A +5 V PCB power source that has been "pulled down" to a +3.4 V level may be due to:

Erratic or unexplained digital circuit activity is often due to _________.

Measurement of pulse width should be taken at a 50% mean of the:

The device that would best aid in open track detection is a(n) ________.

A check of all power supply voltages should be made during the ________ method of troubleshooting.