temperature defect

MxB

temperature defect
May 14, 2018 05:38AM

Registered: 6 years ago
Posts: 6

Hello everyone.

I have issues with my PRotos V3 Printer by German RepRap.

The display shows "def" for both extruder temperatures and the bed temp. So I measured the resistance of the wiring of all temperature - sensors and the resistance appears to be ok.

Does anyone have any ideas what else could be the problem?

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o_lampe

Re: temperature defect
May 14, 2018 06:14AM

Registered: 8 years ago
Posts: 5,232

Did it work before?
If so, you might have a problem with analog ground on the controller. That's the only thing I can imagine, would "kill" all sensors at once.
Which controller is it?

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MxB

Re: temperature defect
May 14, 2018 07:09AM

Registered: 6 years ago
Posts: 6

It was working perfectly before. Had the same problem a few weeks ago but the wiring for the all temperature-sensors were broken. (Yes, ALL wires were broken, no kidding!)
Fixed the wiring issues back then and it worked. Now it's broken again.

The Controller is an Arduino MEGA 2560 and a Ramps v1.4.2 (http://www.germanreprap.com/myfactory/web/cms/produkt/100279.aspx).
Which pin number does the analog ground have?

Edited 5 time(s). Last edit at 05/15/2018 05:24AM by MxB.

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Trakyan

Re: temperature defect
May 14, 2018 07:15PM

Registered: 7 years ago
Posts: 507

Could the wiring have broken again? There's usually a reason if you end up breaking that many wires at once, did you fix the issue?

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MxB

Re: temperature defect
May 15, 2018 01:43AM

Registered: 6 years ago
Posts: 6

Ith wires are not broken. Already checked that. I guess it's a contoller issue

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MxB

Re: temperature defect
May 15, 2018 09:30AM

Registered: 6 years ago
Posts: 6

Re-measured the Thermistors and the cartridge heater of both Extruders and the bed (values in file attached)
Guess the bed is done... angry smiley

Any suggestions whether I should short circuit the bed or not? (Do I need a heated bed?)

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Attachments:
open | download - Unbenannt.PNG (7.3 KB)

o_lampe

Re: temperature defect
May 15, 2018 10:11AM

Registered: 8 years ago
Posts: 5,232

You can replace the bed thermistor with a 100k resistor. Shortcutting would lead to another error.
I have to replace thermistors frequently, that's why I have a few spare at hand. The legs of the bead brake off or the wires are only soldered, although should be crimped, too.
If you go shopping for replacement, better buy a bunch of 5-10...

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Dust

Re: temperature defect
May 15, 2018 11:44AM

Admin
Registered: 13 years ago
Posts: 7,001

I hope that image is in error?

re the bed
white wires going to D8? but that is normally the thermister, should be going to T2.
Red and black wires to T2? But that should be the heated bed on D8

1.2 ohms is about right for the heated bed...

To me It looks like you have tried to heat the bed by putting power threw the thermistor.. This will have killed the thermistor

Edited 1 time(s). Last edit at 05/15/2018 11:48AM by Dust.

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MxB

Re: temperature defect
May 18, 2018 02:00AM

Registered: 6 years ago
Posts: 6

Quote
Dust
I hope that image is in error?

re the bed
white wires going to D8? but that is normally the thermister, should be going to T2.
Red and black wires to T2? But that should be the heated bed on D8

1.2 ohms is about right for the heated bed...

To me It looks like you have tried to heat the bed by putting power threw the thermistor.. This will have killed the thermistor

The image is right winking smiley

But as I mentioned the printer was working fine and the bed was too. Guess it would not heat up, if wiring was wrong... hot smiley

But with the right resistance of the bed it seems like even the bed is still working...

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