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I'm having trouble tracking down a problem with the heated bed in my Rostock Max (v1). Is the component I have circled in this photo used in heating the bed? It's hard to see in the photo but it looks a little bit "bumped up" in the middle with maybe a tiny crack in it... like it has been fried. I'm also unsure of how it is attached. It doesn't look like any solder is on it.

My skill level in soldering is average. Is that something I could replace myself? I've looked up the numbers on the chip but I'm having trouble find one? The numbers are "237" and "S3A". Anyone know what I should be ordering?

It's a surface mounted diode.
It'll be virtually impossible to solder yourself unless you have a hot air rework station. Ultimachine does repair RAMBO boards.

Does the light for the bed come on?

I'm new here and am still learning may way around the RAMBo, but I notice that fuse F3 is missing from the fuseholder. Pretty sure that is for the hot end and not the heat bed, but maybe related to whatever caused the problem...

You can f ind the schematic here: http://reprap.org/wiki/Rambo_v1.2

The purpose of those diodes between power and ground near the fuses is to protect the board from stupid hookup mistakes. Hook up input power correctly, the diode does nothing. Hook up input power backwards, it conducts and causes the fuse to blow immediately instead of letting the circuit fry.

If the fuse isn't blown, the diode is probably not the problem you're looking for. Even if that diode were bad or even missing, the circuit should still work (assuming you never hook up the power backward).

Polygonhell wrote:It's a surface mounted diode.
It'll be virtually impossible to solder yourself unless you have a hot air rework station. Ultimachine does repair RAMBO boards.

Does the light for the bed come on?

Thanks. That's what I was afraid of. No the light doesn't come on.

>> Ultimachine does repair RAMBO boards.

I'd contacted Ultimachine a few days ago but haven't heard back from them yet. They'll probably end up having to fix it.

Eric wrote:You can f ind the schematic here: http://reprap.org/wiki/Rambo_v1.2

The purpose of those diodes between power and ground near the fuses is to protect the board from stupid hookup mistakes. Hook up input power correctly, the diode does nothing. Hook up input power backwards, it conducts and causes the fuse to blow immediately instead of letting the circuit fry.

If the fuse isn't blown, the diode is probably not the problem you're looking for. Even if that diode were bad or even missing, the circuit should still work (assuming you never hook up the power backward).

Thanks. The fuse is still good. I hadn't touched the wiring in a least 6 months when the bed stopped working but I guess some wire could have come loose somewhere. I had printed one part and then when I went to print the next iteration of the part, the bed never heated up.

Earthbound wrote:I'm new here and am still learning may way around the RAMBo, but I notice that fuse F3 is missing from the fuseholder. Pretty sure that is for the hot end and not the heat bed, but maybe related to whatever caused the problem...

That fuse was blown about a year ago and to get things running again I soldered an automotive fuse socket to the fuse. When the board is assembled in the printer, I have that modified fuse plugged into the socket.

Well the 3D Printer gods have smiled on my today. I put the board back in the printer, hooked everything up and it started working again. I'm not going to question it. I never did hear back from Ultimachine.

jetpad wrote:Well the 3D Printer gods have smiled on my today. I put the board back in the printer, hooked everything up and it started working again. I'm not going to question it. I never did hear back from Ultimachine.

I am glad you got it working!