Burned out board

[M. Beneteau]

Hi all, New to this forum but not to 3d printing...LOL.
I just switches out a 40mm fan and the board burned out after a short. The supply plugin at back of board was fried brittle and the only response is the lcd screen with readings. Does anyone have a solution...help please.
Thanks,
Mike

[insta]

Do you have a 12 or 24v machine?

[Tim]

the only response is the lcd screen with readings.

I'm going to assume that you have the right voltage fan, etc., and the problem was caused by a known accidental short.

Are the readings on the LCD screen meaningful? Do fans and such turn on upon power-up, or is it totally dead other than the LCD screen? I don't have an LCD screen, so I don't know where its power comes from. Could it be powering through the USB? There are several fuses on the RAMBo, one of them an easily-replaceable automotive fuse and another two that you are unlikely to find outside an electronics supplier like Newark or Digi-Key. Take a look at the page http://reprap.org/wiki/Rambo_v1.2. Replacing a fuse will be a lot easier than buying a new board, so check the fuses before going shopping for a new RAMBo!

[jimc]

to help the OP and anyone else needing the info down the road........yes they are called nanofuses and mfg by littlefuse. they are only about a 1/4" long. they are white centers with gold or silver ends and are square instead of round. i believe there are 2 of them on the board. as tim said be sure to check those first. i have some i got from newark.com about a year ago. if they are bad the part # is 0448005.MR

[M. Beneteau]

Hey Thanks for the info. all. I am in contact with Josh at the moment. I took out my multimeter and checked power source. Seems i am getting power from lcd power supply (12V) but nothing from the 19v supply 4 contact plug. Is there a fix for that? Thanks. BTW the 15a fuse is fine. Where are the nanofuses located? Anybody have an idea where i can get a Rambo board v1.2 (i am supposing that is what MG m2 uses) for a good price. They are around a 180$ here in Canada.
Thanks for all info.
Mike

[M. Beneteau]

Tim wrote:
I'm going to assume that you have the right voltage fan, etc., and the problem was caused by a known accidental short.

Are the readings on the LCD screen meaningful? Do fans and such turn on upon power-up, or is it totally dead other than the LCD screen? I don't have an LCD screen, so I don't know where its power comes from. Could it be powering through the USB? There are several fuses on the RAMBo, one of them an easily-replaceable automotive fuse and another two that you are unlikely to find outside an electronics supplier like Newark or Digi-Key. Take a look at the page http://reprap.org/wiki/Rambo_v1.2. Replacing a fuse will be a lot easier than buying a new board, so check the fuses before going shopping for a new RAMBo!

Yes, the fan was one of MG; 12v. As to a known accidental short; not sure what that entails but can tell you that 12v supply dual plugin to board was fried crisp and 19v quad supply doesn't register on multimeter (see previous post).
The LCD has its own power through board. 15A fuse is ok.
How do I verify other fuses without disconnecting all the inputs in board?
Thanks,
Mike

[insta]

Hey Thanks for the info. all. I am in contact with Josh at the moment. I took out my multimeter and checked power source. Seems i am getting power from lcd power supply (12V) but nothing from the 19v supply 4 contact plug. Is there a fix for that? Thanks. BTW the 15a fuse is fine. Where are the nanofuses located? Anybody have an idea where i can get a Rambo board v1.2 (i am supposing that is what MG m2 uses) for a good price. They are around a 180$ here in Canada.
Thanks for all info.
Mike

Send MG an email directly (karen [at] makergear.com), explain the situation, and see what the price is. They're a lot cheaper for replacements than retail...

[Tim]

How do I verify other fuses without disconnecting all the inputs in board?

I can't entirely vouch for that because I have an older board, but I think the nanofuses are the same. They look like surface-mount devices that are plugged into a beige-colored socket; I haven't tried but I assume you can just pull them out with a small pair of needle-nosed pliers. Or since the connectors are exposed on top, you can just touch a multimeter to them and measure the resistance across it. If it's < 1 ohm, it's good; if it's >> 1 ohm, almost certainly shot.

By "known accidental short", I meant that you know what happened; i.e., wires came loose and touched, or something was accidentally plugged in backwards, that you know about after the fact. However, it sounds more like your input connector fried and you don't know what happened other than it fried. But---you have the 19V/12V split supply, and those are known to be prone to melting the input connector if it comes loose. If, as you say, you are not measuring 19V at the input, then the most likely thing to have broken is the wiring. Power bricks are rather difficult to destroy, and the wires are more likely to melt first, or the terminals get coated with carbon and break the connection. You might try cutting off the wires and stripping them back well beyond the burned point, and see if you can measure 19V from the power brick there.

[M. Beneteau]

Hi all,
I am having problems with my 12v supply block connector; it keeps burning out -- cannot tolerate current going through it. These are replacement 2pin block connectors from the local e store. Does anyone have a quick solution? Or where to get 2pin block connectors in Canada that can tolerate the 5A current?
Thanks,
Mike

[M. Beneteau]

Thanks, Tim You were correct; pins were coated with carbon(melted plastic) and the one micro fuse was burnt.
I am still having problems with the block connector; see previous message.
I am getting proper voltage now from supply; thanks.
Do you have any suggestions?
Someone suggested removing pins from board and replacing with molex connectors to avoid coming loose and to support extra current. Does this make sense?

TTYS,
Mike