Heatedbed and hotend won't heat up

[Cale]

I've recently finished assembling my Rostock Max v2.I am now working with the Repetier software and having problems.When I manually turn on the heatedbed and hotend they won't heat up.The Repetier software also says the heatedbed temp sensor has a defect.Not sure if this matters,but when I turn on my printer the LCD screen shows this for the hotend and heatedbed temperatures.
NOZ: def Target: 0
BED: def Target: 0
I would appreciate any help you can give me.

Thanks,Cale

[Polygonhell]

The def implies you have a short or discontinuity in the thermistor wiring.

[Cale]

After several tests with an ohm meter I've figured out the heatedbed thermistor is broken or something.I am getting a new thermistor from SeeMeCNC.I'll post the results when it gets here.


Cale

[Cale]

I got the new thermistor,but immediately after installing it I had problems.For starters I know the thermistor is a good one. When I turned on the printer it showed DEF.After some tests I accidentally burned out the thermistor.I've now got another replacement thermistor.Before I install it I'd like to find out how to solve the problem from the first replacement thermistor.
I need help.

Cale

[Eaglezsoar]

I got the new thermistor,but immediately after installing it I had problems.For starters I know the thermistor is a good one. When I turned on the printer it showed DEF.After some tests I accidentally burned out the thermistor.I've now got another replacement thermistor.Before I install it I'd like to find out how to solve the problem from the first replacement thermistor.
I need help.

Cale

Not sure what you mean by a burned out thermistor. They rarely burn out, usually the wires on the thermistor breaks, a fuse on the Rambo opens, or a thermistor port on the Rambo gets blown.
We need some more details about what you mean by a burned out thermistor then we will be glad to help you figure out what is wrong.

[Polygonhell]

I agree with the previous poster, it's unlikely you burned out the thermistor. They can be physically damaged, but they are pretty robust electrically. The arduino reading the values is not, but you need to have accidentally applied the wrong voltage to the thermistor input to do any real damage there.
If it were me, I'd wire everything up first without mounting the thermistor to the Hotend, measure resistances with a multimeter to verify everything is good, then plug it into the thermistor port and verify the reported temperature is reasonable, then put the thermistor in the Hotend.