Please select one of the following items to troubleshoot: Egt single, duals, triples and quads.
Do not apply voltage across the meter connections for testing, these are designed for working only with a millivolt source.
You can test the gauge to see if it is functional using an ohmmeter.
With the leads disconnected from the thermocouple, connect the meter to the ohmmeter.
It will read approximately 8.5 to 20 ohms depending on egt scale and calibration. you will see the pointer on the cht gauge move.
Ohmmeter varity, type, make and model will drive the cht pointer up the scale differently.
This is just a funtional check not a calibration check.