LG 50PS80 Training Manual page 46

Using two 100 Watt light bulbs, attach one end to Vs and the other end to ground. Apply AC to SC101. If the light bulbs
turn on and VS is the correct voltage, allow the SMPS to run for several minutes to be sure it will operate under load. If
this test is successful and all other voltages are generated, you can be fairly assured the power supply is OK.
Note: To be 100% sure, you would need to read the current handling capabilities of each power supply listed on the silk
screen on the SMPS and place each supply voltage under the appropriate load.
4 5 8
or or
P811
Gnd
10) M5V
Vs
1 2
Pins or
P811
Check Pins 1 or 2
for Vs voltage
Note: This SMPS will run without a load, however if the Vs is not loaded,
the 17V will pulsate up and down.
It is always best to test the SMPS under a load using the 2 light bulbs.
50PS80 SMPS STATIC TEST UNDER LOAD
50PS80 SMPS STATIC TEST UNDER LOAD
9) M5V
8) Gnd
7) VA
6) VA
5) Gnd
4) Gnd
3) NC
2) VS
1) VS
10) M5V
9) M5V
8) Gnd
7) VA
6) VA
5) Gnd
4) Gnd
3) NC
2) VS
1) VS
T301
SC101
46
P812
Check Pins 6 or 7
for Va voltage
Provided the Power Button is
closed, any time AC is applied to
the SMPS, STBY 5V and AC DET
P812
should be present.
P813
If AC Det is missing,
the TV will not come on. It will
completely shut down Main
board.
P813
1,2,3,4) M5V
Check Pins 1~4 for
5,6,7,8) Gnd
M5V
P814
Check Pins 11 or 23 for
5V SBY
IC701
Check Pin 18 for
AC Det (5V)
P814
23
Check Pin 9,10,12 for
1
(+5V)
2
24
Check Pins 1 or 2 for
17V
Check Pins 5 or 6 for
12V