Power Supply Trouble shooting

                  Power Supply


            SMS functional I's Model 

1) TL 494
2) LM 339

   Pin 3- feed back error
   pin 7 - GND ( grand)
   pin 14 - verification


# Power Supply Trouble Shooting
 1) system doesn't start
 - check the internal connections such as pin 20/24 power connector to board.
 - check the power supply unit (facing working or not)
 - Check for any short circuit SMPS board
 - Check all capacitors resistance, dodos and filters in power supply board.

# Power supply
 _ power supply doesn't work it produce large sound.
 - Shutdown the system and clean the dirt form the fan if it exits.
 - If problem is not solved then replace the fan.