TCL 65S403 Blank Backlit Screen w/ sound ... voltage besides 12v missing at LVDS

[triplefour]

Blank Backlit Screen w/ sound verified via DVD on HDMi 3
no change to display when disconnect tcon
no change to display when disconnect panel cables (both sides, one at a time, etc-)
can faintly see a vertical dividing line splitting the panel even in half. super faint tho.
also can faintly see a black cloud in the center of the screen. a darker area.
color of screen is backlit black screen which basically looks gray
12v present at TCON fuse
other voltages on LVDS cable (TCON side) are missing. only see 2 pins with voltage .69v and .60v
values dont change when disconnecting panel cables or when there is no siganl present (unplug DVD from hdmi3)
Standby light continually flashes in the pattern 2 quick flashes, 1 second pause, repeat
tv has "speaking menus" enabled
suspect MB for not sending voltage to LVDS cable but cant rule out panel defect as well.
or maybe tv thinks im blind so why bother display picture???
any help is much appreciated!
thanks

[triplefour]

Re: TCL 65S403 Blank Backlit Screen w/ sound ... voltage besides 12v missing at LVDS

anyone have any tips? should i just assume the MB is bad since i dont see voltages (besides the 12v) going to TCON?

[tmhobadcap]

Have you tried checking on the backlight leds?
I have the same tv with a few leds failed. Then there is no picture on the screen but sound.

[tiki66]

Re: TCL 65S403 Blank Backlit Screen w/ sound ... voltage besides 12v missing at LVDS

anyone have any tips? should i just assume the MB is bad since i dont see voltages (besides the 12v) going to TCON?

MB only sends 12V to t-con and then t-con "creates" other voltages. Check for HAVDD, AVDD, VGL, VGH and other voltages on t-con, first with one side of screen connected then with other side of the screen connected. Are there any?