phillips 32pfl5522d/05 no video backlight working

[shaunbt123]

hi there
can someone give me some advice regarding this set ,the problem was lines down the screen,so i changed the tcon board and now i get nothing at all,not even the menu screen.i have tried re-seating the ribbon cables from the tcon but no luck.
when i power it up i can see the backlight is working,i have also connected this set to a second set using scart lead and the picture is fine through the second set,i have also measured the voltage at both sides of tcon fuse which is 11.97v.
i have tested all caps on power supply board and esr is fine on all of them.
the tcon board is a sharp tw10794v-0
thank you.

[selldoor]

Re: phillips 32pfl5522d/05 no video backlight working

wrong tcon? any fuses on it? try the old one back in?

[shaunbt123]

Re: phillips 32pfl5522d/05 no video backlight working

all fuses on both tcon boards ok, i put the old tcon back in but all i have is backlight and no images on screen.
thanks.

[MrTrollsten]

Re: phillips 32pfl5522d/05 no video backlight working

I had an lg tv from around 2008 with a very similar problem, the backlight would turn on and it would play sound but it would either display no picture at all or picture with green lines on the right side. It ended up being a bad solder joint on a bga chip on the sub-tcon board. What i did to find the problem was to warm up each board that had a bga chip individually with a hairdryer and watch the display. This may not be your issue, but is worth a shot.

[selldoor]

Re: phillips 32pfl5522d/05 no video backlight working

Is there a voltage on the tcon fuse? - Is there a fuse at the other end of the cable on the main board. Try another lvds cable - check that one for shorts/opens

[shaunbt123]

Re: phillips 32pfl5522d/05 no video backlight working

yes there is 11.97 volts on both sides of tcon fuse.i dont have a lvds cable so cant try that.ill have a look to see if theres a fuse on mainboard.
thanks.


cannot see any fuse on mainboard.

[shaunbt123]

Re: phillips 32pfl5522d/05 no video backlight working

anyone else have any ideas on this one please.

[budm]

Re: phillips 32pfl5522d/05 no video backlight working

Try having the ribbon cable between the T-CON and the LCD panel connected one at a time to see what happen.

[shaunbt123]

Re: phillips 32pfl5522d/05 no video backlight working

thanks budm.
i have tried having one cable at a time plugged in,but the screen stays the same,, backlight on and all the screen looks the same.i have tried reseating the ribbon cables but no luck,i also know i have 11.97v at both sides of the tcon fuse.

[budm]

Re: phillips 32pfl5522d/05 no video backlight working

OK, you will need the scope to see if the main board is sending the LVDS signals tot eh T-CON or not. I will lean toward bad T-CON.
Which one of these is your board?
http://www.shopjimmy.com/catalogsear.../?q=tw10794v-0

[shaunbt123]

Re: phillips 32pfl5522d/05 no video backlight working

hi again budm
it looks like the first one at the top of the page.thank you.
ps i have swapped the tcon for another one but its just the same.

[budm]

Re: phillips 32pfl5522d/05 no video backlight working

OK, check the DC voltage of the legs (pads) of the inductors L1, L2, L4 located at the left side of the board.

[shaunbt123]

Re: phillips 32pfl5522d/05 no video backlight working

as soon as i have time i will check those voltages and get back to you with the results .thanks

[shaunbt123]

Re: phillips 32pfl5522d/05 no video backlight working

hi again
just to let you know i have tried again with the other tcon board i bought, and i now have sort of a picture except a blue band running from top to bottom in the centre of screen and the tv now goes off after about 10 seconds and comes back on by itself.this one is puzzling me now.