Hot end doen't heat up no more/ hotend non si riscalda più

(scrivo in italiano, and try also in english)
Ciao a tutti, alla mia Hephestos2 si è otturato il nozzle col TPE, ho aspettato che l'hotbed si raffreddasse (è utile, ma ha un problema sin dall'installazione: qualsiasi operazione di riscaldamento hotend si blocca quando il nozzle viene a contatto con il bed ancora caldo, quindi bisogna prima aspettare che si raffreddi. Lo dico giusto per informarvi, ma non è questo il mio problema). Ho pulito il nozzle però, adesso, l'hotend non si riscalda più. Ho notato che il termistore si è ormai staccato dall'hotend, e quindi ho approfittato per cambiare l'hotend con uno nuovo che avevo di scorta. Il problema persiste però e non dipende dal termistore, perché ho messo a contatto la punta del saldatore con l'hotend e la temperatura inizia ad alzarsi regolarmente. Ho anche fatto un hard reset, ma nulla. Potreste aiutarmi?
grazie infinite
Hi everyone, on my Hephestos2 the TPE filament clogged up the nozzle, so I've waited for the heatedbed to cool down (heatedbed for this printer is a good new idea from BQ and is useless, but still not perfect, in fact it has a problem: any action that contemplate nozzle to go close the bed, when the bed is still warm, get stopped; for ex. is I stop a print with bed on 65°, and then I restart quickly the print, nozzle get stopped when get close the bed in the middle for the start print calibration that executes before every print. But there's not a problem, it's sufficient to wait the bed to cool down and, after that, I can restart printing. Anyway, Just to tell this to you, but this isn't my problem). So, I've cleaned up the nozzle, but actually the nozzle doesn't heat up anymore! Taking a look closely, I realize that the thermistor get detached from the hotend, so I've thought that I've found the problem, and i've quickly replaced the whole hotend with a new one I bought time ago for a case of emergency like this. But the problem is still there.. also after an "hard reset" from LCD panel, the problem is still there I've also realize that the problem, now with new hotend, doesn't depend on the thermistor, because I've put a welder in contact with the hotend and magically the temperature begins to raise up. So, clearly, the hotend doesn't receive current, "I think"..
Can you help me please??
Thanks a lot..

The Hot-end Mosfet Could have gone Bad. What is your normal TPE temperature reading?

Lets test - set to preheat the nozzle can you measure the voltage across the Nozzle heater connector? Post the the voltage results.
What Controller are you currently using.

---

Computer Programmer / Electronics Technician

Quote
Roberts_Clif
The Hot-end Mosfet Could have gone Bad. What is your normal TPE temperature reading?

Lets test - set to preheat the nozzle can you measure the voltage across the Nozzle heater connector? Post the the voltage results.
What Controller are you currently using.

Thank you so much for the answer,
I do not speak english perfectly, so I have to ask you something about your questions:

"What is your normal TPE temperature reading?"--> I tried to print PTE up to 10° and bed up to 65°. First two layers was good, then the nozzle got clogged (but I'm not sure i've understand your question..)

"can you measure the voltage across the Nozzle heater connector?"--> take a look in the pic I've attached: I have to test on (1), (2) or (3)? And, multimeter on "Ohm", red on red and black on black?

I control the printer with LCD panel printing from SD card.

Thanks for your patience

Edited 1 time(s). Last edit at 07/14/2018 03:26PM by johnleft.

Quote
johnleft


"What is your normal TPE temperature reading?"--> I tried to print PTE up to 10° and bed up to 65°. First two layers was good, then the nozzle got clogged (but I'm not sure i've understand your question..)

"can you measure the voltage across the Nozzle heater connector?"--> take a look in the pic I've attached: I have to test on (1), (2) or (3)? And, multimeter on "Ohm", red on red and black on black?

I control the printer with LCD panel printing from SD card.

Thanks for your patience

At what temperature do you set the nozzle to print TPE filament?

With Multi-meter set to DC Volts Measure voltage across point 1. With 2 & 3 connector/Socket plugged in?
and
With 2 & 3 connector/Socket unplugged. With Multi-meter set to Ohms measure across point 3?

---

Computer Programmer / Electronics Technician

For TPE I used 210°


For the last question: with multimeter set to 200 Ohm, across point 3 I get "05.0", trying also to 2K Ohm I get ".006"


About first and second questions, before I go wrong, tell me if I had understand:

I have to set multimeter to DC V and measure voltage across point 1, first time with 2&3 plugged in and, second time, 2&3 unplugged, right? But, to be sure, I ask: point 1 has to be UNplugged from mother board, right? I do NOT have touch nothing on m.board with the multimeter, right?

thanks a lot

Correct.

It Appears that the Hot-end Heater is 5 ohms, this is where it should measure. So I will assume that the Hot-end Heater is Good.

Now for the DC volt section measure voltage across point 1 with 2&3 Connected and Disconnected.
This will tell if you have voltage without a load and if you have voltage with a load.

---

Computer Programmer / Electronics Technician

So, with multimeter to 20V:

2&3 plugged in:
first time 0.12.... second time 0.07... from third time on, always 0.05

2&3 unplugged:
0.05 but if I move the cables it gives me 0.08... 0.10... 0.04... 0.07... when it get fixed, is 0.05

Quote
Roberts_Clif
It Appears that the Hot-end Heater is 5 ohms, this is where it should measure. So I will assume that the Hot-end Heater is Good.

Now for the DC volt section measure voltage across point 1 with 2&3 Connected and Disconnected.
This will tell if you have voltage without a load and if you have voltage with a load.

I forgot to tell you to set the Preheat filament before you make the measurements. Need to see if the Mosfet is switching on.
And If you have a 24V supply you will need to use the next scale up. to make the measurements.

---

Computer Programmer / Electronics Technician

Quote
johnleft
So, with multimeter to 20V:

2&3 plugged in:
first time 0.12.... second time 0.07... from third time on, always 0.05

2&3 unplugged:
0.05 but if I move the cables it gives me 0.08... 0.10... 0.04... 0.07... when it get fixed, is 0.05

besides this, I've made another test: set multimeter on diode (represented, also, with a "beep"), I've tested point 3 and it made the beep, then I've tested point 1 with 2&3 plugged in, but it made no beep..

Ok I solved the problem, thanks again