# Taz 5 not maintaining hot end temperature

**URL:** <https://forum.lulzbot.com/t/taz-5-not-maintaining-hot-end-temperature/2018>\
**Category:** LulzBot TAZ\
**Created:** [July 19, 2015, 11:36pm UTC](https://forum.lulzbot.com/t/taz-5-not-maintaining-hot-end-temperature/2018 "2015-07-19T23:36:34Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Farris](https://avatars.discourse-cdn.com/v4/letter/f/3ec8ea/32.png) [@Farris](https://forum.lulzbot.com/u/Farris)\
**Post date:** [July 19, 2015, 11:36pm UTC](https://forum.lulzbot.com/t/taz-5-not-maintaining-hot-end-temperature/2018/1 "2015-07-19T23:36:34Z")

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I’ve had an issue with my Taz 5 over the past week where it has not maintained a steady print temperature. This seems to be an issue no matter the model that I’m printing or the material (tried ABS and PLA). The temperature is swinging wildly (20 degrees in either direction) within a couple seconds. Do I just need a new thermistor maybe?

I’ve attached a screenshot of the last 30 minutes of temperature readings from my last print attempt.

 ![temperature.png](https://us1.discourse-cdn.com/flex020/uploads/lulzbot/original/2X/c/c50290e5c059b1febea003676d2ea6c1a34aecfa.png)  
Any help/insight would be greatly appreciated.

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**Author:** ![piercet](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.lulzbot.com/piercet/32/12_2.png) [@piercet](https://forum.lulzbot.com/u/piercet)\
**Post date:** [July 19, 2015, 11:44pm UTC](https://forum.lulzbot.com/t/taz-5-not-maintaining-hot-end-temperature/2018/2 "2015-07-19T23:44:05Z")

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Thats probably electrical unless you have a really strong fan / air conditioning on the hotend. Likely thermistor or heater core.

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**Author:** ![Farris](https://avatars.discourse-cdn.com/v4/letter/f/3ec8ea/32.png) [@Farris](https://forum.lulzbot.com/u/Farris)\
**Post date:** [July 19, 2015, 11:48pm UTC](https://forum.lulzbot.com/t/taz-5-not-maintaining-hot-end-temperature/2018/3 "2015-07-19T23:48:59Z")

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Thanks. My guess is thermistor because I don’t think that there’s any way it could cool off 20+ degrees in less than a second. Bad readings. I’ll look at soldering on a new one.

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**Author:** ![Farris](https://avatars.discourse-cdn.com/v4/letter/f/3ec8ea/32.png) [@Farris](https://forum.lulzbot.com/u/Farris)\
**Post date:** [July 24, 2015, 7:10pm UTC](https://forum.lulzbot.com/t/taz-5-not-maintaining-hot-end-temperature/2018/4 "2015-07-24T19:10:24Z")

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Just finished replacing the thermistor and, so far, the temperature remains constant.

Just in case anyone was wondering, it’s a Semitec 104GT-2. It is not the 100K Epcos that’s on the website, which won’t even fit. I only say this because I called LB support and they said to use the Epcos.

I ordered my Semitec through Mouser and their standard shipping was pretty quick. I’d use them again.