SMPS may not turn because of these reasons.
1. SMPS is not getting a power supply.
2. SMPS is spoilt
3. SMPS is detecting a short in the machine circuit and is auto shutting down.
Troubleshooting:
Note: Checking the SMPS input when the machine is on is a risky task. You can get an electric shock with fatal outcomes. So please do it at your own responsibility.
1. SMPS is not getting a power supply: Take a multimeter and check the power input to the SMPS. The input Voltage should be 220 Volts.
If the input is correct, check the output.
Turn on the power switch and check the voltage. Voltage should be 220 Volts. If the SMPS is not getting input, then the power supply/Wiring should be checked.
2. SMPS is not outputting power: If input is correct, check the SMPS Output by keeping the multimeter probe at the output.
Note: Take a picture of the wiring before removing wires, so you will have a reference while reconnecting wires.
Check the output of the SMPS.
If SMPS is not outputting power even after getting input, then remove all the output wires and check.
After removing all wires, check the output. If the output is 24 Volts after removing the output wires, then a wiring short is the issue. Or else SMPS is damaged. If SMPS is damaged, replace it or otherwise, you need to find the short in the machine.
Finding short in the machine.
