Vertex k8400 heated bed output always on?

The Marlin firmware the ‘Configuration.h’ file has a line that need
to be changed for the type of thermistor used

dl.dropbox.com/s/gsx5zu130azuno … 3.pdf?dl=0

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…

Alfredias

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

k8xxx-3dprinters.crimed.be/w … heated_bed

Here is topic:
viewtopic.php?f=64&t=14714

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…

That it is probably a power expander

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 am just wondering if it is intended behaviour that the heatbed output on the motherboard is always on…

I just noticed that a little Zener diode with the number dZ6 is missing from the mainboard, I will probably try to replace this myself…

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)

I already did that, and the LED which I attached is always turned on by the motherboard.

Hi mate
Have you been able to solve it? I have the same problem.
If I succeeded, can I ask how?
regards

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.

from firmware ive gotten:
#if MOTHERBOARD == 77
#define HEATER_0_PIN 10 //E0
#define HEATER_1_PIN 11 //E1
#define HEATER_2_PIN 6 //BED
#endif

#define TEMP_0_PIN 13 // ANALOG NUMBERING
#define TEMP_1_PIN 15 // ANALOG NUMBERING
#define TEMP_2_PIN -1 // ANALOG NUMBERING
#define HEATER_BED_PIN 9 // BED
#define TEMP_BED_PIN 14 // ANALOG NUMBERING

and this is working for me and hence neverlooked at again.

Dear, I have checked this in my firmware but this is the same as what you have prescribed so I think it cannot be. Is there anything else I can check?

if you got a power expander unit or something similair then use another triggering pin. appart from that im not sure what could cause it.