Samsung UN J5500AF Series - Page 29

SMPS / Backlight Test
CM803
CNL802
230Vdc
A
3 LED Strings Control
Fixed Supply
LED Pins Min B/L Max B/L Full B/L Test
Panel Con.
Removed
Sample
2- open
3- 130Vdc 95Vdc 88Vdc 0 0
3+ 174Vdc 151Vdc 144Vdc 0 0
2- 174Vdc 151Vdc 144Vdc 0 Opened
2+ 218Vdc 207Vdc 200Vdc 0 257Vdc
1- 218Vdc 207Vdc 200Vdc 0 257Vdc
1+ 241Vdc 235Vdc 230Vdc 275Vdc 279Vdc
A
230Vdc (panel size dependent) BL Supply measured at diode Stripe(cathode). This will raise to approx 280Vdc
with an open string of LEDs.
Simplied BACKLIGHTS Test
1 Activate Backlights – Disconnect Lead Cable from Main to Power Supply.
2 Measure BL Supply voltage at 1+ or at the supply diode cathode (stripe).
3
Remove Panel connector and measure again to compare.
4
If voltage is high and stays the same high reading a string of Panel LEDs are open. Replace the Panel.
If the voltage is low and remains low the SMPS is defective.
4-8
4. Troubleshooting