PSU cuts power when Heatbed Thermistor is attached

Hello everybody.
As described in the title, my PSU shuts down immediately after turning it on.
Before, it had worked for months in this configuration. I bought it new around half a year ago so didn't expect a failure.
Turning it on without the motherboard attached works fine: the fan runs, the mosfets show their power led and I can measure the 12V with my multimeter.
But as soon as I turn the PSU on with the fully connected board, it cuts power.
So, I tried only the motherboard and screen and voila - it's working.
Next, I tried with thermistors attached (as otherwise I can't print). Hotend thermistor? No problem! But when powering on with Heatbed thermistor attached to the mainboard, PSU cuts power.

Any clue why this might happen??
I have soldered the heatbed-thermistor wires directly to the heatbed. So it can't be a bad connector or something.
Please help!!

Thank you in advance for any help!!
Dave

I would disconnect the heatbed thermistor connector that plugs into the mainboard then plug another thermistor into the mainboard (just hanging in the "breeze" above the motherboard) and see what you get -
a 100k resistor would probably do if you are short of a thermo.
If the power supply stays on, you will know what to do next!

---

_______________________________________
Waitaki 3D Printer

Quote
waitaki
I would disconnect the heatbed thermistor connector that plugs into the mainboard then plug another thermistor into the mainboard (just hanging in the "breeze" above the motherboard) and see what you get -
a 100k resistor would probably do if you are short of a thermo.
If the power supply stays on, you will know what to do next!

Thank you very much! I do have a few 100k hotend thermistors lying around, will definitely try that!
Great idea

Edited 1 time(s). Last edit at 08/20/2017 09:55PM by printer_dave.