Ok, so when I plug usb cable, computer founds printer from com 6
lights near usb plug turns on.
then if I connect 15V power from transformer, some leds just blinks and turns off.
there is still 0.850V on motor controls, but i trimmed them to 0.435-0.444 (couldn’t get any more precise, but don’t think that matters), but problem is that I cant control board, it doesn’t seem to connect and there only reads something like xx instruction is waiting in queue
I did try earlier to start without stepper motors, heaters and thermistor (didn’t bother to remove x,y and zstops, they should be short/open anyway, shouldn’t matter anything.
video about powering:
youtube.com/watch?v=k4IlKw0pJeU
because all lights go off, I feel that is not computer related, normally all devices has some lights 
If you reset the controller board manually by pushing the button, the “waiting” instructions will clear out of the queue. You will notice that the “connected” icon in Repetier shows you are connected, but that there are commands waiting.
There are two solutions:
- Reset the controller manually.
- Change the Repetier printer option defaults to “disable reset on connect”.
You actually are connected. There are just unexecuted commands in the queue.
Oh, I see. if press reset button, i’ll get “error:system.io.ports.serialerrorreceivedeventargs” so next im going to try another comp and if doesnt do anything, msg on “Computer related problems” sub forums 
edit, after selecting right speed, no errors
Hi,
In your video you clicked on connect then plugged the power into the printer.
It is normal for the LEDs to be on before you apply power to the printer.
Try powering the printer then clicking on connect.
Make sure your baud rate is set to 250,000 and Rest on Connect is set to Disabled.
