Gen6/Sprinter/pronterface hotend issues

I'm a noob to this and trying to get my first printer going. The issue I'm having is the hotend doesn't seem to be heating up. I'm using a 6.8 ohm power resistor. I've checked the resistance and I measured 7 ohms across the power resistor and about 92k ohms across the thermistor. I have a Gen6 board with sprinter loaded using pronterface. Pronterface gives back temp readings of 20-30*. I'm using a 12v 5A supply.

I've tried to load Marlin and I can't seem to get it to verify. Using Arduino 23 there are many errors. Everything else with the printer works fine. All axis work fine as well as the endstops. Not sure what I'm doing wrong or what to check for issues.

thanks
jeff

I think 5 Amps won't be enough. You are probably current-limited. Try with a larger power supply, like say 18-24 Amps.

PC power supplies are commonly used for this purpose.

[reprap.org]

5A has been enough for me. As long as you don't try running a heated bed. Try measuring voltages on the connector for the hot-end.

Try putting a voltmeter across the heater leads after turning it on via Pronterface, and see if it reads 12V. If not, it's a firmware problem.

I turned on pronterface, hit set heater button then measured the voltage across the heater leads and it's 0v. I removed the power resistor and I measured 12.6v. I'm not exactly sure what this means.

thanks

Your power supply is bad since you're established that your hot end resistor is not shorted.

I tried just connecting the resistor straight to the 12v power supply I have and it got hot in 15 sec. So I don't think its my power supply. Could it be the mosfet on the board is bad or some setting in the firmware I'm missing?

So I think its solved. I dug into the config file and ended up commenting out the heated bed thermistor. Figured if there is no heated bed maybe pronterface might not power up if it can't find thermistor. It heated right up. So now onto my first prints.

thanks