Lg 50pb690v-zc

[comptek]

Hi guys this one has me stumped i have checked theres no image, turns on and off with remote, report was pic went off but still had sound, i replaced all boards except for lower buffer boards, (the replacement boards were from a smashed screen tv same model etc), there is no activity on the led on the controller board, and i noticed that the red light in the digital out is not lighting either, 5v standby is there, i have checked VS = 207 VA = 55/4 va changes from 55 to 54v constantly panel states 207v and 55v i disconnect lower buffers and the 55v returns steady, but no 18v line present between y sus and z sus

many thanks

[comptek]

Re: Lg 50pb690v-zc

anyone please any ideas suggestions beside chucking it lol

[ReeceyBurger123]

Re: Lg 50pb690v-zc

Does the panel glow in a dark room Gaz ? Also checked it over for cracks etc ?

[martino]

Re: Lg 50pb690v-zc

there is no activity on the led on the controller board, and i noticed that the red light in the digital out is not lighting either

many thanks

That almost sounds like a missing voltage or one that gets suppressed by a short. The logic board gets its voltage from mainboard it looks like.
This happens with both mainboards?

disclaimer: I am NOT good with LG's lol,They always bite me before they surrender. I'm merely getting the discussion going for you to help get a more knowledgeable person in here

[comptek]

Re: Lg 50pb690v-zc

Does the panel glow in a dark room Gaz ? Also checked it over for cracks etc ?

no Glow and a crack maybe unlikely as they were watching it and it went off plus the screen is behind a glass panel if you know what i mean

[comptek]

Re: Lg 50pb690v-zc

That almost sounds like a missing voltage or one that gets suppressed by a short. The logic board gets its voltage from mainboard it looks like.
This happens with both mainboards?

disclaimer: I am NOT good with LG's lol,They always bite me before they surrender. I'm merely getting the discussion going for you to help get a more knowledgeable person in here

hi Martino, i have changed all boards exactly the same boards, though saying that they came from a smashed screen,when i replaced the lower buffer boards the led on the front was flashing which hadnt happened before so i removed the left hand one of the 3 and the led no longer flashes :/

[Hamie]

Re: Lg 50pb690v-zc

Any LED on the control board?

[comptek]

Re: Lg 50pb690v-zc

Any LED on the control board?

yes there is Hamie, but there is no activity at all no flashing not lighting at all
tried another main board from a smashed set but still the same

[comptek]

Re: Lg 50pb690v-zc

******** UPDATE ********

sorted it it was a burnt out cap between the yellow transformer and the nearest heatsink on the ysus cap was C205 checked fet and diode close by and they checked out ok
replaced it and now the set is working and got the 18v back on the z sus

thanks guys

[ReeceyBurger123]

Re: Lg 50pb690v-zc

Awesomeness

[martino]

Re: Lg 50pb690v-zc

******** UPDATE ********

sorted it it was a burnt out cap between the yellow transformer and the nearest heatsink on the ysus cap was C205 checked fet and diode close by and they checked out ok
replaced it and now the set is working and got the 18v back on the z sus

thanks guys

So was that on your old or new y board?

[comptek]

Re: Lg 50pb690v-zc

So was that on your old or new y board?

both Martino,
one the cap was blown and fet and diode was ok
one the cap was ok and the fet and diode were short
i could smell a faint burning smell

i think the tv with a smashed screen either went wrong and then he lost his temper with it and smashed it or the screen getting broken caused something that took the cap out