power on rambo board problem ?

[spart]

ok having a bit of a brain scratcher

turned on power supply and the light didn't come on on the power supply when plugged into rambo board. unplugged the rambo power lead and power supply light comes on, not to sure if there is a light on the rambo board that comes on when has power but none came on but power supply making cracking sound when hooked up to board only so turn off. has anyone any clue on this or have run into this problem before

[Eaglezsoar]

Verify that the wires from the supply going to the rambo are not reversed. Yellow to plus, black to minus is correct.
If the wires are fine then it sounds as though there is a short somewhere on the rambo. Visually inspect the board
and make sure that there are no wire strands shorting together. If you don't see anything wrong then my next step
would be to use an ohm meter and with all the wires disconnected I would measure with the ohm meter the power in
connectors. I predict that you will measure 0 ohms or close to 0, indicating a short. If you find the board has a short
on the inputs I'm sorry but you will have to send the Rambo back to the vendor if it is still under warranty.

[spart]

thanks i unplugged all my connection to the board and looks like one of them must be grounding out somewhere, got to go back and check every dam thing, power comes on now when connected to broad thank god. ? what should power be reading to come into board i am siting at 12.24 on all three leads haven't adjusted anything on power supply .

[Eaglezsoar]

The power should be around what you are seeing. I do not know what you did to fix it but I am glad the board is
not shorted. Regards.

[spart]

back tracked it to my hotend wires once i plugged it in it started doing it again so going to rewire, every thing else seems to not shut down the power supply at this piont. should i be getting any type of light on the board at this point. i have not connected it yet to the computer.

[Eaglezsoar]

I am surprised that the fuse to the Hotend did not blow on the Rambo. I'm not sure what lights on the Rambo would be on without it
being connected to the computer. Can someone who is reading this thread and knows what the Led status should be with just the
power applied please jump in with your comments.

[SlowFollower]

I would like to know the answer to the LED question as well.

I have an old kit that I just put together. Rostock V1
I turned it on for the first time to start loading software and the screen did not light up.

The power supply fan turns on. No other sounds from the power supply.
I have 12VDC across all three individual power inputs.
All three fuses are still good.
The green LED only lights up if I have the computer hooked to the USB. When I disconnect the USB the light goes off.
In troubleshooting I have disconnected all the other outputs, motors, thermistors, LCD, switches... The RAMBO board is disconnected except for the power.

Should there be any kind of light indicating that the board has power?

Also, this is my first post so tell me if I should have posted elsewhere first.

[skyjuice]

Similar problem here as well. No led lights on board. Fan under it turns on and the hot end lights up. This is a brand new hot end with a brand spankin new whip and RAMBo from Ultimachine. I tested the power coming into the board and it's a solid 12.4v, but doesn't seem to want to go any farther than the 8 pin plug where it comes it at. I have meticulously scanned the entire board for a short of any kind and came up empty handed. I am baffled. Ideas?

[joe]

How about posting a pic of the rambo with all the wires hooked up.

[Eric]

Slowfollower, as you do have an ancient kit, it also means you probably have an old version of the Rambo board. Prior to version 1.2, there was a jumper to select logic power from either USB or the PSU. It was a feature, in combination with the original function of the PS_ON connector, that allowed the Rambo board to be in charge of turning the ATX printer power supply on or off as part of the g-code program. In practice it caused more confusion than actual benefit, which is likely why it was designed out of later versions of the board.

Anyway, it sounds like your jumper is in the USB position, which means USB power must remain attached to operate the printer. Change that to PSU operation and I bet your issue goes away. Here's a crica 2012 Rambo diagram...note the jumper on the left side and the associated text: http://reprap.org/wiki/File:Rambo-conn-all.jpg

Skyjuice, this thread isn't relevant to your issues with your V3. Slows revival of this FOUR YEAR OLD thread is only relevant because he's got a really old version of the kit.