lg 50pg3000 sound no pic

[daphney]

i have read the posts on this model on here & found useful in trying to trace problem but no joy i took some voltages
va 60.6 vs 193.6 vy 46 vsc 46 & on ysus board theres 2 125v 10a fuses
fs701 60v fs 202 5v i have tried with top or bottom buffer disconnected & no dif still no pic im not sure wat vy & vsc should be
is it possible to run auto gen to see if panel is fine ?if so how ?thnx
also after 30mins on heatsinks on ysus still cold zsus 1s are warmer
any ideas would be greatly recieved
thnx as always for your help

[sordids999]

Re: lg 50pg3000 sound no pic

https://www.badcaps.net/forum/showthread.php?t=18892

[daphney]

Re: lg 50pg3000 sound no pic

thnx i read that earlier. wondered if there was anything else i could test before going threw ysus board
thnx as always

[tom66]

Re: lg 50pg3000 sound no pic

Disconnect Y-buffers, if Vsc/-Vy return the Y-sus is ok, buffers short, very common on this model. No way AFAIK to tell if panel ok as top buffer usually goes, won't work with bottom buffer only.

[daphney]

Re: lg 50pg3000 sound no pic

y buffers ? as in 2 boards on left of ysus that slot in? if so i unplugged from slots from ysus & voltages are now vy 85.6 vsc 25.6
thnx as always

[tom66]

Re: lg 50pg3000 sound no pic

Compare to panel sticker. -Vy is negative, Vsc about 120~150V.
Measure ACROSS resistors on Y-sustain.

[daphney]

Re: lg 50pg3000 sound no pic

done on resistors black on _ red on + of each resistor & vy 195.3 vsc 135.1 on panel sticker under va vs voltages is n/a -195 /135 but the 195.3 on meter is + is that correct?
thnx as alaways
sorry if im being dumb

[tom66]

Re: lg 50pg3000 sound no pic

That is fine, you have a shorted buffer board ,probably the top one

http://www.ebay.co.uk/itm/EAX5005080...item25987d4c73

[daphney]

Re: lg 50pg3000 sound no pic

thank you very much for all your help bottom of screen works now
u guys are great much appreciated

[daphney]

Re: lg 50pg3000 sound no pic

i have another of this model & as i fixed with top buffer before thought b easy
hmm however i purchased another top buffer as it had lines on screen but was same when turn tv on it shows wats in pics then screen goes off within 5seconds i never get any colour with top or bottom buffers removed individually does same & shows same with half screen blank obviously
any ideas or is panel dead?
thnx as always

ps;hope pics clear enuff for you to see wat i mean

[daphney]

Re: lg 50pg3000 sound no pic

took voltages va 65 vs193 vy vsc & vzd all 99 if earth on chassis 0.01 across resistor screen is black then doesnt stay on long enuff to check when like in pics
thnx for help as always

[ReeceyBurger123]

Re: lg 50pg3000 sound no pic

I have one with lines on screen with colours rest blank, found top buffer to be shorted and a bubble burnt into it seems very common with thse sets.

[daphney]

Re: lg 50pg3000 sound no pic

i dont see any colour sound is fine get wat pics show for 5secs mayb2 lol gott b quick to take pics replaced top buffer with another no diff am thinkin mayb tcon coz of voltages but i not sure????????????