Thermistor 100k HW readings

Hi there,

I have an working Prusa i2 for 8 months or so,temperature reading was 25C when printer started and prints were fine.
Anyway i fried my thermistor and got a new one 100k HW ,it is proprely insulated with teflon and kapton tape but when idel it reads around 65C which is wrong.
In sprinter i've put option #7,but again it reads 65C ,any help would be much appreciated


All the best

Luka

No ideas?

1. have you checked you have the right thermistor selected in your firmware after the update ?

2. the other approach would be to check your thermistor is reading correctly. take off ramps and just test the thermistor directly on the arduino (assuming you have an arduino type setup).


http://playground.arduino.cc/ComponentLib/Thermistor2#.UzVQJah_vz4

there are other examples available of reading a thermistor on arduino, just do a search

I got weird readings on both my thermistors when I selected the ones I had in the firmware hotend 65 heat bed 88.

My solution where as simple as slecting and testing each one in the firmware until it read room temperature and then hold a finger and looked if the reading changed.
And then the same on my heatbed and placed my hand where the thermistor is.

Now do I have 22 hotend and 21 heatbed that is the same as the room temperature.

And so far does everything work as they should but iam still in early stages.

And there should also be noted that the heat is not on when I do this

I belive there is some difference from the suppliers even if they should be the same?

Edited 1 time(s). Last edit at 03/28/2014 12:44PM by Cliff Mellangård.

Hi all,

Just to give an update on thermistor reading 65C instead of 25C room temp,my pins on RAMPS 1.4 were burned therefore the wrong reading.Switched the pins and its all working fine.

What pins were burnt?

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_______________________________________
Waitaki 3D Printer

Extruder thermistor was on T0,and bed thermistor on T2...T0 and T1 are burned only T2 is left working
Any ideas if I can get RAMPS 1.4 from Ebay or someware else?

If you live in Sweden so are I waiting for 2 sets of ramps 1.4 with 10 step sticks in the mail.
I will sell them for wath I my self payed for them.
We reprapers must stick together
So I belive the price for a ramps board is not that high it self as I bought a kit and I want the step sticks more.

I can actually recommend a Chinese guy on ebay that shipps really fast to me at least 1-2 weeks.

[www.ebay.co.uk]

I started to order most of my stuff from this guy as I often got 3-5 weeks delivery on many other Chinese sellers.

The soldering don't look that 100 % but they work as you can see here on my printer

[www.youtube.com]

Thx for the link i will order one today

Rather than paying for a new RAMPS board why not just remove the old pins and solder in new ones, cost would be about 30p GBP