Backlight Test: (Extended Test)
CNL801
(LED Connector) 65"
1
1+
2
1-
3
2+
4
2-
5
3+
6
3-
7
4+
8
4-
9
5+
10
N.C
11
N.C
12
5-
VF CH1
Dim.
CH1
CNL801
(LED Connector)
43"/50"/55"
1
1+
2
1-
3
2+
4
2-
VF CH1
Dim.
CH1
CNL801
(LED Connector)
75" / 85"
1
1+
2
1-
3
2+
4
2-
5
3+
6
3-
7
4+
8
4-
9
5+
10
5-
11
6+
12
6-
VF CH1
VF CH2
Dim.
CH1
Dim.
CH2
CH1(+)
250Vdc
CH1(-)
60Vdc
[65” TV Example]
Panel BL Connector
:
Two Sets
of LED BL Strings seen in example (connected in series - if one fails both go off)
1. Activate Backlights Test
: Disconnect Lead Cable from Main to Power Supply.
9
Check TV Screen for active backlight LEDs.
2.
If NO BACKLIGHTS
9
Check CH1 (+) BL Supplies on SMPS (approx. 270Vdc for 65”)
9
Also Check CH2(+), CH3(+), CH4 (+)..etc. when included for larger TVs
→
If any missing replace SMPS Board.
→
If supplies are OK replace Panel.
3.
If BACKLIGHTS ON BUT PANEL SECTION(S) OFF
9
Locate CH1 (+) on SMPS and measure for approx. 250Vdc (65”)
9
Locate CH1 (– ) on SMPS and measure for approx. 60Vdc (65”)
→
If CH1 (+) is very low or missing replace SMPS Board.
→
If CH1 (+) is OK & CH1 (-) is near 0 Volts replace Panel.
9
Check CH2 (+) and CH2 (-) when included for Larger TVs
→
Repeat the same Test as with CH1
9
Continue to Check CH3, CH4, …, etc. when they are also included.
BACKLIGHT DIMMING PROBLEMS:
9
First check Option Byte Settings in Factory Mode. Wrong settings can create backlight errors.
1.
Go to
Menu
£
Picture
£
Expert Settings
£
Backlight
and vary level (0 – 50)
2.
If no backlight changes are observed, vary the level again:
9
Check
BLU_PWM
(pins 6 ) control voltages
CNM801
varies approx. 0.5V – 2.5Vdc
→
If it doesn’t vary voltage replace Main/T-CON Board.
→
If it varies and back lights won’t dim, replace SMPS.
4-10
4. Troubleshooting
