LG 42LH50 BACKLIGHT - EEFL BACKLIGHT DETAILS
This set have [EEFL] backlight lamps instead of [CCFL] lamps.
CCFL => Cold Cathode Fluorescent Lamp [Complicated structure]EEFL => External Electrode Fluorescent Lamp (Simple structure; Low price)
EEFL contacts [bulb design]
For CCFL, Hg gas is consumed mainly near the internal cathode.
For EEFL, longer life time is expected because there is no internal electrode consuming Hg gas.
BACKLIGHT PWB LAYOUT.
SMPS PWB
POWER SUPPLY BACK LIGHT DRIVE SIGNAL EFFECTS
Backlights will attempt to fire 4 times. During these attempts, the
error line will change from 5V ot 0V. [0V] when lamp tries to fire or
is lit. [5V] when the lamps are not lit. After 4 attempts, if the
Error Out line returns to 5V, this tells the Micro to turn the set OFF.
POWER SUPPLY CONNECTOR P201 VOLTAGE & DIODE CHECK
P201 Odd "SMPS" to P2400 "Main PWB
Pin
|
Label
|
Standby
|
Run
|
Diode check
|
23
|
nc
|
nc
|
nc
|
Nc
|
21
|
A.DIM
|
0V
|
1.75V
|
OPEN
|
19
|
NC
|
NC
|
NC
|
NC
|
17
|
24V
|
0V
|
21.4V
|
0.81V
|
15
|
GND
|
GND
|
GND
|
GND
|
13
|
12V
|
0V
|
12.3V
|
1.3V
|
11
|
GND
|
GND
|
GND
|
GND
|
9
|
5V
|
5.06V
|
5.06V
|
2.85V
|
7
|
5V
|
5.06V
|
5.06
|
2.85V
|
5
|
GND
|
GND
|
GND
|
GND
|
3
|
GND
|
GND
|
GND
|
GND
|
1
|
NC
|
NC
|
NC
|
NC
|
P201 Even SMPS to P2400 Main PWB.
Pin
|
Label
|
Standby
|
Run
|
Diode check
|
24
|
2PDIM
|
0V
|
3.3V
|
OPEN
|
22
|
ERR OUT
|
0V
|
0V
|
OPEN
|
20
|
INV ON
|
0V
|
4.5V
|
2.25V
|
18
|
24V
|
0V
|
21.4V
|
0.81V
|
16
|
GND
|
GND
|
GND
|
GND
|
14
|
12V
|
0V
|
12.3V
|
1.2V
|
12
|
GND
|
GND
|
GND
|
GND
|
10
|
5V
|
5.06V
|
5.06V
|
2.85V
|
8
|
5V
|
5.06V
|
5/06V
|
2.85V
|
6
|
GND
|
GND
|
GND
|
GND
|
4
|
GND
|
GND
|
GND
|
GND
|
2
|
PWR-ON
|
0V
|
4.5V
|
1.19V
|