Power supply shorting

[RSMaxwell]

I have finished building my Rostock Max and began the software portion. When I went to power on, nothing apparently happened. To make a long story short, if I have any power going to the heated bed connections (the power in on the sides, not the power outs on top) the power supply trips its protection circuit.

I have tried one yellow -- it trips. I have tried one of the other 12v wires -- it trips. I've tried unplugging everything from the RAMBo, and it still trips. As long as nothing is in that heated bed power input, everything is fine. Any ideas?

[cambo3d]

can you show me a photo of the traces on the back of the rambo board where the heatbed power inputs are located.
and also show me how you have your wires connected.

[magicmushroom666]

The pads top and bottom are connected together, they are not in on the bottom and out on the top. You need to connect to one side only, either the top or the bottom, and one wire from each to one terminal on the rambo.

[RSMaxwell]

The pads top and bottom are connected together, they are not in on the bottom and out on the top. You need to connect to one side only, either the top or the bottom, and one wire from each to one terminal on the rambo.

I am so confused by this. I guess that I did not explain well.

The issue is with the "heat bed" in the area marked "power input". This happens even if I have nothing in any of the "MOSFET outputs". In fact, I disconnected everything except the power inputs and it still happens.

[Jimustanguitar]

The pads top and bottom are connected together, they are not in on the bottom and out on the top. You need to connect to one side only, either the top or the bottom, and one wire from each to one terminal on the rambo.

He's talking about the power inputs and outouts on the Rambo, not the connections on the heated bed itself. The inouts are in the side and the output from the Rambo to the heated bed is on the top.

I've seen a few bad Phoenix connectors before. Check for continuity between the terminals just in case.

I had a bad power supply, so test if it trips under any sudden load. I.E. power it up without the bed plugged in at all and try to home the axes or heat the hotend. That would trip the supply on my bad one.

[Eaglezsoar]

You have a short on the card. Unless you are familiar with electronics I would contact the vendor about replacing the card.
Schematics are available at the Rambo Wiki but if you are not experienced in troubleshooting the vendor is your only option.

[RSMaxwell]

can you show me a photo of the traces on the back of the rambo board where the heatbed power inputs are located.
and also show me how you have your wires connected.

I have three yellow 12v wires twisted together and soldered. I have tried using a single yellow, but no luck. Everything else seems to work so long as the heat bed power inputs are not plugged in. I have the LCD harness wired up, but not plugged in. I also added an LED indicator while I was troubleshooting, and I did not know that the jumper needed to be switched from USB to PSU.

Back (with glare):

[img]http://i1297.photobucket.com/albums/ag2 ... d14861.jpg[/img]

Working RAMBo board (without heat bed power):

[img]http://i1297.photobucket.com/albums/ag2 ... 114057.jpg[/img]

Close up of the power connector without the heat bed power:

[img]http://i1297.photobucket.com/albums/ag2 ... 2c8002.jpg[/img][/url]

[RSMaxwell]

You have a short on the card. Unless you are familiar with electronics I would contact the vendor about replacing the card.
Schematics are available at the Rambo Wiki but if you are not experienced in troubleshooting the vendor is your only option.

I'm afraid you were going to say that. I'm familiar enough with electronics to know not to fry anything, and not to poke around at things that I do not understand.

By vendor, are you referring to SeeMeCNC?

[Eaglezsoar]

You have a short on the card. Unless you are familiar with electronics I would contact the vendor about replacing the card.
Schematics are available at the Rambo Wiki but if you are not experienced in troubleshooting the vendor is your only option.

I'm afraid you were going to say that. I'm familiar enough with electronics to know not to fry anything, and not to poke around at things that I do not understand.

By vendor, are you referring to SeeMeCNC?

Yes, Seemecnc. They will send you a new card. You can reach them at [email protected] or call them.
Their number is listed on the website. They will most likely want to test the card so make sure you describe the
exact problem you are having. It sounds like the Mosfet that drives the Heat Bed is shorted or a trace on the card is shorted but if you try to troubleshoot
you could make things worse and void the warranty on the card. Sorry for the bad news but you don't have many options.

[RSMaxwell]

I wrote SeeMeCNC. So far no reply. Bummer. I hope they are away as opposed to ignoring me.

[Eaglezsoar]

They will get back to you. They are busy people but I know of no circumstance where they ignored a request for support.

[RSMaxwell]

The fastest way for me to get a response is to say "why haven't I got a response?" There is a cosmic joke against me here. About 30 seconds prior to hitting the send button of my last post, I John sent me a reply. .