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I have a stock rostock that I think the RAMBO has failed on. At the board outputs I have no power out for fans, PEEK fan, or hot end. The power to the bed works and both thermistors work and read. What seemed to kick all this off was the PEEK fan itself overheating and it looks like it shorted. The print stopped and the display read "Killed" All the power supply leads show 12VDC across all leads. I checked for voltage at the RAMBO not any of the wire leads. so I know it isn't harness.
Any ideas, suggestions, $.02 are appreciated.

check fuses... particularly F3 in the pic below... if the fan shorted, and from what you are describing, F3 would be the one that is popped..

[img]http://reprap.org/mediawiki/images/b/b4 ... -fuses.jpg[/img]

links to buy replacements are on the rambo wiki here... http://reprap.org/wiki/Rambo#Fuses

Guanu

That was blown, much thanks. I have ordered replacement plus spare fuses to have on hand.

Upon replacing the fuse… The extruder fan does not turn off. The LED lights on that output and it does not respond to the Gcode that would turn it off and on. The extruder heat and other cooling fans now work as previous though, so that's something.

if you are talking about the fan that blows on the peek section of the hotend, it should always be on, no matter what material you are printing...

Guanu

It should always be on, however, you had the ability to control the voltage by placing a value up to 255 in the gcode. It also meant that once the print was done at 2AM that the fans didn't sit running all night long. So something is a bit off that I need to address. It seems unfortunate to buy a new Rambo to get this functionality back since they seem to be out of stock virtually everywhere.

if the printer is at room temp and you turn it on, does it automatically turn on? in the firmware its set to turn on when you turn on the hotend, and it will remain on after the print until the temp drops below 40c, and shut itself off... theres no variable setting on it anymore as it should be on 100% at all times the hotend is warm, so in the firmware it just turns that pin to ON rather than pwm...

Guanu

Yes, it just comes on when the printer is turned on now. I've been searching the firmware to see what I should adjust. Do you know what setting to change it back to pwm or to only have it come on when the hot end is on?

if it comes on everytime you have power to the machine, check the negative wire to that fan, it must be shorted out somewhere, the fans are negative switched, and that could be why your fuse blew... they will have a constant power, and the negative is switched, so its grounding out to something..

It does not look like it's grounding out to anything. No short in the harness. The LED that lights up when the fan is on is also lit full time. Even if I have the harness unplugged.

hmmm I know there was a short period where we had that in the firmware, have you updated your firmware at all? maybe you can update to the latest .91 we have on the downloads link.. if you havent updated the firmware and you have one in the slot when we had that on at all times, maybe an update will bring it to the current where it only turns on with heat.. just brainstorming ideas from what we have done in the past.. and since the light is coming on, its obviously being turned on right away so you may be in that slot where we did that....

Guanu

I uploaded that, still getting the fan on full time. If I send "M42 P6 S0" it still doesn't turn off.