Problem temp A10M

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rellipas
Posts: 1
Joined: Fri Sep 28, 2018 3:49 am

Problem temp A10M

Post by rellipas » Sat Oct 06, 2018 9:55 pm

I have a problem with the temperature of the A10M are detected strange temperatures and if I disconnect the sensors the display instead of scoring 0 continues to give strange values ​​as I solve?

aarli
Posts: 37
Joined: Thu Sep 13, 2018 11:20 am
Location: Ireland

Re: Problem temp A10M

Post by aarli » Mon Oct 15, 2018 3:55 pm

Could you at least clarify which temperature are you referring to? The heated bed or hotend?
And what do you mean by strange temperatures? Can you elaborate? You only explained the temperature with disconnected sensor.

Was there a difference in temperatures between disconnected and connected sensor?

Thermistors used in these printers machines are typically 100Kohm at 25C Negative Temperature Coefficient (NTC) temperature sensitive resistors. Basic troubleshooting of a thermistor is to measure its resistance at room temperature, and compare it to the rated 100K resistance. If it is significantly smaller there may be some sort of short. If significantly larger, it make be an open circuit.

The values reported by the software are constrained to the values in the thermistor table, so an unusually large temperature that matches the highest temperature in the table indicates an open circuit, or unconnected thermistor. An unusually low value that matches the lowest temperature in the table indicates a shorted thermistor.

To me it all looks as if the temp sensor or it's connection failed (not shorted).

If you don't have a multimeter, there's one thing you can check: Unscrew the hotend assembly rollers and take it off. Look at the wires that go from the small circuit board into extruder. My A10M was poorly assembled and due to that some of the wires rubbed against the rail. Luckily I discovered that during some other thing I was working on. Otherwise I think I would've lost temperature sensor and/or shorted hotend heater power. The latter would've probably blown one of the fuses on the board, if not worse. This is difficult to see without temporarily removing the hotend assembly.

Luckily I discovered it in time, as one of the wires had already rubbed off its insulation. Fixed and installed the wires properly, so I shouldn't run into the same issue.
Geeetech A10 (with mods) + Geeetech A10M
Repetier Server on Raspberry PI 3, connected to printers for remote printing/firmware uploads.
Slic3r Prusa Edition, Simplify3D, Ultimaker Cura, Repetier host on the PC

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