X Command Waiting


I am in emotional roller-coaster right now. I have a feeling that the board is dead or about to die.

Just finished printing the parts for the fan. the part surrounding the extruder went smoothly. The part that attaches to the frame was harder. It kept destroyting the first three layers, so I decided to print those extra slow (50% of the initial speed). After the three layers, I gave 100% speed. The board’s temperature was going from 45C to 55C. That was different to the previous print outs. Why would it not stay at 50C?

Afterwards I started extensive testing with the printer settings and whether I need to replug the 15V power supply. Quite a few times it went with flying colors and then the error reappeared. I noticed that the LEDs were not as light as before (well, they got always dimmer as I plugged the 15V power, but this time a lot dimmer). So I took all the connections out and reattached only usb and power supply. Then I noticed that the part labeled 7805abd21rdnf40g (right to the 15V power supply) was getting rather hot (over 40-50C). If that chip is responsible for stabilizing voltage/current, I can imagine under what kind of load the poor guy had to operate. Cause the power supply is oscillating between 13 and 15.5 like crazy.

@Wrong_Way, do you think, you could measure the open circuit voltage of your power supply? Cause if I connect it to the machine, it is pretty stable, if I disconnect it, it starts fluctuating wildly :frowning:

I’ve tested the current flow. Without any load it takes between 0.5A to 1.0A. This is 15W. Uploaded the video:


Yes, it is the voltage regulator. I suppose it produces 5V (among other things):

I’ve measured the OCV on the ouput pin. It is 5V… then it drops to 4.2V. Then it drops to 0V. And then it repeats itself. The thermal protection must be kicking in. I am depressed beyond imagination.


I just checked mine.
It’s solid 15Vdc plugged or unplugged


Thanks, mate. This must be the cause. I need to contact velleman, I suppose. You know any good email address for that?




for support or repair please issue a ticket at http://support.velleman.eu

Best Regards,


I opened a ticket. And got the response:

Please return the product for inspection/repair/exchange to your Velleman distributor or directly to the Velleman Repair Department

Legen Heirweg 33
9890 Gavere

Make sure to include a detailed fault description, remove all add-ons and include proof of purchase if you want the item to qualify for treatment under warranty conditions.

US residents, please call (817) 284 77 85 to obtain an RMA#

so it seems that for velleman the ticket is closed. Who will take care of the shipment costs? Do I have any questions? Does not seem that velleman is interested in that. They just closed the ticket. Most probably it took like 5 minutes to read it and here we go. Issue resolved. What should I do in case I want to continue they say? Included problem description on detail level in later communications. Because the ticket is closed already.


Let’s give the benefit of the doubt for the Belgians:



I think the cause will be one of the controllers of the drives. I’ve rechecked all four of them one by one:

and tried to (recalibrate/)set the 0.55V for all of them (it is pretty hard to do so as turning just a slightly bit increases the voltage from 0.54 to 0.55 or from 0.55 to 0.56V. The current settings for three of the controllers is 0.55-0.56V except one of them, which is 0.53V. Turning the adjustable resistant (increasing the voltage) for that one over 0.53V shuts downs the circuit. I’ve been adjusting the resistors with all of the controllers in (compared adjustments, where only one is in, as the voltages drop quite a bit with all four in)

Interestingly enough, if I adjust them with only one in, the current that is pulled varies individually from one controller to the other. Two of the controllers pull 0.24A, one pulls 0.18 and the one that messes up the whole thing with voltages over 0.53V pulls 0.5A. If I put all of them in and with 3 of them at 0.55V and one of them at 0.53, the overall consumption is 0.9-0.7A at the beginning but slows slows down to 0.4-0.3A in a minute or two.

What does the voltage mean? Can it vary from one to the other (0.55-0.53)? Should all have the same (all have 5.0V or 5.1V, etc.)?

Additional comment on the smell. Does it smell a bit if you print? Cause in my case it does slightly. I always connected this to the cooking PLA, but the smell also appears even if I don’t attach anything to the CPU board. Anyone having similar experience? This must be the voltage regulator L78xx heating, right the chip? (L78XX is over 120C in my case.)

In those tests I have used an external adjustable power supply set at 15V