Temperature Issues

This is a problem that only recently developed, I've never had it before.

The reading on my temperature sensor is very inconsistent... it keeps fluctuation from 175~188ish very quickly. This is thereby causing the heater to act erratically.

Any idea whats going wrong here?

-Nick

Possibly a broken wire, loose connection or a faulty thermistor.

The wires to the print head can break inside due to constant bending backwards and forwards but the insulation holds the ends together so it makes and breaks with each move.

Does it do it when the head is stationary or only when it is moving?

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[www.hydraraptor.blogspot.com]

5V line issues causing reading problems with the ATMEGA? only noticed other day that my voltage regulator was hanging on had to get it out and solder a new 1

not got fans blowing near machine or anything ?

thermistor come loose and moving?

i would get the hot end out on the desk hook it up move some cables see if you get any funny readings

nophead Wrote:
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> Does it do it when the head is stationary or only
> when it is moving?


This problem just got a bit stranger... The inconstantcy is becoming more inconsistent. It doesn't happen all the time.

Fans: one small fan pointed at the machine running on low.

Thermistor loose: might be but I doubt it... It's secured pretty well.

-nick

>It doesn't happen all the time.

Yes, but does it happen when the machine is stationary or only when moving?

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[www.hydraraptor.blogspot.com]

nophead Wrote:
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> >It doesn't happen all the time.
>
> Yes, but does it happen when the machine is
> stationary or only when moving?

Usually when its moving but it stops after a while.

When its heating up (stationary) its a pretty smooth graph

-Nick

Then I would agree with not heads original suggestion, you have either a lose or broken wire, or a bad connection to either the thermistor or the heater.
The wires probably expand enough after the printers been running for a while to keep the connection, which is likely why is stabilizes.

You should check all the wiring to the Hotend., but if the break is in the wire, you likely won't see it.
You can start by wiggling wires when it's stable to see if you can force it to not read anything.

Measure the voltage across the thermistor as close to it as it is accessible in your wiring and look for drastic changes when it is intermittent. It will help you to know when and where the intermittent occur. Secondary, then measure the voltage as close to the microprocessor as is possible and it will help you isolate where the problem occurs.

Wow...

I finally found the problem.

I turned the machine around and looked where all the wires enter the hot end, and guess what was there.

An M8 hex-nut that fell of the extruder was lodged behind the hot end. It was connecting the heater to the temp sensor. I removed it and all is well.

-Nick

Hi, im building a mendel 3rd gen and i have troubles with the thermistor because this only indicates 1024 instead a temperature, im trying reset the board but it keeps the same, hope somebody can help me...the board is a extruder controller v2.2