LG 42PQ30 Training Manual page 81

Control PWB Testing
Control PWB Testing
For quick PWB test.
(All PWB connectors
Disconnected).
Jump 5V from Power
Supply to IC201 Pin 1.
(Bottom Pin)
If the LED blinks,
Pretty much
guaranteed,
PWB is OK.
When the Television has a problem related to;
1) Shutdown caused by Main PWB
2) No Video (No Picture) Sound OK.
This can be checked by the following.
(1) Disconnect the Main PWB from all connectors. Apply AC power.
Since P813 is not connected to the SMPS, the set will come on.
Short the two pins on the Auto Test Pattern lands.
If there is a picture of cycling colors and patters, the Y-SUS, Y-Drive, Z-SUS, Power Supply, Control PWB,
X-Boards, TCPs and Panel are all OK.
Use the same test for problem (2)above to tell if the No Video is caused by the Main PWB or failed LVDS cable.
Preliminary Information 42PQ30
81
Confirm B+ to Control PWB
VS_DA
Control PWB Check
3V ~ 3.3V
(Note, this TP can also be
Used as an External Trigger
For scope when locking onto
the Y-Drive signal).
Quick observation
Of LED blinking
Tell if the Control
Board is running.