Well I have completed my 12VDC QMX. I have it connected to a current limited power supply set at about 25 mA at 9VDC (yes I'm paranoid). I have a power meter and dummy load on the BNC output. The LED backlight pot is at about 50%

I plugged in the USB cable BEFORE switching on the power supply and immediately Win10 gave my the dreaded USB Device not Recognized. When I switch on the Power supply no current is drawn and there is 9 VDC on the power connector on the PC board. Similarly a long push of the left encoder yields no current drawn. (This is a good thing -- hi!)

I have tried 3 USB cables. Two get no reaction from my PC and one gets the USB error message. None of the cables yield ANY reaction on a Linux PC?

I'm not sure what's happening? I assume that applying power to the QMX should cause it to enter and or display Update firmware. Is a long press of the left encoder required for that to be displayed? Is is displayed on the LED display or on the computer?

The "flaky-ness" of the USB cables has me leaning toward a USB cable problem some have encountered. I have successfully updated the firmware on my QLG2 but it uses a different USB cable. So, am I correct in assuming that -

• IF I have a faulty USB cable,
• the USB device will not be found,
• no bootloader will be installed,
• the backlight will stay off, and
• without firmware the QMX will draw no current?

Have I misinterpreted something. Some comments on this site suggest that the QMX will turn on (no LED display) and draw current (~150 mA) without a USB cable attached when the left encoder is given a long push??

Finally, the USB-C connector on the main PCB looks a little dicey! (Photo attached)

Thoughts appreciated. Thanks!
--
73, Rick
VE7TK

Website: