My hotend is broken. Can I fix this or do I need to buy a new one? Troubleshoot help?
 
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My hotend is broken. Can I fix this or do I need to buy a new one? Troubleshoot help?  

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yakurbe
(@yakurbe)
New Member
My hotend is broken. Can I fix this or do I need to buy a new one? Troubleshoot help?

There was a spark on the heat block and now whenever I try to heat it up, the machine restarts. Aside from that, everything seems fine (it ran through a selftest up to that point no problem) so I don't think I fried the board or anything, but I obviously can't print as is. The thermistor seems fine too.

Can I fix this? Does it seem like I know what broke, or are there other things I need to check? Is it worth fixing instead of buying a new one? If so, how exactly would I do that? I kinda don't know what I'm doing at all.

Posted : 03/05/2021 7:05 am
TyrkysLabs
(@tyrkyslabs)
New Member
RE: My hotend is broken. Can I fix this or do I need to buy a new one? Troubleshoot help?

Sounds like heating element issue. The wires probably moved around and broke off. Make sure the wires are secured properly and do not move when the extruder moves around. You might be able to fix it by soldering or simply pushing the broken connection back together. This is very temporary fix but might work somehow. I recommend you do yourself a favour and buy a new heating element or new hotend. 

This post was modified 7 months ago by TyrkysLabs
Posted : 03/05/2021 7:38 am
Clarmrrsn
(@clarmrrsn)
Honorable Member
RE: My hotend is broken. Can I fix this or do I need to buy a new one? Troubleshoot help?

I would suggest inspecting the cabling around the hotend, there is possibly a break in the insulation on either the heater or thermistor cable which may have shorted on the heatblock.  Did you get any print head crashes prior to this happening that could have damaged the cable?

If the insulation is damaged I would replace the component that is damaged, there should not be a need to replace the entire hot end. However there is a chance that the board is damaged after the short.  Sparks normally are not without consequences.

Feel free to post some photos of the cables around the heatblock.  Although really needs a good close inspection of sll sides of the cable to look for damage and we cant do that for you,

This post was modified 7 months ago by Clarmrrsn
Tank you very much!...
Posted : 03/05/2021 8:48 am
Clarmrrsn
(@clarmrrsn)
Honorable Member
RE: My hotend is broken. Can I fix this or do I need to buy a new one? Troubleshoot help?

You also have the option of live chat support with Prusa.

If you are not confident this may be your best option, they can assist you live with some diagnosis.

EShop, appears in bottom right after a few seconds.

Tank you very much!...
Posted : 03/05/2021 9:00 am
Clarmrrsn
(@clarmrrsn)
Honorable Member
RE: My hotend is broken. Can I fix this or do I need to buy a new one? Troubleshoot help?

@yakurbe

Please dont, as suggested above "push the broken connection back together"

This is unsafe, and could result in further damage.

Replace the thermistor and/or heater with new Prusa parts, or solder to ensure a good connection and heatshrink to insulate if effecting a repair.

A loose 24v connection can generate a lot of heat, you need to make sure any repair is performed correctly.

 

Tank you very much!...
Posted : 03/05/2021 4:31 pm
Diem
 Diem
(@diem)
Noble Member
RE: My hotend is broken. Can I fix this or do I need to buy a new one? Troubleshoot help?

... and check the fuses on the Einsy board, if you are lucky one has blown and protected the rest.  Replace if so.

You can pull the hotend power connection (red wires) and check it with a multimeter but I'd be inclined to replace it in any case.  If the multimeter shows a closed circuit DO NOT RECONNECT, if open, check the wires, repair if possible and recheck.

If you get a resistance note the value and contact Prusa support, they will advise you if they think it's safe to continue.

The big risk is that of fire.  Unwatched, sparking equipment is dangerous.

Log in to your Eshop account, go to support and open a chat session - bottom right in most browsers.

Cheerio,

Posted : 04/05/2021 6:58 am
Clarmrrsn liked
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(@)
Illustrious Member
RE: My hotend is broken. Can I fix this or do I need to buy a new one? Troubleshoot help?

If the spark was long and hot, then there is also a very good chance you've destroyed the Rambo - the heater driver mosfet will fail, yet the fuses will still test good.  The short circuit is enough to shut down the power supply, but not blow fuses. In many ways, the fuses are redundant to the power supply over-current regulator.  Or sometimes the mosfets fail in an open condition. Check if the heater leds are turning on on the Rambo. I think they are the amber ones, not the two green at the top of the board.

Then again - you said the printer starts, but when it tries to warm things up, it resets.  This is a pretty classic driver fail, or odd chance the arc welded something and caused a permanent short.  Do you have an ohm meter and know how to use it?

This post was modified 7 months ago by --
Posted : 04/05/2021 7:09 am
TwoBallScrewBall
(@twoballscrewball)
Trusted Member
RE: My hotend is broken. Can I fix this or do I need to buy a new one? Troubleshoot help?

As was said, check the heavy red wires to the heater element.   The thermistor does not carry enough current to spark.   

You might be able to get away with just replacing the heating element if your heater block is in decent shape.   Here's one on Amazon, of course they're also available direct from Prusa.  Regardless of which one you buy, you have to swap the connector from the old one to the new one. 

https://www.amazon.com/Genuine-E3D-Heater-Cartridge-HEATER-24V-40W/dp/B07FTR2YJG/

If that doesn't fix you up, you might have damaged the electronics as others have said.  

I would for sure stop powering on the printer / hot end until you get this fixed.   Shorting the heater wires can for sure cook things pretty quick. 

Posted : 04/05/2021 10:38 pm
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(@)
Illustrious Member
RE: My hotend is broken. Can I fix this or do I need to buy a new one? Troubleshoot help?

If you look at the heater closely, you'll see the wires are not insulated where they enter the filler. Sure, there's a fiberglass sheath, but it moves and exposes the bare wires quite easily. These bare wires are in turn easily contacted when using brass brushes to clean the nozzle - and why such cleaning should only be done when the printer is powered down. Otherwise, use paper or cloth to clean the hotend when at temp.

Posted : 04/05/2021 11:25 pm
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