Ugh.. Motherboard flashing green briefly then just red

Aagh. Someone please tell me I'm missing something simple..

The other day, and today, I was successfully moving a stepper motor forward and backward, using the RepRap host software.

I walked upstairs for one hour, came back down, and now nothing is working.

I have a new PC power supply connected to the motherboard (all 3rd gen electonics) currently via the big rectangular 24 pin connector (haven't removed that yet). I have power going via a molex connector from the power supply to a stepper motor controller. The stepper motor controller is connected to the motherboard via a 6way ribbon cable, and to an optoendstop board via 3way ribbon. An extruder controller is connected for the hell of it via cat5 for now.

The computer is connected via the USB assembly I completed, which connects to the motherboard (yes, it's orientation is right on the ribbon cable).

FiveD firmware on the motherboard and extruder controller.

All of this worked before. Before, when the power supply was off, everything was off. Turn it on, and the motherboard flashed red. Turn the motherboard power switch on, and all of the boards light up green.

Not any more. Now I get the flashing red, and when I turn the motherboard power switch on, I get a super brief green flash on all boards then back to red.

If I disconnect everything and only have the motherboard connected, same thing. Brief green flash, power supply fan fails to come on, etc.

Ideas?

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--Jeff Keegan (Just Another RepRap blog)

Keeping notes here in case anyone else runs into this problem, or if this helps anyone figure out what my problem actually is.

So, at the very least it turns out the board isn't completely dead. The PC can communicate with it. When I run the RepRap host and everything is disconnected, I get nothing, but when I run with the motherboard connected (and powered), I get responses (at least protocol wise):

$ ./reprap
Experimental: JNI_OnLoad called.
Stable Library
=========================================
Native lib Version = RXTX-2.1-7
Java lib Version = RXTX-2.1-7
RXTX Warning: Removing stale lock file. /var/lock/LCK..ttyUSB0
Java 3D WARNING : reported GLX version = 1.2
GLX version 1.3 or higher is required
The reported version number may be incorrect. There is a known
ATI driver bug in glXQueryVersion that incorrectly reports the GLX
version as 1.2 when it really is 1.3, so Java 3D will attempt to
run anyway.
comms: G-code: T0 dequeued and sent [0.000s/-1272307865803ms]
comms: GCode acknowledged [0.000s/0ms]
comms: G-code: M105 dequeued and sent [0.004s/4ms]
comms: GCode acknowledged [0.004s/0ms]
comms: G-code: G1 F1500.0 dequeued and sent [14.730s/14726ms]
comms: GCode acknowledged [14.731s/1ms]
comms: G-code: G1 X0.1 F1539.5 dequeued and sent [14.733s/2ms]
comms: GCodeWriter.waitForOK() - temperature reading: T:0 [14.733s/0ms]
comms: GCode acknowledged with message: ok EB [14.733s/0ms]
comms: G-code: T0 dequeued and sent [14.752s/19ms]
comms: GCode acknowledged [14.752s/0ms]
comms: G-code: T0 dequeued and sent [16.253s/1501ms]
comms: GCode acknowledged [16.253s/0ms]
comms: G-code: M105 dequeued and sent [16.254s/1ms]
comms: GCode acknowledged [16.254s/0ms]

Testing continues..

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--Jeff Keegan (Just Another RepRap blog)

Solved!

It was the power supply.

I tried jumping the green and black wires without ANYTHING connected, just to hear the power supply's fan. Nothing.

Then I found an old PC lying around in the basement that I haven't used since we moved. I brought it over, unplugged its power supply from its motherboard, jumped ITS green and black wires, and powered it on. THAT power supply's fan came on.

So then I removed the jumper, plugged that power supply into my RepRap motherboard, and tried again.

Success! I was able to move the motor again via the RepRap host.

I'm so glad that the piece blocking me was an easily obtainable power supply, instead of a backordered, difficult to obtain motherboard (which I'd treated gingerly!).

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--Jeff Keegan (Just Another RepRap blog)

Almost the same happened to us, the power supply wouldnt turn on before we jumped those cables.