Rumba plus board hotbed not heating

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mmrvelj
Posts: 4
Joined: Sat Jun 23, 2018 9:19 am

Rumba plus board hotbed not heating

Post by mmrvelj » Sat Jun 23, 2018 9:47 am

I have a Rumba plus board, that I bought as an upgrade to my Anet A8. I managed to get the board functional for most of the things (steppers in all axis, LCD with buttons, thermistors, endstops, fans ..), however I cannot get the hotbed heating to work. When I set HB temperature the bed is not heating.
  • 12V power is connected to both main power (MAIN-PWD) and hotbed power (HB-PWR) (reference picture below)
  • When I turn on HB heating (e.g. set temperature above ambient), I can see that the LED (LD2) turns on, but no voltage can be measured on the terminal (HB-OUT) for hotbed
  • If I connect the hotbed cable directly to 12V of the PSU the hotbed heats
  • Voltage cannot be measured with the Hotbed connected or disconnected to HB power terminal on Rumba
  • I borrowed identical board for testing and same problem occurs on second board
My heater definition in pins_RUMBA.h is defined as it is by default:

Code: Select all

#define HEATER_BED_PIN      9
Since I tested with second board, I doubt it is issue with the Rumba board, and I think that I am overlooking something? What could possibly be problem?

Board:
Image

mmrvelj
Posts: 4
Joined: Sat Jun 23, 2018 9:19 am

Re: Rumba plus board hotbed not heating

Post by mmrvelj » Sun Jun 24, 2018 11:19 am

I did a workaround by redefining hotbed pin to use Heater 1, and hooking heater 1 to a MOSFET control board. This works without problems, but my OCD is not accepting this (yet) as a permanent solution.

Does anybody knows - how good is the on-board MOSFET compared to external one? I read here that they improved it, but still - perhaps having external MOSFET is even better approach?

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warren.watts
Posts: 23
Joined: Wed May 02, 2018 7:18 am

Re: Rumba plus board hotbed not heating

Post by warren.watts » Fri Jun 29, 2018 8:06 am

I know this sounds basic, but have you checked fuse F1 (the 20A fuse directly behind the heatbed connector)
Image

mmrvelj
Posts: 4
Joined: Sat Jun 23, 2018 9:19 am

Re: Rumba plus board hotbed not heating

Post by mmrvelj » Sun Jul 15, 2018 8:24 am

Yes I did check. Fuse is OK.

My workaround with MOSFET works just fine. I even think it might be safer approach, specially since Rumba board seems to behave strange sometimes. For example from time to time when I turn it on it get's stuck and wont work. If I leave it for few hours its and turn it on again it just works. Very unreliable.

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