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Wizard stops at hot end after repair to destructive crash  

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Lorenzo
(@lorenzo)
New Member
Wizard stops at hot end after repair to destructive crash

Here is my story in brief form

Overnight print

Run 2+ hours; no problem

Went to bed

Printer went berserk, ripped partial print off bed, deeply scratched bed over entire surface

Melted fan shroud, extruder cover, extruder motor plate, extruder sensor lever, adapter printer and extruder body.

Suspect nozzle being pushed into plate caused it to plug and overheat.

Replaced all of the above parts

Tried to run setup wizard, quit without starting

Factory reset, all data

Flash firmware 3.12, successful

Self test: fans OK, XYZ Axis OK, Home OK, Bed OK,

quits at checking hot end and wants to start over.

Auto home OK

Belt test OK

Will not complete wizard, quits at hot end

Will not preheat

Will not load filament

Flash firmware 3.2 BETA, successful

Thermistor resistance is 165,000 ohms @20 C

Heater resistance is 5.4 ohms @20 C

What needs to be replaced? Help please

Posted : 22/01/2023 12:55 am
Diem
 Diem
(@diem)
Illustrious Member

Have you checked the fuses?

Cheerio,

Posted : 22/01/2023 2:00 am
Lorenzo
(@lorenzo)
New Member
Topic starter answered:
RE: Wizard stops at hot end after repair to destructive crash

What fuses?  It performs many tasks except as described.  The power is there.  I can't find the resistance specs for the heater and thermistor so I don't know if they could be the problem.  I do think the heater resistance may be out of spec. I don't know about the thermistor.

Posted : 22/01/2023 2:07 am
Diem
 Diem
(@diem)
Illustrious Member

https://help.prusa3d.com/article/blown-fuse-mk3-mk3s-mk3s_1925

Cheerio,

Posted : 22/01/2023 2:54 am
Lorenzo
(@lorenzo)
New Member
Topic starter answered:
RE: Wizard stops at hot end after repair to destructive crash

All 4 fuses are good.  If the heater cartridge was partially shorted out, the current would be higher than spec.  24 volts with a 5 ohm R would result in close to 5 amps (120 W)  which is much higher than the 40 W specified.  I can't find the factory specs to verify.

Posted : 22/01/2023 3:31 am
Diem
 Diem
(@diem)
Illustrious Member

All the specs are on Prusa's Github...

For this one contact Prusa Support: Log into your Eshop account, navigate to Help and live chat is at bottom right in most browsers. If not you may need to disable your ad-blocker temporarily.

Cheerio,

Posted : 22/01/2023 1:05 pm
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