Had a bit of a scare this morning when my Ramps Board, the capicitor shown in the photo, started to smoke. Printer has been working well prior to this incident. Both the hot end and the heated bed were coming up to temperature/ Resistance across the heated bed is reading 1.7 ohms and the hot end around 5 ohms.



I have powered things back up and both the hot end and heated bed appear to be working though I have not done another print yet!

Any ideas / suggestions
Wisar

That is not a capacitor, it is a fuse (a self resetting one). Note the annotation next to it F2, if it were a capacitor it would be C2. If I were you I would replace it and check all the tracks and cables for shorts.

Thats your 11amp fuse.

This is used for the HBP only...

Im surprised your bed is still working... I would replace the fuse asap.

Fuse! I did not even check the nomenclature. Thought it looked like a big ceramic capacitor. Will replace it...but...I still dont understand what set it off in the first place! I will check all leads for shorts which I guess is what one would assume happened?

Thanks,
Wisar

You need a fan blowing continuously across the Ramps board. These fuses will eventually start breaking down and shutting off the heat bed if they are not cooled. (helps to cool the Mosfets too)

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Waitaki 3D Printer

The heat bed mosfet is notoriously bad on the RAMPS board. I had one get so hot it desoldered itself from the pcb. The polyfuse also got really hot, I'm assuming that it was going flat out setting/resetting itself. So first thing I would do is replace the mosfet with one like a IRLB8743PBF, then replace the polyfuse with an external one (glass tube or automotive blade type). I have a fan blowing directly down onto the board, but it runs nice and cool since replacing the mosfet, even when running the heat bed for the entire print run.

I do have a fan running across the electronics. When the fuse went it had only just started a job and I don't think it was that hot at all. I am printing PLA so it really has not had to work very hard.
I think that I will go the external fuse route and I think I will add a heat and smoke detector to the board as well...

Wisar

Edited 2 time(s). Last edit at 05/12/2014 06:00AM by Wisar.

Not sure if this is the chicken or an egg but I continued to have intermittant problems with the heated bed following the smoke above. I have a new one on order but the old one seemed to still be working...but...it would occaisionally go dark. I traced this back to what I though was loose wiring but it turns out the power in socket was smoked.



Not sure if there was a short circuit here that caused the problem with the fuse or if something else caused both the fuse and the socket to smoke. The printer is working well now though I have added a smoke detector and heat detector that sit right above the electronics stack and will trip the power supply off if things smoke again.

Wisar

So I'm setting up my RAMPS Board. I was an idiot and plugged in an endstop incorrectly and I heard some sparks and the blue smoke started coming out of the bottom of my RAMPS Board. What just happened and how can I fix it?

FYI: I had plugged the endstop into -&+ instead of S&-. And it was turned on and plugged into the power supply.

Probably barbecued the voltage regulator on the Arduino..

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Waitaki 3D Printer

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waitaki
Probably barbecued the voltage regulator on the Arduino..

Crap. What can I do?

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BradStaff
Crap. What can I do?

Replace the voltage regulator.

Yeah it is the voltage regulator. How should I replace it?

Would this be a good one to get?
[store.gravitech.us]

it should be an LM1117 right next to the power jack on the mega. get em from ebay. be careful when you remove the original. snip the 3 leads, then add some solder when hot and gently remove. then heat the big tab, add solder then gently lift it off. if you try to lift the leads without adding 60/40 solder the rohs solder wont melt well and you risk tearing the surface mount pads off of the board.

LM1117 on EBAY