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Bad Thermocouple Amplifier?

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Hello All,

I just finished assembling my Ultimaker last night and attempted to set up Cura today. I tried to run the "Checkup Wizard" but the program gets stuck on "waiting for head to cool down before temperature test" and won't proceed. This is when the head is at room temperature. The command processor shows that the thermocouple is reading 93.3 degrees. Just for fun, I ran pronterface and it showed the same thing... 93.3 degrees at room temperature. 93 degrees is also displayed by the Ultimaker controller.

I heated the head up using pronterface and verified it was hot using my finger (I'm not going to recommend that) but temperature display never changed from 93 degrees.

Here's what I have tired, and the results:

Unhooked thermocouple = 93

Jumper in place of thermocouple = 93

Reversed thermocouple = 93

Hot thermocouple = 93

Cold thermocouple = 93

Took off PCB, heated and re-flowed each solder joint with a soldering iron then plugged it back in = 93

Wiggle all thermocouple wires = 93 degrees solid.

Unplugged wire from motherboard = I don't remember exactly but i *think* it was around 180 degrees.

I also triple checked the wiring and thermocouple placement and it's as Ultimaker intended. Also,the LED does light up when powered on.

I left my multimeter at work so I can't yet follow Vinland's Guide http://www.vinland.com/blog/?p=138#more-138 (but will).

So what do you guys think? Bad amplifier chip?

Thanks in advance,


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Well, it is looking like a bad TC PCB. I'd forgotten that I had a thermocouple reader for my multimeter so I hooked it up and the TC worked perfectly. I reflowed all the solder joints on the PCB with my soldering iron and it still reads a constant 93 degrees. The LED lights up just find so I'm guessing the problem lies in the amplifier chip.

I'll be contacting UM Support about a replacement this week. Thanks for the help!

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First check if all cables are properly connected. And if the 3 wire connector is wired up correctly. There have been a few cases of the 3 wire connector being wired wrong, check if the colors (red/black/yellow) is in the same order on both sides. You could also swap it with the other color 3 wire connector.

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Had the same problem. Two wires were swaped the wrong way on the connector that goes to the tiny amp board on top of the print head. The wires that plug into the amp board with the white connector that has the black dot on it are the ones I am talking about. When you look at the white connector at the end of the wire with the black dot facing you and with it pluged in. The yellow wire should be on the left. The red wire in the middle and the black wire on the right. That fixed the problem with reading 93C all the time.


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Another problem I had was with the tempeture readings going up or down giving a temp ERR. This turned out to be a bad solder connection on the amp board. One of the leads on the green screw terminal connector was not soldered to the board good enough. I just had to touch up the solder joint and it works perfect now.


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Speaking of a TC-board?

Always having trouble where to place my questions on the forum :shock:...

Somebody knows why the boards are placed on the printhead, other than cosmetic blue led reasons.

To keep the printhead more compact I was thinking of moving them underneath the machine.

Any electronic/magnetic/Interference reason why I should not?


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