Geeetech

I was in the middle of a 5 hour print when the heat bed stopped heating. The temp still read but it wont heat up. I tried to warm up the heat bed after the print and it just stayed at the same temp and did not heat up. I checked the wires connected to the mainboard and they are fine. Any ideas?
Thanks

Does the LED lignt under the hotbed socket lighted up when heating?
And unplug the hotbed wire, measure the resistance of the hotbed, it should be 1-2ohms. less than 1ohms is shorted and infinite is open circuit.
Or could it be the problem of the thermister? how about swap it with the extruder one?

The LED light does not come on anymore. Switching it with the extruder thermister did not help. Kind of bummer since it was only my third print.

"The LED light does not come on anymore."
LED lights does not come on, so I think the mosfet of your hotbed that controls the heating it dead.You can check the mosfet as follows: use the multimeter to measure the voltage between pin 2 and pin 3 of the mosfet, when heated up it is 0V,and when not it is 12V. If not , then it is dead. the mosfet type is as follows, you can buy one in your nearby electronic store and replace it.
name specific type
mosfet TO-220 STP55NF06LTO 　

I have the same problem but I am having difficulty sourcing a replacement mosfet.

The ones I can find (UK based) are mosfet TO-220 STP55NF06L (sold by RS, Farnell etc.)

The one stated above is mosfet TO-220 STP55NF06LTO (note TO at the end).

Apologies for my naivety, I know some fundamentals of electronics and can work my way around a soldering iron and a circuit diagram but I'm out of my depth here a bit, any help would be most gratefully received.

Neil

sambam1973 wrote:I have the same problem but I am having difficulty sourcing a replacement mosfet.

The ones I can find (UK based) are mosfet TO-220 STP55NF06L (sold by RS, Farnell etc.)

The one stated above is mosfet TO-220 STP55NF06LTO (note TO at the end).

Apologies for my naivety, I know some fundamentals of electronics and can work my way around a soldering iron and a circuit diagram but I'm out of my depth here a bit, any help would be most gratefully received.

Neil

Hi,
Where did you buy the printer,i think you can contact the seller for the mosfet replacement...

I bought it through Ebay. A quick look at the seller and it is unlikely they will supply them, ultimately they are a printer stockist by the looks of it.

sambam1973 wrote:I bought it through Ebay. A quick look at the seller and it is unlikely they will supply them, ultimately they are a printer stockist by the looks of it.

So,why not try buying the mosfet you posted before?

That was the question I was asking sorry. Will that one be OK? I am not fully versed in electronics and didn't want to damage the board.

Too much worry.It is not so easy to damage the mothereboard by the mosfet...Also,you can ask the seller if the mosfet is compatible with the board,i believe the seller will help you about it