Replaced heater block, hot end heater and thermistor - now failing self test!!!
 
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Replaced heater block, hot end heater and thermistor - now failing self test!!!  

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PCB
 PCB
(@pcb)
Active Member
Replaced heater block, hot end heater and thermistor - now failing self test!!!

After stupidly cross threading my original prusa heater block I replaced the original with a stainless steel block and for good measure replaced both hot end heater and the thermistor (prusa parts). Replacement all seemed to go well but now i keep getting a repeated self test error Heater/Thermistor not connected. I have double checked the installation and after reading the forums also did a factory reset but still self test fails. I have done a preheat for PLA and the hot end reached and stabilised at 215C. Any tips? 

 

Do I just ignore and carry on with calibration

Posted : 23/11/2021 5:00 pm
Diem
 Diem
(@diem)
Illustrious Member
RE:

Heater/Thermistor not connected

This tells us the signal is not getting through, if the heater is OK it must be the thermistor.

Check the connections and if they are all correct check the resistance of the part with a multimeter.  You are looking for a resistance, not an open circuit or a short.

Cheerio,

Posted : 23/11/2021 6:02 pm
Jerry
(@jerry)
Estimable Member
RE: Replaced heater block, hot end heater and thermistor - now failing self test!!!

Tell me more about the stainless steel heater block?

Posted : 23/11/2021 7:44 pm
PCB
 PCB
(@pcb)
Active Member
Topic starter answered:
RE: Replaced heater block, hot end heater and thermistor - now failing self test!!!

It is this part from Ooznest 

https://ooznest.co.uk/product/e3d-v6-stainless-steel-heater-block/

Posted : 24/11/2021 10:23 am
PCB
 PCB
(@pcb)
Active Member
Topic starter answered:
RE: Replaced heater block, hot end heater and thermistor - now failing self test!!!

Thanks Diem, just measured and it's pretty much identical to the old thermistor. Resistance changes with temperature change as expected, so the fault doesn't lie with the thermistor.

Posted : 24/11/2021 10:46 am
Diem
 Diem
(@diem)
Illustrious Member

If the part is OK and the connections are OK then double check you haven't mixed up the two thermistor sockets:

https://help.prusa3d.com/en/article/einsy-rambo-electronics-wiring-mk3-mk3s-mk3s_2107

and then inspect the socket itself for damage.

After that your recourse is to Prusa Support: Log into your Eshop account, navigate to support and live chat is at bottom right in most browsers. If not you may need to disable your ad-blocker temporarily.

Cheerio,

Posted : 24/11/2021 12:52 pm
PCB
 PCB
(@pcb)
Active Member
Topic starter answered:
RE: Replaced heater block, hot end heater and thermistor - now failing self test!!!

So I thought I'd just provide an update in case anyone has the same problem in the future. 

I replaced my aluminium heater block with a stainless steel model and after replacing the thermistor and heater kept getting a self test error. Following suggestions on the forum (thanks to all) I tried the Prusa support and spent about two hours working step by step with Simon (top support guy), testing connectivity, POWER SAFE, resistance and voltage levels across various terminals finally concluded all was connected and working correctly......so must be something in the self test parameters.....and it is a time out flag. The stainless block takes longer to heat up and consequently the return form the thermistor appears that the heater isn't working correctly. I tried printing  with PLA and PETG some test prints and all was working fine for short prints but anything over 30 minutes ended up with thermal runaway error or poor/defective print. I had some items to print so ordered a new aluminium heater block and replaced the stainless block. Self test worked perfectly. Printer working absolutely fine again. Hope this helps.

Posted : 01/12/2021 11:08 am
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