LG 60PC1D Training Presentation page 42

Remember to always check the resistance for possible shorts if you are missing a voltage
• With AC Power applied only, the AC/DC Supply will develop 20V and 160V at P8016A to the Standby Supply.
Failure to produce these voltages indicates a problem with either the AC/DC Supply Board or the AC Filter.
Check the AC Input at P801.
• The Standby Power Supply outputs 12 Volts used for AC Relay operation at connector P8015B and
5 Volts Standby and AC Detect at P801A and is sent to the Micro Processor circuit for Power On and Control Functions.
Failure of the 12 Volt Supply, 5 Volt Standby and AC Detect indicates a failure of the Standby Power Supply.
• The Micro Processor supplies a high to P-CTL Pin 2 of connector P801A causing the AC Relays to close on the
AC/DC Board and develops 110 Volt DC at P8017A which is applied to the PFC Board turning on the 380 Volt
PFC Supply and the 18 Volt Supply on the PFC Supply Board. These voltages are then used to develop the 19v, 12v,
6v, and 3.3v supplies. Failure of the Relays to close could be caused by a loss of "ON" Command from
the Micro Processor on the Main Board or a Standby circuit failure. Relay operation indicates an active processor
circuit and Standby Circuit. Check for approximately 110 volts at P8017A if missing suspect the AC/DC Board if
present and the 380 Volt and or the 18 Volt lines are missing suspect the PFC Supply.
Presence of the PFC and 18 Volt lines and no output would indicate a failure of the SMPS.
• The next step is to have the Micro Processor bring the unit into full power on mode, this is accomplished in 2 ways
by first bringing the VS ON ( Pin 5 ) of connector P801A high in order to develop the VS ( Pin1 ) and VA ( Pin 10 ) on
connector P8011, second bringing the POD ( Pin 7 ) of connector P801A high to develop the 5VDC at connector
P8012. Failure to develop VS, VA, and 5VDC, if the control lines are high, suspect the SMPS Board as the problem.
Make sure you remember to check each resistance load for possible shorts if the voltage was missing!
Plasma Display Panel Troubleshooting - 2007
60PC1D Power Supply
Power On Sequence
42
Troubleshooting