thermistor is shot?

Your thermister may be shorted, check it's resistance.

Quote
stephenrc
Your thermister may be shorted, check it's resistance.

how do i do that?

and woul;dnt a short be solved when i resoldered? one of em would have worked, no?

A thermistor is a resistor. At room temperature it should have about 100K Ohm. If it hasn't it's shot.

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With a multimeter at the connector that you would plug into the controller. It should be around 100K ohms, the exact amount depends on the room temperature. Most of the time it'll be less than 100K. If it does measure ok, then check to make sure you have the correct thermister selected in the firmware. If that's correct, then there is a problem with the electronics.

I dont actually own a multip meter

I did, however, switch the bed and hotend thermostor connections.

The bed Thermistor (which is attached to the bed but connected in the thermistor slot) reads about 22 degrees and will NOT change despite setting a high temp. The hotend thermistor (which is attached to the hotend but connected in the bed slot) still reads 357 degrees

Any idea what this means?

Edited 2 time(s). Last edit at 01/18/2014 05:16PM by kfootball15.

If you are going to fiddle with electronics such as a self-built 3D-printer, you kind of 'need' a multimeter. It's really easy and it's a breeze when you finally know for a fact what's up with your electronics. Instead of guessing