The problem with the motherboard melzi.

remeslennik

Hi! Sorry for my English, it is a machine translation.
I melzi board, hot end turn on or off. In the program the temperature is 190 degrees, after the passage of this mark the end of a hot continuing warming. To avoid catastrophe, I turn off the power.  This is a problem particular board or can somehow affect the problem with the help of the firmware?

Repetier

190 should not be too hot. Many pla print with 210-215°C.

You have not said what temperature you wanted. Temperatures overswing at first set depending on your heat manager and parameters so 10°C more can happen but you should see reduced output when it happens..

remeslennik

Temperature for printing pla me want 190 degrees, hot end heats without stopping above $ 190 and I turn off the power at a temperature of 240 degrees, one in the line display temperature of the hot end of the figure was more than 400.
I decided that the problem of a particular board. I have it replaced. But another question arises is: to use it in the car without a warm table (bed) whether the firmware hang hot end of the bed to the contacts? And whether it will be operational after that?

Repetier

Leave hot bed contacts. Just do not enable the bed is enough to reduce power usage. The important part is to have the sensor. As soon as you remove sensor it will disable all heating as it detects a defect.

remeslennik

Do I understand that you have to offer on board thermistor disconnect the hot end, and in this case it should not be heated in any way, and if it is warm, then the problem is a fault in the board.

Repetier

Sentence is not clear,

Open host and go in temperature view and enable output view. Then you see when firmware tells it is heating. That means it has set some output pin to 1 which heats the extruder. If it does not happen it might be the wrong pin or a defect or wrong wiring. Some boards have separate 12V inputs for heaters. Use your multimeter to check if you get power or if an other output gets power.