I just got a K8400 a week ago. I decided to buy a heated bed, the reprap mk3 plus the power expander, power supply and thermistor.
The issue I am having is that I think something is wrong with the motherboard, and by this i mean the software settings or something.
I tested the bed with a 5v input signal through the power expander and it started heating up perfectly.
I then connected everything, and mounted the wires from the thermistor to the motherboard and the wires from the signal-input on the power expander. Nothing…
I then checked with a multimeter to see if there were any voltage from the pins. There wasn’t.
I used the guide at the wiki which states that 2 lines of code have to bed added to the G-Code.
you do need to add the G-code to cura which can be done by going to slicer/config/g-codes and edit from there. you will need to do both start and end g code
i found this link pretty helpful to check everything with
hope that helps
luke
(Note: you will need to check the heatbeds temp with a temp gun i have found mine can vary from what the thermistor thinks so invested in a temp gun
Hey
Got it working last night, oddly enough the only thing i did was adding T1 to the Line reffered to in the wikiguide, now it was picking up the thermistor readings, albeit they about 15 degrees off…
This is easily corrected by just using a lower temp setting.
Unless you guys have a way of changing the readout so it is correct.
Unfortunately I broke off the soldering point for the thermistor… Too much heat i guess! So I ordrered a new heatbed, along with a solder with variable temp.
Do you guys have any advice for soldering the thermistor on??
Be carefull, be fast and use the smallest tip for the soldering iron you can find. Start by adding some solder to the solder point on the mk3. Then place the thermistor carefully at the correct position. Hold it down with a tool in one hand while heating one solder point and thermistor at the same time. Repeat on the other side.
Good luck !
the thermistors are ceramic and dont like being heated up too fast, they fracture hence the end coming off, i made the same mistake using my workhorse iron on the first one,
ideally they need reflow soldering on, but! they can still be soldered manually, just use an iron with a variable temp and turn down the heat,
Monza has the right advice for it as the thermistors are pre soldered the solder added to the board should flow straight onto it,
only thing i’d add would be not to solder both pads first only solder the one, as you can only heat one at a time you will add pressure to the first solder, or end up with the thermistor not flush on the bottom of the bed, when you have soldered the first pad you can then add the solder to the second without having to push it down onto the bed (not sure if that makes sense its tricky to explain)
and as for the temp adjustment, you can set the profile on the firmware to pick up the correct temp, i haven’t done this as its hard to define exactly which profile would suit, but if anyone does have a guide on this i would like to see it!
[quote=“Andreas93”]Hey
Got it working last night, oddly enough the only thing i did was adding T1 to the Line reffered to in the wikiguide, now it was picking up the thermistor readings, albeit they about 15 degrees off…
This is easily corrected by just using a lower temp setting.
Unless you guys have a way of changing the readout so it is correct.
Unfortunately I broke off the soldering point for the thermistor… Too much heat i guess! So I ordrered a new heatbed, along with a solder with variable temp.
Do you guys have any advice for soldering the thermistor on??
Much appreciated
Andreas[/quote]
Hello Andreas93
I bought MK3 preassembled heated bed from reprap.me. It has already soldered thermistor to the bottom of the bed. However I have no clue where on the board to connect it to. Any advice please ?
Thanks in advance,
Darek
