Electrical whizz needed :)

[ecat]

EStop is a good one to check as are the LEDs and actual voltages. Also check all limit and home switches.

It would be unlucky to have blown all four drivers but the lack of a second clunk does sound like a fundamental problem. I assume you have a multi meter? Set it to DC volts, 10v or 20v range if applicable and measure the voltage across the STEP inputs on the X axis driver, right up at the green connectors. It may read 0V or xxV (near 5V most likely), now with your other pair of hands use the pendant to jog along the X axis and see if the meter reading changes. Any change in voltage associated with the movement tells you that the step control signals are getting as far as the driver, no change in voltage tells you that the problem exists before the driver.