What would cause the Low state to go to -2 volts vdc? or to +2 volt vdc?

Most Low logic states are close to zero volts, but what faults would cause the logic low state for either TTL or CMOS to go to another voltage other then zero volts?

What are the Common failures that would cause the logic low state to be other then zero volts?

 

power supply fault. negative side of supply open to ground.

 

power supply fault. negative side of supply open to ground.

The Logic low would be at what voltage?

 

What are you using to measure the voltage?
If you are using an oscilloscope make sure your probe and scope input are both set to DC.

 

if the ground reference of the supply opens, what voltage do you measure to ground? I have had it happen with a + and - 15 volt supply, very strange readings.

 

if a pull down resistor is shorted or open, what would happen to the Low logic state?

When a logic IC chip gets damaged, the High logic state goes to 1.7 volts , why is that?

 

Hi again Billymayo, still using multiple personalities?

 

if a pull down resistor is shorted or open, what would happen to the Low logic state?

in order - (1) low (2) high (assumption - you have an inkling of how logic circuitry is intended to operate)

When a logic IC chip gets damaged, the High logic state goes to 1.7 volts , why is that?

apparently your not familiar with the rhetorical theorem?