Bed Not heating

I was recently updating my prusa i3's firmware. After I updated I tried going through all the axes and heaters, and when I tried to turn on my bed it wouldn't heat up. My bed is running on 24v and is hooked up to a relay board. The relay board also has a led on it and I can see it flickering but very dimly, and every 3 seconds it lights up all the way but then it just goes back to flickering again. I think that this has somthing to do with the firmware settings. I am tring to update to Marlin 1.1.0-RC6 - 24 April 2016. Please help.

Check the power settings in marlin configuration h file, be sure is set for 255 and if PID is enabled that it is set correctly for your bed.

I have tried turning the PID bed setting on and off but with no success. I even tried the M303 command and put those numbers in my PID settings but it still doesn't work. But when I did do the M303 command my bed heated up just fine for the first few cycles of the test. What is going on here?

Edited 1 time(s). Last edit at 07/17/2016 06:50PM by kerfun.

Comment out the line that reads:

#define PIDTEMPBED

It should read:

//#define PIDTEMPBED

This enables Bang Bang control.

Also set

#define MAX_BED_POWER 255 // limits duty cycle to bed; 255=full current



These settings work well for me with a relay.

I have tried those settings, but it seems to not change anything. Could this be a bug with Marlin?

More likely a wiring error.

Have you checked the output voltage on the output terminals of the RAMPS board?

I figured it out. Apparently I had my fan pin and my heated bed pin on the same pin in my configuration file which is why it was acting the way it was. I feel very dumb now but thanks for all of your guys' help.