Err. MAXTEMP 100/0 degrees

[dampmaskin 0]

Hi. I have assembled my first 3D printer, the UM Original PLUS.

I almost got it working right, but then it started reading erratic temperatures from the print head. Then the board seems to have gotten stuck on the MAXTEMP error. Disconnecting everything did not help.

It shows 100/0 degrees for the nozzle, regardless of whether I have the sensor plugged into the board or not. I have even tried unplugging everything except the Ulitcontroller, no difference. Then I tried plugging in the USB and disconnecting the Ulticontroller, still no difference.

I suspect this is a firmware issue, at least I hope it's not hardware. It does not seem to be a problem with the sensor, because the error message is exactly the same whether the sensor is connected to the board or not.

I have read something about a firmware bug in the UM2 triggering the MAXTEMP error, and as far as I understand the UMO+ uses the same board, so maybe this is related?

Perhaps I can install an older version of the firmware, or make some modification to the existing firmware (MarlinUltimaker-UMOP-250000.hex)? If anyone could point me in the right direction, I'd be thankful.

Update: I just measured the resistance of the thermocouple, and it's open (infinite). I guess that's what 100 degrees mean, then. So it's not a firmware issue after all. Oh well. I guess I'll have to get a new thermocouple, unless it is fixable.

I'll have a closer look on it. Hopefully the break is somewhere that can be soldered. Is the normal resistance 100 Ohm at 20 degrees?

 

[dampmaskin 0]

Yee haw! I am 3D printing!

I'm probably going to have to replace the thermocouple sooner or later, but right now, magic is happening on my desktop.

 

[illuminarti 17]

Congratulations, and welcome to the club!

Resistance is 100 Ohms at 0ºC. It should be around 108 Ohms at room temp.

How did you fix the problem?

 

[dampmaskin 0]

I did not fix it per se. I removed the thermocouple, and measured 111 Ohms. Then I put it back in, and measured 550 kOhms. Took it out, 111 Ohms. Turned it upside down, and put it in, and then it worked, sort of.

I get maxtemp errors during preheat and cooldown, but as long as I am able to successfully preheat the nozzle, I am able to run prints. I will probably need a new thermocouple, though. I don't want to take this one apart unless it fails completely.

 

[gr5 1,305]

Open a ticket with support.ultimaker.com. Refer to this thread and they'll send you a new one. The part (if you want to fix it yourself) is a PT100 but don't use regular solder which melts around 250C. You need to do mechanical connection only (or use 300C lead solder).

I recommend doing the ticket now as it may take a few weeks before they get around to your ticket.

 

[yellowshark 149]

Alternatively if you do not have lead solder I think you will find that silver solder melts at a much higher temp. Available at online jewellery bits stores

 

[dampmaskin 0]

Thanks for the tips. I have a ticket open already. I know a jeweller's shop where I can get some silver solder if I need it. For now, I live with it.

I have an unrelated problem, and I wonder if I should open a separate ticket for that, or if it's better to keep it in the same ticket?

Here's the thing: The screws for the heated bed are sticking up, lifting the glass plate away from the heat plate, and probably also warping it ever so slightly. I have to run the bed at 80 degrees for PLA to stick, which is insanely hot for PLA as far as I understand.

I doubt that I can get anything bigger than 10 x 10 cm to stick, the way things are now. There's always a corner lifting, but if I try to reduce the distance to the nozzle by just a tiny amount, I obstruct it. The PLA just refuses to stick to the glass, especially if I run at anything less than 70-75 degrees.