Heatbed Causing Disconnect When Turned On

Hey Everyone

Was hoping to get some feedback on an issue i am having

Recently put together a RepRap and did a few decent prints.
out of nowhere I had an issue with the MOSFET that caused it to turn on every time i gave power to the 11A power rail.
I have since replaced the MOSFET with a new one (IRLB8743) and it functions as expected with 1 minor flaw.

Every time I give power to D8 while the heatbed is connected I get a disconnect message from pronterface.
The weird thing is, when i unplug the heatbed from D8 and set the bed temp the light on the ramps board goes on and it does not disconnect.

I am thinking there is some kind of short on the heatbed, but i have thoroughly inspected it and there doesnt seem to be anything that looks suspect.
I am using an MK2a Heatbed and have not had issues with it in the past - only since i replaced the MOSFET.

any help would be much appreciated.

Regards,

Steve

Edited 1 time(s). Last edit at 03/20/2014 08:24PM by equinox86.

How many ohms does your heatbed measure?

Check the 4 corner mounting holes are not shorting to the frame - these holes are plated and some boards have been found to have a direct track to the heating array.

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Waitaki 3D Printer

Hey

Thank you both for the feedback.

I wad an able to limit the issue to the power supply.

I have a 350W bench supply in the other room ans hooked it up with my raspberry pi. I was able to heat the bed up no problem with that setup.

Very strange though. On the other power supply I could not get it to work in windows or when I booted the computer in OSX. Both pronterfaces threw me the error as soon as I turned on the bed power, however the bench supply and pi combination was able to turn om and print for 2 hours error free.

Thanks again