Manual Heat Bed...

I just finished wiring my setup up.  I verified my heatbed working without connecting my ramps.  It's a mains aluminum heat bed.  So I have an SSR for the mains and the other is the +/- for the bed from the controller.  My question is that when I manually turn on the heat bed it powers on (verified with the LED from the SSR) but then powers off 5 seconds after.  Thermistor shows the temp rise... then stops because it shut itself off.  Any help as to why it shuts itself off would be greately appreciated.


  • First check log for messages in case it is a decoupling test triggering. At least in repetier-firmware you will get a message why it disables the bed if that is the reason.

  • Ok, I'll do the logs and see what it says then report back.  Thanks!
  • The bottome log doesn't shot anything but the command that turns on the bed.  M140 s84*98... and that's it... Is there another log that i'm missing here?
  • Same for the hotend... I noticed the Dry Run button.  Do I have to do a dry run to test/verify the heating parts?

  • Dry run would prevent heating at all. It is for testing a print without filament/heating.

    Also what firmware are you using?
    Does the led for bed turn off?
    What does the temperature show graph for output show? Does firmware still think it is heating?

  • Fireware is what ever is the latest before the beta offered.  Yes, the let for the bed turns off.   It goes up an few degrees and that's it.  It obviously doesn't go any higher becuase it is turned off.  No, as far as I know, being new to this, it does not.
  • "Fireware is what ever is the latest before the beta offered. "
    that is no helpful answer. Is it repetier-firmware, marlin, ... is not answered and your problem is firmware related so this is the most importnant thing to know.
  • I'm sorry it's the Repetier firmware 92.9.  But I did figure it out.  PWM control doesn't like have SSR's to manage.  Read elsewhere that bang bang control is better suited for how I have my custom heatbed setup.  Thanks!  Love the firmware though!!
  • So SSR is too slow for the high frequence. Good to know.
  • Yes, that's what it seems like.
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