Hello all - I have built the 'EM84 USB Magic Eye' CPU load monitor circuit as published in January's issue.
The tube indicator bars glow dimmly, accompanied by a slight whistle from the transformer. The HT is 216V, but the heater voltage is very low indeed.
I read that the heater supply voltage / current is PWM controlled by the PC software, and this is where my problems start.......
When the monitor is plugged into a USB port, 'Device not recognised' appears - it does not even ask for a driver. I've downloaded the AVR309.zip file from the ATMEL website and have the nessecary drivers, but don't know where to begin installing the AVR software ??
Any help would be greatly appreceiated
Many thanks, Richard