Heatbed not heating up!

Hello forum,
I have have just finished assembling my Drubie Prusa Mendel i2. (Durbie is just another Prusa mendel but with some modifications made by romscraj, romscraj.com). It' working perfectly fine except for one thing, the heatbed that came with my kit isn't heating up. I followed the instructions and everything but it doesn't heat.

The problem isn't the thermistor, since it does read the room temperature (it does it rarely when I click "check temperature" on pronterface, but it does seem to work). So can you see if my soldering and wiring are alright.

also, I sent a email to the guys that made the kit, romscraj, and told me:
"Try adjusting the pins of the heater thermistor wire. They might be loose."

I think they're all right.

Quote: (it does it rarely when I click "check temperature" on pronterface, but it does seem to work). End quote.

What does that mean, "rarely"? -it either works constantly or it doesn't. If its intermittent then there is your problem.


Anyway, if its ok then...

The first thing to do is switch on the heatbed. Then, using a meter, put the meter probes on the heat bed connections (both sides) and check that you have 12v there. If not, go to the green plug on the driver board and see if there's 12v there.
If there is 12v at the heated bed terminals, then check the continuity of the PCB itself.

rarely means it doesn't do it often. Maybe I'm not turning it on correctly or it has a short.