Everything seemed to assemble ok and everything else works except that Repetier isn’t showing the bed temperature and manually turning the heater bed on doesn’t heat the bed up. I can’t see anything in the options for Repetier or Slicer that could enable or disable the presence of the bed. It seems to connect ok with no errors.
I just have the basic k8200 with no extras so my understanding is the firmware version should be fine. I measured the thermistor and it was 674k at room temperature which is higher than the 100k I believe it should be. It does change value if I heat the bed manually with a hairdryer. I also tried unplugging the thermistor connection from the controller board and replacing it with a normal 100k resistor, but Repetier still doesn’t register that there is a heated bed present.
I’m starting to think the board might be faulty. Any advice on steps to take now?
0C indicates that there is an open for the bed thermistor.
Unplug therm2 and check for resistance on the cable (not the board)
at room temp you should see around 100K ohms
Yup, I disconnected the thermistor cable from the board and measured the resistance from the cable ends. I got 674k. I have also connected an actual 100k resistor to the connector on the board and it still says 0 degrees with no bed temperature showing in the bottom of the window. It’s like it doesn’t think it has a heated bed at all.
Even if the thermistor was faulty, I’d have thought the board should heat up when I turn it on manually in Repetier, which it doesn’t.
The bed heats up if I connect it to my programmable power supply.
Also, I understand the board is basically an ATMega2560 at its core. I have been programming Arduinos for a few years, so I understand I should be able to flash my own code to it and see if the chip itself is getting readings from that ADC and then flash your code back in afterwards?
If so they I can do some more diagnostics for you from this end. Please let me know if this is ok.
What version of Repetier do you have.
You can download the one that is configured for the K8200 from this link. http://www.k8200.eu/downloads/files/downloads/setup_repetierhost_k8200_0_95f.zip
This is a good starting point.
674K ohms is to high for the thermistor.
This would make me think that the thermistor was damaged when you soldered in on the bed.
Try measuring across the thermistor to see if you can track the problem down.
I accept that the thermistor may be damaged, but that’s not the problem. If that was all, then Repetier would display a temperature, albeit wrong, and would allow me to control the heated bed. It does not.
I appreciate the help you’re giving, but I have already answered this. Can you please have a good read of my other replies where I have noted this detail and also other steps I have taken to diagnose the problem.
That’s what I figured too. I’m happy to accept I may have damaged the thermistor. I’m not used to dealing with SMD and it’s a bit fiddly. I don’t see how I could have damaged the board though, I’m used to dealing with Arduinos and the like and used the same precautions with it.
Should I go back to where I bought it for warranty replacement?
A suggestion I had from another forum was that I might have the wrong firmware loaded. The instructions said to check for updates so I did and applied the one in a file called firmware_k8200_v2.1.1.zip.
Could this be the problem? Can you link to the firmware I should be running?
This depends if you have the K8204 on your machine.
All downloads for the K8200 can be found in this link. http://www.k8200.eu/support/downloads/
You will need to match the description with what you have on your machine.
All versions have the heated bed on them.
When loading the firmware use Arduino software 1.0.6 or lower.
If you used something higher that very well could be the problem.
Ok, I downgraded my Arduino software to 1.0.6 and uploaded the v1 firmware. I can see in the bootup that this is the loaded version but it still doesn’t work. I do not have the 8204 kit.
I see when I manually turn on the extruder heater or the fan that an indicator light lights up on the controller board. This doesn’t happen for the heated bed.
FWIW I really like the printer. I’ve managed to get quite a few successful prints by manually controlling the bed from my programmable power supply. Will be perfect when I get this bit sorted out.
