Basic RUMBA start up question

Hi all -
I have a Mendel90 printer, and have swapped out my Sanguinololu (Sprinter firmware) with a Shiny new Rumba w/Marlin firmware, and have made all the updates to connections. I have a new 24V power supply as well, and motors and heated bed are working fine. My hot ends (he0, he1, he2) and fans (fan0, fan1) don't appear to be getting any voltage when I turn them on via Repetier. I checked the board, and each has a green status LED that comes on when I enable each, but not voltage. Did I miss setting something up in confguration.h in the Marlin firmware? It seems funny that both the hotends and the fans don't work - is this a 12v regulation thing? BTW, I am using v1, and can compile and upload firmware to Rumba no problem.

Any help on this puzzle would be much appreciated!
Thanks,
Rob

I have more clues on the puzzle...
Like I reported above, the green LED comes on for either the HE0 or FAN0 port when I enable them via Repetier. But unlike the heated bed LED, which is a solid green when enabled, these go bright green for a second, then out, then fade in to about half strength. Both LEDs have the same behavior.

Thanks,
Rob

Could it be that the PID_MAX setting in your Marlin configuration is wrong?

Anything's possible I suppose. Not sure why that would affect the fan though. I have included a handy-dandy graphic to show what's what.

I tried PID_MAX - no real change. By setting it to half (127 instead of max 255), I get the HE0 LED to flash with the duty cycle. Still no voltage. Just to show what I am seeing on Repetier...

Hi all -
I have been having a discussion with Geeetech about this board, and they are asserting that the RUMBA should only be powered up by a 12V supply. This seems counter to the spec, which states the RUMBA design can support 12-35V, with voltage regulation on-board. Does anyone have a RUMBA powered with a 24V supply? Any issues?
Thanks,
Rob

I had a Rumba powered at 28V and ran it for months, till I just upgraded to a Smoothieboard and haven't looked back.

I know now that I was having problems overheating the drivers. The symptom is shifted layers due to lost steps. These could be anything from a very minor shift to a big shift. If you use a higher voltage, and also high current then you have to have very good heat syncs and very powerful fan. Run-of-the-mill fans wouldn't do it. If you can keep your finger on the driver's heat syncs without getting burned then it's probably cool enough.

Double check the wiring diagram on the wiki here.

Note the jumpers just above the fan connectors. If you use a higher voltage, then make sure you position the jumpers properly or you will fry your fans.

Hope it goes well.

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My printer: Raptosaur - Large Format Delta - [www.paulwanamaker.wordpress.com]
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