Burned connector on main board

[dpelaez 1]

Hello everyone,

I have an Ultimaker 2 that I purchased around 4 years ago that stopped heating the build plate. I verified that the build plate was heating by manually powering the plate with a power supply. I removed the plate to access the board and found that the conector where the build plate is connected was completely burned as you can see from the image. Does anyone know why this could have happened? 

Edited July 13, 2018 by dpelaez

[gr5 2,270]

That's caused by a loose wire.  power, measured in watts is I*I*R where R is the resistance and I is the current.  Normally the resistance of the heater is about 4 ohms (roughly) and the voltage is 24V and so the current through the heater is about 6 amps.

 

In the wire to the heater the resistance is probably less than 0.1 ohm but even if it was that high you would get 36*.1 or 3.6 watts distributed through the whole wire.  Not a big deal.  But if you get even 1 ohm of resistance at that connector that's 36 watts going into that tiny spot and it gets quite hot.

 

Even though it looks like crap it probably still works fine.  Ideally you want to remove all corosion off of all metal parts that touch the wire.  So if you have a tiny file you could slide it in and out of the hole where the wiring goes in to clean it out a bit and reinsert the wires.  This time clamp it down TIGHT.

 

[Dim3nsioneer 558]

You should not operate the board in such a condition. It's a high risk for a fire as further short cuts are likely due to the decreased resistance of the plastic (burned plastic gets conductive).

At least you should replace the connector with a new one if the pcb itself is undamaged.

[dpelaez 1]

I had a few terminal blocks laying around that have the same pitch as the one soldered on the board and I replaced the terminal block. Printer is back up and working.

Thanks for your replies.

 

[gr5 2,270]

nice