Board no good?

I don’t even know where to start. I methodically went through the directions and built the k8200 after about 40 hours I was done over the last 4 months. I downloaded the software and followed the directions to the letter. Plugged it in and nothing worked. I have been reading this forum and I don’t seem to be along.

  1. I got the following at the command line.
    " Firmware_name: Marlin VI; sprinter/grbl mashup for gen 6 firmware : 8200.com/Protocol_version1.0 machine_Type:k8200 Extrude_count:1"
    Close to what the manual says but not exactly.
    nothing works except the fan. A similar post by Miguel-8200 dated 11/27/14 stated he had the same problem. I was advised to him that the motor controllers be set to .55 volt instead of .425v as instructed in the manual. (the first extruder trimmer was easy but all the rest were almost impossible to adjustment ridiculously small). I went through them again and adjust all to about .5. The last one was easy but all the others were extremely difficult and the last one I couldn’t get over .38V. If I moved it clockwise or counterclockwise it went to 0v. That is when it moved at all. i plugged the computer back in and tried to connect it and the software would disconnect after and few seconds. The green led in the upper right hand corner no longer lights. The red and green light by the power connector are on. I re-checked the voltage and all are now .12v and the bottom (x motor) is still .38v.
    So now nothing is working. Is the board fried?
  2. I checked the resistance of therm 1 and 2 at the board connector. (almost impossible to do with only 2 hands) and got no reading. I checked the bed at the edge of the bed where the ribbon connects and got 65k ohms. I know the thermistor on the extruder was OK when I installed it. Can’t get a reading now.
    I don’t know where to even start to make this thing work.

Sounds like you have one (or more) serious wirig issues.

Try disconnecting all connectors except usb and power and look if it connects.
Then plug the connectors back one at a time to find out the possible troublemaker.

Since the 2 LEDs by the power connector are that say you are not getting 15 volts from the power supply.
You should check it at the blue connector.
The green LED in the middle of the board will blink a few times as the controller boots up and then go off.

hi,

Try powering down and removing a stepper motor driver (note the up direction/orientation) and carefully adjust the pot with a good fitting micro screw driver. Only turn the trimmer pot a couple of degrees MAX and use a magnifying glass so you can see it turn where a clockwise turn increases the ref. voltage. Insert the driver chip again, power up and check the ref voltage it should have increased. I found it easier to adjust them that way. They are extremely difficult to adjust.

Which version of the Repetier-Host software did you install? From the manual control tab in the software when you tried to test (say) move X by 10mm did the commands stack up and not get processed/executed?

I had installed 0.96 prior to getting the printer (I’m using win81) and couldn’t get it to work straight away with the
commands just stacking up. I removed the software via add/remove programs.

I then went back to the manual (k8200.eu/manual/printing/?c=002):

Download the virtual com drivers:
ftdichip.com/Drivers/VCP.htm
v2.12.00

Then I downloaded 0.84 Repetier-Host so that dialogs in the manual (chapter 2) made a lot more sense and I got the correct firmware status line as per the manual when pressing connect. (The win 7 dialogs in the manual are same for win81)

I had to update sli3er separately to solve a problem but nothing to with the build or communication side and just getting it to the working stage.

let us know how you get on,

Finally getting back into this. I am getting 15.4V at the blue terminal. The green LED by the lower right hand corner of the biggest chip on the board flashes twice and goes out when I plug in the USB. The device manager does not list a COM for the computer but shows COM 4 when I plug in the USB. The Printer settings in the Repetier software (ver .84) is set to port com 4.
I set, again all of the trimmers to between .5 and .55 volts. When I connect via the software, a red and green LED just behind the USB connector flash, in unison about once per second.
When I enter the command to move the Z 10 mm, I get the message:
“Printer stopped due to errors. Fix the errors and use M999 to restart (Temperature is reset. Set it after restart)”
OK what are the errors and what in M999?

dont know if it makes a difference but i plug in the usb first and then turn on power to the printer.

with 0.84 you get the dialogs as per the manual.
k8200.eu/manual/printing/?c=002

From the printer settings in the software you swapped baud rate to 250000?

did you get the correct firmware status when pressing connect?

sorry not sure about error messages

Tried it your way, connected the computer and USB first and then plugged in the printer. Same results. I get the message:
“FIRMWARE_NAME:Marlin VI; sprinter/grbl mashup for gen 6 FIRMWARE_URL: k8200.com/ PROTOCOL_version:1.0 Machine_type:k8200 extruder_count:1” I believe that is correct or was at least what I had before. Getting the same error message as before.

hi,

sorry haven’t had that particular error msg so just guessing.

assuming connection/communication is working. is the temperature for the extruder and bed reporting room temp.
(you can see the temp under the manual control tab)
with therm 1 and 2 plugs removed at the controller board is the temp reported at 0 deg?

You mention in the first post at not being able to measure the resistance of the extruder ntc. Perhaps if it is damaged then
it would tally with your error msg rather than the board being at fault.

viewtopic.php?f=49&p=54468#p54468

here’s more info

looks like you can swap the therm sensors to if it’s a board problem or ntc/wiring problem

Does the extruder and the bed report room temp when you connect to the printer?
If not unplug the one that is not reporting the correct temp
Therm 1 Extruder Therm 2 Bed
When unplugged it should read 0C
If it does read 0C check the wiring or thermistor.
You can check the resistance at the plug wires should be 100K at room temp
If it does not change it may be the board

OK looked at the link provided. I switched the extruder and bed temp sensors and got a reading from the extuder that is room temp (20.5c) when I put my finger on the extruder the temp went up. When I switched the bed shows 20.5 c and the extruder 738.8 c.
So I have a problem with the bed sensor. when I measure across the resistor I get a reading of 36.4. When I reverse the probes I get no reading. I thought this is a resistor, not a diode. When I set the meter to diode I get a reading of 640 in one direction and no reading in the other. When I put the probes on the end of the bed where the ribbon cable is connected, I get the same results. No reading in one direction and 640 in the other. When I was building the bed I did test the thermistor and got a reading I should have, according to the directions. I don’t remember exactly what that was suppose to be.
I tried reversing the connector of therm 2 at the board and nothing changed.
So now what? Should I try to get a new thermistor?

its pretty difficult soldering that surface mount ntc 100k - might just be a bad joint

worth buying a couple of spare ntc’s for both the extruder and bed - they’re not a bad price.

with the bed therm disconnected do you still get an error on connection. hopefully you can proceed on checking the motor directions, homing switches, fine tuning the belt tracking, z axis screw wobble etc

I got the Z axis to work. None of the others do. I swapped out the y and x to the Z and got those to work driving the Z manual control. So the wiring is fine as far as motor control goes. So it’s most likely the motherboard, Right? I got the extruder to heat and the fan to come on.

Hi,

SOunds like the USB and communication is up and running.

(Powered down) You could take a working stepper motor driver chip say the z driver chip and move it to x - if this works then it’s not the controller board but a problem with the stepper motor drivers.

It could be the stepper motor drivers voltage set low or the belts are badly tracked. Easy finger push for both x and y. belt doesn’t track heavily either way and sounds smooth then it’s not the belts.

Sounds like 2 drivers are working e and z. CHeck the volatge ref on the other 2 (or all 4) and try to adjust to 0.5V ish. It’s nearly impossible without a magnifying glass. You don’t have to do live like the manual says as long as you can see the cross turn 1/2 or 1 degree under the magnifying glass (clockwise increases the voltage) Power up and re check the the reference voltage.

Please see my post from 1/10 6:24 PM. X and Y work fine when plugged into the Z controller. Extruder works OK when I plug it in to the Z. So wiring is fine. I did not test the extruder controller by itself. Voltage on all controllers is .5v. So it would seem the controller board is FUBR. I looked at Velleman’s parts sight and I can find the board thermistor I need but no link to purchase them or is there a cost. I could find them elsewhere I know. Where can I buy a new controller board? It seems to just plug into the motherboard. Is there someone from Velleman monitor this forum and can answer this? Is it under warranty? Should be.
I also read somewhere on this forum that the extra thermistor supplied for the extruder can be used on the board in place of the surface mount NTC.

sales@velleman.eu

try Velleman first

Rapid Online

rapidonline.com/tools-equipm … ter-544764

I don’t see the bed thermistor but they could prob. help

Never used them but parts are cheap:
open-electronics.org/3drag-3d-printer/
store.open-electronics.org/inde … ccessories
reprappro.com/product-category/components/

I used the spare hotend thermistor on my heatbed as my smd thermistor broke too.

Works nice, just make sure it closely touches the heatbed for proper readings.