July 2010 LCD TV 47LE8500
63
LED Drive Signal and Troubleshooting InformationLED Drive Signal and Troubleshooting Information
Global Dimming (which affects every LED block at the same time) is accomplished by the P-DIM signal
arriving on CN1 pin 11 (Inv Main) and CN101 pin 11 (Inv Secondary). As P-DIM voltage goes up, all drive
signals will remain low longer. As P-DIM voltage goes down, all drive signals will remain high longer.
P-DIM has a range of 0.37V to 3.3V.
Local Dimming (which affects individual LED blocks) is also accomplished by these drive signals which are
manipulated by the Control Signals entering on CN11 Inv (Main) and CN103 Inv (Secondary).
100 IRE
3.68V p/p 120Hz
5 IRE
3.88V p/p 120Hz
Drive Signals being delivered to the LED Blocks V1 ~ V216
Note: If a particular block is exhibiting a dimmer level than the other or the overall brightness seems dim,
be sure to first check the customer’s Menu setting for Backlights. Raise the percentage and see if the
overall brightness returns to normal. If not,
1st Check the P-DIM level, it should rise with the percentage shown on screen. 0% = 0.37V to 100% = 3.3V.
Follow the P-DIM signal all the way to each Inverter.
2nd Turn off the set and unplug the connector to the Inverters coming from the Main board. If the brightness
returns to normal, the Main board is defective. If not, investigate all inverter voltages, if OK, use the
grounding of each V block procedure to test the panel’s backlight LEDs.
Leandro Palmeira
Downloaded From TV-Manual.com Manuals