Is your VFD not powering up even with applied input voltage? It may be due to a fault at the charging resistor or SMPS output. The I/O board may also be at fault. 

First, check to see if the keypad is lit. If it does not then determine if the input voltage is running at normal levels. If it isn't, check your power supply. If the power supply is running normally survey the machine to see if the LED charge light turns on. If the charging light is working as it should investigate the charging circuit for abnormalities. 

If the LED lamp isn't turning on determine if the P1, P2 terminal block is available and if the Short Bar is aligned properly. If it isn't, tighten the short bar. If it is, check to see if the connector inside the inverter is tightened properly. If it isn't, make sure that is on tight. 

Below you will find other potential solutions for your VFD not powering up.