Heater shorted during preheat Prusa MK3+
 
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jmshaffer1973
(@jmshaffer1973)
Active Member
Heater shorted during preheat Prusa MK3+

I'm a little bummed.  I went to preheat when I got home from work so I could unload the filament from a job that completed earlier.  Upon doing so, I heard a little zap.  So, the symptom afterward was I'd try to preheat and the control would reset.  I checked the fuses on the circuit board.  The 15 and both 5 amps were good. I pulled the heater connector and it's a dead short (checked with my fluke).  At this wattage and voltage, I'd expect around 14 ohms resistance.  I just bought this MK3+ about a month ago or so and it's a little disheartening to find out the part is not stocked here.  Is there an aftermarket heater which will work?  Is there any warranty on this?  I've been printing on this thing daily since I got it with no issues, so I'm not sure exactly why the heater shorted out.  The wiring to chassis tests open, so I have no dead short there.  Any help appreciated.

 

Justin

Posted : 29/03/2022 9:39 pm
bobstro
(@bobstro)
Illustrious Member
RE: Heater shorted during preheat Prusa MK3+

If you're in the US, check Filastruder. PrintedSolid and MatterHackers may also have the parts. 

If I'm understanding correctly, it sounds like the 2 heater cartridge wires shorted. They can also get very brittle over time, and are definitely consumables. While you're tearing the hotend down, it's a good opportunity to replace some other parts while you're at it. Depending on the condition of your hotend, removing the cartridge may be difficult if not impossible, so be prepared for a bit of a procedure. It's not hard, but a bit scary the first time. After that, it's a breeze.

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 29/03/2022 9:53 pm
jmshaffer1973
(@jmshaffer1973)
Active Member
Topic starter answered:
RE: Heater shorted during preheat Prusa MK3+

Thanks for the information.  I did pull the heater block and used a heat gun at 550F to loosen the melted plastic so the screw would budge.  I will likely plug the unit back in and see if it acts somewhat normal with the heater disconnected.  I don't think it did any serious damage, but I have a lot of prints to make. I hope they last longer than 6 weeks normally.

Posted : 29/03/2022 10:34 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Heater shorted during preheat Prusa MK3+

Hi Justin, 
the parts are normally stocked by prusa, but there have been shortages, and Prusa may be having difficulty keeping stock... 

Also the parts are low value but expensive shipping, so many people have complained. 

perhaps, prusa have decided not to stock them as they are easily available from other vendors. (Just Guessing)

e3donline have agents in many parts of the world, they can supply heaters and thermistors. 
regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 30/03/2022 10:37 am
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(@-6)
Trusted Member
RE:

Hi Justin. Those parts are in short supply globally. They all come out of the same Chinese factories. There is no reason to get these from Prusa as it is the same stock but just a crazy high premium added and very expensive freight. Keep searching online. You will find it cheaper but may have to wait until end of this month / early April until global stocks resume. The only thing you should buy from Prusa is the Einsy (Rambo) because that is the only thing they make and unfortunately you are forced to buy from the $5 board for $115 from them. That is the silly price we pay for buying prusa. fool me once...

Even the filament granules that prusa use to make their filament come from China so is the same quality as filament sourced directly from China. The +/- accuracy they try to quote is meaningless because the gears that feed the filament dont have that level of accuracy and will push almost anything through (despite what some 'experts' are about to argue this point over). After using 5 printers, I can assure you, filament is filament. 

This post was modified 2 years ago by .
Posted : 30/03/2022 11:04 am
funCoolio
(@funcoolio)
Trusted Member
RE: Heater shorted during preheat Prusa MK3+

@dontbuyprusa: we generally say: "you did it in slices" when too much is too much.

DISCLAIMER:

I am not and will never be an employee of Prusa Research unless they offer me 100K € gross per year. I have friends who built the printer starting from a wooden frame ... that says a lot.

1+1=10 - take a look at my disgusting and useless models

Posted : 30/03/2022 12:01 pm
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(@-6)
Trusted Member
RE: Heater shorted during preheat Prusa MK3+

@funcoolio, "you did it in slices"

Posted : 30/03/2022 12:04 pm
bobstro
(@bobstro)
Illustrious Member
RE: Heater shorted during preheat Prusa MK3+

Do be sure to look for Prusa versions as the cable lengths are different than with standard E3D parts. Thermistor quality can vary, so I'd avoid the cheap generics. I just installed a cheap one on my Sidewinder out of desperation and I'm watching nozzle temps swing +- 10 degrees C while I wait for a quality replacement. 

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 30/03/2022 12:32 pm
jmshaffer1973
(@jmshaffer1973)
Active Member
Topic starter answered:
RE: Heater shorted during preheat Prusa MK3+

roger that! I did find this one has a shorter PTFE tube than the MK3 which is cool because I can just trim 7mm from another hotend then. I did notice some of the aftermarket heating cartridges have slimmer than the 16 g wiring too which stood out as poor quality. I ordered some things from filastruder per one of the recommendations on this thread. Thanks so much. 

Posted : 30/03/2022 9:04 pm
jmshaffer1973
(@jmshaffer1973)
Active Member
Topic starter answered:
RE: Heater shorted during preheat Prusa MK3+

I find your Handle amusing lol. I just ordered another printer though I do like the Prusa printer. I’m a master technician in another field. I question why the heat break wasn’t left hand threaded so loosening a difficult nozzle wouldn’t allow the hot end block to turn too. Weird. I do understand that a wrench should be used and have done so, but it’s an oversight in my opinion since nozzle changes are part of the hobby. Some very small parts I print to coincide or mate with other parts require a nozzle change for utmost accuracy. Either way though, I think the machine is pretty decent. 

Posted : 30/03/2022 9:11 pm
bobstro
(@bobstro)
Illustrious Member
RE: Heater shorted during preheat Prusa MK3+
Posted by: @jmshaffer1973

[...] I question why the heat break wasn’t left hand threaded so loosening a difficult nozzle wouldn’t allow the hot end block to turn too. Weird. I do understand that a wrench should be used and have done so, but it’s an oversight in my opinion since nozzle changes are part of the hobby. 

There are a lot of newer hotend designs that take those factors into account. Prusa used the then-leading E3D V6 design on the Mk3. Newer hotends allow one-handed nozzle swaps, and some are drop-in replacements for the Mk3.

 

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 30/03/2022 9:17 pm
jmshaffer1973
(@jmshaffer1973)
Active Member
Topic starter answered:
RE: Heater shorted during preheat Prusa MK3+

I don’t know much about aftermarket parts. Sounds like you do. Any good recommendations?

Posted : 30/03/2022 9:21 pm
bobstro
(@bobstro)
Illustrious Member
RE: Heater shorted during preheat Prusa MK3+
Posted by: @jmshaffer1973

I don’t know much about aftermarket parts. Sounds like you do. Any good recommendations?

The Dragon hotends were a big deal a while ago. The Revo seems to be the latest hot news. I haven't tried one, but there are a lot of posts here on using them on the Mk3 & Mini.

 

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 30/03/2022 10:21 pm
Thejiral
(@thejiral)
Noble Member
RE: Heater shorted during preheat Prusa MK3+

@DBP

You keep repeating your claim that the value of the Einsy board is 5 EUR. That may or may not be the actual production cost, however given that the Bigtreetech SKR Mini V2.0 is hard to get for under 40 EUR, even directly from the Chinese manufacturer, + shipping costs on top (even on Ali), I doubt that this claim is well founded. The premium for the Einsy board is more like a a factor of 2 or so, given that it is already imported to the EU. And just because it is an 8bit board doesn't mean it would be cheaper to get, only that it is a bit dated in terms of specification. 

Mk3s MMU2s, Voron 0.1, Voron 2.4

Posted : 31/03/2022 10:38 am
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(@-6)
Trusted Member
RE: Heater shorted during preheat Prusa MK3+

Thanks therijal. Your post was very helpful and informative... Oh wait no it wasn't. It was just criticism. Good trolling loser. You troll, I anti-troll. But keep going, I will definitely stop sticking up to bullying (not)

Posted : 31/03/2022 11:10 am
Thejiral
(@thejiral)
Noble Member
RE: Heater shorted during preheat Prusa MK3+

My comment was not about you but about your claim of 5 USD Einsys. Seems the Chinese manufacturer of decent quality printer boards was ripping me off with charging more than 40 USD for a control board. Just had a look at AliExpress. It's 44 EUR now. 

Mk3s MMU2s, Voron 0.1, Voron 2.4

Posted : 31/03/2022 1:56 pm
bobstro
(@bobstro)
Illustrious Member
Actual price of replacement boards
Posted by: @thejiral

[...] Seems the Chinese manufacturer of decent quality printer boards was ripping me off with charging more than 40 USD for a control board. Just had a look at AliExpress. It's 44 EUR now. 

The Prusa knowledgebase indicates the Einsy RAMBo is manufactured by UltiMachine. A bare board can be purchased directly from UltiMachine for $110, or $119 from Prusa (with a plug aligner). The same board sells for $125 on Amazon and even a clone is $119. Various clones go for around $78 on AliExpressalthough they don't seem to be of very good quality. I'd be very leery of anything much cheaper given the reviews.

I'd love to find a source for RAMBos for $5. If anybody has actually found them that cheap, please post a link! In the meantime, buying from Prusa makes sense in terms of warranty coverage and support.

 

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 31/03/2022 3:14 pm
Thejiral liked
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 .
(@-6)
Trusted Member
RE: Heater shorted during preheat Prusa MK3+

Well clearly everything voids warranty and there is no customer service so don't but prusa

Posted : 31/03/2022 8:51 pm
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