After printing ABS for a while (most of the time it failed), I thought it was time to add a heated bed to my vertex k8400.
I bought a mk3 alu heated printbed, and I attached it with a self-made power expander to an external 12v PSU.
Then I noticed that the heated bed wouldn’t turn of, so I resoldered the power expander twice, but it didn’t help.
I then noticed that the heat bed LED indicator is always on, I checked it with external LEDs and it turned out that
the heated bed output on the main board is always turned on…
I tried re-uploading the firmware but it didn’t help.
Have you got any solutions?
Thanks, but I don’t think that the thermistor is the problem,
When I plugged the thermistor in it was immediatly recognized and it showed a good temperature reading (the same as the thermistor in the hotend).
The problem is that the heated bed output is always on, no matter what.
When I stop the heated bed in repetier host, it still stays on…
When I unplug the thermistor, the heatbed still stays on…
When I reboot the 3d printer, the heatbed still stays on…
Did you make any changes to Marlin firmware the ‘Configuration.h’ file has a line that need
to be changed ? and the Start and End G–code in Cura
according to instructions in link ?
If it is well set, problem is that Power Expander or signal from Motherboard (bad conection)
I didn’t make any changes to the marlin firmware, because the thermistor I use is the same as in the hotend, so it was
immediatly recognized and gave a good temperature reading. I know that the connection to the power expander is also not the problem because the LED on the mainboard is always on, which indicates that the output of the heatbed on the mainboard is also always on…
I think you still have to make changes to the software because it’s about power management instead of a thermistor, try it can always reset the settings to the old one, try it according to the instructions
I made the changes to the firmware and the slicer, but it didn’t work.
I guess the problem is in the hardware and not in the software, since the firmware should be able to turn the heatbed on and off without making any changes to it…
you still have to make changes to the software because it’s about power management instead of a thermistor, try it can always reset the settings to the old one, try it according to the instructions 3d printing in delhi ncr gurgaon india
I also noticed that the DZ4 AND the DZ5 Zener diodes are ALSO missing, is this intended to be like this, or did something go really wrong in the manufacturing process?
This is too much to be fixed by myself so I’m going to enter a ticket at the velleman support site, and try to get a new motherboard…
If you look at the schematics DZ4 goes to the thermistor of Extruder 1
DZ5 goes to the thermistor of Extruder 2
DZ6 goes to the thermistor of the bed.
I checked my board they are not there.
I don’t think these are needed for proper operation of the board.
My heathed bed is properly switched on and off (via a relay) by the motherboard.
I dont recall that any software change was required.
Your connections might need checking.
Put a led with resistor on the motherboard connection to verify (and will be usefull later anyhow)
im using a heated bed without issues. you do need to set the right pins and behavour in the firmware.
also got rid of the old firmware version velleman provided and just went with marlin newest build when i did and reconfigured it.
I have checked everything carefully for incorrect connections but have not found anything if not in the software. So I wonder why the exit is always high.
Ive recently picked it up again so its been some 2 years since ive looked at the firmware or 3d printer ingeneral. But got something similair with the 2nd nozzel. ive set 2 extruders and 1 nozzle but now the 2nd nozzle heater pins are always on.
Another big issue ive had with the vertex is the numbering of the pins on the board vs the firmware, and if all else fails get a power-expander board and connect it to one of the pwm pins that are unused, which are again kind of a pain to find.
so lookup the technical datasheet and see if it helps some.