dmitri wrote:I don't understand...which other pin do I measure the voltage with pin 1, 8, 14, 19, and 20?
Measure voltages between USB socket ground pin and these pins.
Voltage measured between USB ground and pins 8, 14, and 19 is zero (0V) while with pin 1 and 20, voltage is +5V. These are the results whether the PIC is in the socket or not.