Rostock Max V2 not heating up What to check?

[mozul]

The nozzle on my Rostock Max V2 is not heating up all the way anymore.
If I set the temp directly on the printer to 200C, it can only get to around 162C after about 20 minutes. It used to be quite quick getting to temperature. What should I check? This is the original machine with upgraded 12V power supply otherwise it is original.

[geneb]

Is the heating that slow with the bed not heating at all? If so, one of the heating resistors in the hot end may need to be replaced.

g.

[mozul]

Yes, I am just using the control panel on the printer and only heating the nozzle. It is slow and I am not heating the bed. I will disassemble the hot end and check the resistors.

[mozul]

I cut the wires to the power supply, and the resistance through both resistors is 80 ohms now . I ordered new resistors.

[geneb]

Yep, they ded.

g.

[Outsider]

I had this happen to mine a while back. (also a ver.2)
Th first time it happened, it was a hot end resistor. I changed to a E3D ver.6 and the problem stopped.
The second time it happened was traced back to the power supply. I changed that and have been problem free since.