SMPS check
AC Should not be applied any time while adding resistors, or while unplugging connectors, as damage to the circuit PWB may occur.
AC Should not be applied any time while adding resistors, or while unplugging connectors, as damage to the circuit PWB may occur.
- The SMPS PWB "must" be producing Stby 5V, on pins 9,10,11 or 12.
- Must be generating ACD [AC detect] pin-18 check for 5V.
If none or any one among the said condition are not met, the SMPS PWB is defective, and must be replaced. There is no need to continue with any more test.
Unplug P800 on main PWB and P205,P205 to the inverters.
Add a 10K resistor between Pin-9,10,11 or 12 & Pin-19 (PWR). Apply AC. This will turn on the power supply.
- Check that 16V and 12V power supplies are turned ON, P201[16V pins 1&2] [12V pins 5&6]
- Check that the 24V [inverter B+] is turned ON on P 205 and P 204 pins 1-5.
If OK, the power supply is working well. Remove AC power, and re-insert plugs P204/P205 to the inverters.
If the above test is sucessfull. proceed:
Add a jumper wire between pin-20 (INV On/Off) to pin-19 (PWR)
Apply AC power. This simulates a Power On and Back light On command.
Observe the back lights should turn On. They will be dim.
If no back light activity. reconfirm 24V is being generated and output on P204/P205 connector pins 1-5. If not, unplug P204 OR P205 and recheck. If not, SMPS is defective. If yes, inverter is loading down the 24V line.
If all the above are normal, check the voltage on inverters.
