Power Supply Board Low Voltage Tests - LG 55LW5600 Troubleshooting Manual

Power Supply Board Low Voltage Test 1
AC Should not be applied at any time while adding jumpers or
While unplugging connectors as damage to the circuit Board While unplugging connectors as damage to the circuit Board
July occur.
a) When AC is applied, the SMPS "MUST" be producing
STBY 3.5V on pins 9, 10, 11 or 12 of P201.
If 3.5V Standby is not being generated, the SMPS is defective
and must be replaced. There is no need to continue with the
next test.
But, make sure AC is arriving at the connector SK101.
(b) Unplug P502 on the Main Board to make insertion of the Jumpers easier.
Use P502 Side to insert resistors
TEST 1:
(1) Add a jumper between (3.5V STBY) pin 7, 8, 9 or 10 and Pin 1 (PWR_ON).
Apply AC. This will turn on the power supply, relay will click.
a) Check that the 24V (25.02V) and 12V (12.08V) power supplies are turned on,
• P201 (12V pins 17, 19 and 21)
• P201 (24V pins 2, 3 and 4) • P201 (24V pins 2 3 and 4)
• P202 (56V pins 1 and 12) AND P203 (pins 1 and 13)
(2) Remove AC power
No Backlights during this test
54
SMPS TEST 1
Front pins on Front pins on
Connector are
Odd number
12V
12V
12V
STBY 3.5V
STBY 3.5V
24V
PWR_ON
Brown Wire
July 201 1 LCD TV
P201
23 24
21 22
19 20
17 18
15 16
13 14
11 12 11 12
STBY 3.5V
9 10
STBY 3.5V
7 8
5 6
3 4
24V
1 2
24V
Pin 1 is the
55LW56000