ST3Di Modelsmart 280 - Duet Maestro repair/upgrade

jay_s_uk

you may have to either take a punt on the thermistors as something like 3950's or 4092's.
Other than that you'll have to change them so you know exactly what you they are.
I've just had a quick google and nothing has come up.

Veti

first measure the resistance at room temperature so that you can determine that it is a 100k ntc thermistor

Blacksheep99

@Veti said in ST3Di Modelsmart 280 - Duet Maestro repair/upgrade:

thats the difficult part.

is there any way you can get documentation as to what the exact model number is of the thermistor?

Would there be anything on the part itself to provide a clue? I can go check.

I changed the R25 number based on what I'd seen others use. On initial test of the bed heater it threw an error as heating too slowly. I ran autotune and it then would heat up to 80c without error. I've a lot to learn.....

Veti

@Blacksheep99 said in ST3Di Modelsmart 280 - Duet Maestro repair/upgrade:

I changed the R25 number based on what I'd seen others use.

the settings are specific for your thermistor model.

Blacksheep99

@Veti to be clear, on the bed there are the power cables and then the thermistor cables right?

Blacksheep99

@Veti said in ST3Di Modelsmart 280 - Duet Maestro repair/upgrade:

@Blacksheep99 said in ST3Di Modelsmart 280 - Duet Maestro repair/upgrade:

I changed the R25 number based on what I'd seen others use.

the settings are specific for your thermistor model.

Understood, thanks.

Veti

@Blacksheep99 said in ST3Di Modelsmart 280 - Duet Maestro repair/upgrade:

to be clear, on the bed there are the power cables and then the thermistor cables right?

that is normally the case

Veti

can you post a picture of the thermistor?

Blacksheep99

Blacksheep99

Each heater is 120x150mm

dc42

@Blacksheep99 said in ST3Di Modelsmart 280 - Duet Maestro repair/upgrade:

The probe\end stop has one but shared power circuits, the servo has a single feed to one pin with shared power, the hot ends have a single pin but share power also.

Shared +5V or +3.3v power and ground to the Z probe and the endstops is OK, if they use the same power voltage. Sharing power with the servo is also OK if they all need +5V power.

Shared +VIN power to two heaters is OK as long as the cable can handle the current for two heaters.

Blacksheep99

@dc42 said in ST3Di Modelsmart 280 - Duet Maestro repair/upgrade:

@Blacksheep99 said in ST3Di Modelsmart 280 - Duet Maestro repair/upgrade:

The probe\end stop has one but shared power circuits, the servo has a single feed to one pin with shared power, the hot ends have a single pin but share power also.

Shared +5V or +3.3v power and ground to the Z probe and the endstops is OK, if they use the same power voltage. Sharing power with the servo is also OK if they all need +5V power.

Shared +VIN power to two heaters is OK as long as the cable can handle the current for two heaters.

Thanks @dc42 I'll check the above. The two heaters are using the installed cabling so I should assume that it is up to the task. I am using the same PSU etc.

Blacksheep99

It has been mentioned in one of my other threads but worth me double checking. With my 24v psu I will need to change the fans on the printer to 24v also? the current ones are 12v. I think it's easier to replace than buy a converter?

jay_s_uk

Either way to be honest.
My preference is to use the correct voltage fans but other people are happy with buck converters

Veti

have you measured the resistance ?

Blacksheep99

@Veti said in ST3Di Modelsmart 280 - Duet Maestro repair/upgrade:

have you measured the resistance ?

169.1 Kohms If i read it correctly. That is at room temp which is cool today as there's no heating on at the moment in that room.

Veti

modules:composer.user_said_in, @Blacksheep99, ST3Di Modelsmart 280 - Duet Maestro repair/upgrade

That is at room temp which is cool today as there's no heating on at the moment in that room.

which is about what temperature?

Blacksheep99

@Veti thermostat in that room says 12c

Blacksheep99

@jay_s_uk said in ST3Di Modelsmart 280 - Duet Maestro repair/upgrade:

Either way to be honest.
My preference is to use the correct voltage fans but other people are happy with buck converters

I think I side with you. I'll order some fans

Veti

ok thats inline with a 100k ntc thermistor.

but which one is not as easy to determine.

can you put the thermistor at 100C using a known good temperature measuring tool?

i.e here is a beta 3950 resistance table.
https://www.keenovo.com/NTC-Thermistor-R-T-Table.pdf