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Anthony_Infotech
Anthony_Infotech, Technician
Category: TV
Satisfied Customers: 13923
Experience:  20+ years experience TV expert (field and bench) 9 approved qualifications in TV-ELECTRONICS
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I have an LG 50PK550 plasma tv that has a problem with the

Customer Question

I have an LG 50PK550 plasma tv that has a problem with the picture not appearing but I can hear sound. In one instance the display managed to turn on but it was static noisy picture and I could still faintly see the menu and navigate it but after that time the display no longer turn on. Any help fixing or at least diagnosing the problem would be greatly appreciated.
Submitted: 1 year ago.
Category: TV
Expert:  Anthony_Infotech replied 1 year ago.
Hello my name is Anthony
Welcome
Thanks for the Question
Sorry you're having trouble hopefully I can help, the first check is press the menu button of the sets own remote control does the menu come up?
If not can you see any feint light at all on the display even in a darkened room and even for a second?this will indicate if the panel is primed or not
Anthony
Customer: replied 1 year ago.
Hi AnthonyThe menu does not appear and there is no feint light on the display.
Expert:  Anthony_Infotech replied 1 year ago.
OK its very likely the Y scan board is none operational however there is a procedure to follow to confirm that using a meter (volt/ohms/amps)to check the Vs or VSUS and the Va scan voltages on the power-board depending on the result of those checks moves the diagnosis on, if you think you can do this work let me know it will mean replacement of a board or boards.
Sorry its nothing easier.
A tech would charge around $280 for the work you can locate a approved tech in your area by using this web address www.tvrepairpros.com
Let me know if you can do this or need more info
A positive rating is appreciated thank you, ***** ***** be a rating bar of smileys or stars with this post please pick out a positive rating and click submit or finish thanks again, rating me positively is the only way I receive a proportion of the fee from the site, please note the question will remain open.
If for some reason you do not see the rating bar please let me know and let me know in that case if you are satisfied with my diagnosis or answer.
Regards
Anthony
Customer: replied 1 year ago.
on the power board the Vs reads 200V and Va is 60V
Expert:  Anthony_Infotech replied 1 year ago.
Hello
That sounds OK and this is WITH both scan boards connected you HAVE NOT disconnected them?
If so run the set for 15mins , switch the set off and feel the heatsinks on the scan boards left and right are they warm or cold?
Anthony
Customer: replied 1 year ago.
yes this is with both scan boards connected.Heatsinks on the Y board are warmed up (some of the heatsinks are warmer than others) and Z board they are cold.
Expert:  Anthony_Infotech replied 1 year ago.
And the logic board has the light blinking about once every second yes?
Has the set suffered a storm damage or any other outcome like that?
Anthony
Customer: replied 1 year ago.
the logic board blinks in this sequence, long blink,quick blink, pause, long blink,quick blink, long pause.Unfortunately I wasn't home at the time the display stopped working but we were bad storm for a couple weeks.
Expert:  Anthony_Infotech replied 1 year ago.
There is no short circuit on the power-board so usually if the scan boards fail they go short and take down the power-board, it could be a logic board issue as I suspect that blinking is not correct, its the thing I would replace next unfortunately in this situation your left swapping out boards to eliminate....there is no effective check for any board except when they go short (scan boards)...its a possibility too that the Z board or both are bad, storm damage is the usual culprit for this type of problem
Let me know which way you want to go with this
Anthony
Customer: replied 1 year ago.
if the control board is bad would it cause the z board to not function since it doesn't even get warm and does the blink pattern mean anything?
Expert:  Anthony_Infotech replied 1 year ago.
No there is no blink code but the blinking can become erratic or no blink at all the logic board controls the action of the scan boards and yes it could be the Z board or both there is no way of knowing you would need to swap boards in a workshop its usual to be able to do that you do not have that option without ordering boards, the thing is there is no short circuit the most common cause of scan board failure is a short circuit taking out the Vs and Va, one other thing carefully check the panel itself for any cracks
Anthony
Customer: replied 1 year ago.
The panel is definitely not cracked at one point it managed to display a static picture and I could faintly see the menu and move around but since that time it hasn't come back on.
Expert:  Anthony_Infotech replied 1 year ago.
Its as I have already explained your caught between a rock and a hard place with the swapping of boards even at workshop level we are left doing the same and its not just with plasma LCD are the same, you can get someway into checking then its just down to experience and the most suspicious board....I would change the logic board then the Z
The mainboard is working because you have the logic board doing something and you have sound
Anthony
Expert:  Anthony_Infotech replied 1 year ago.
If you wish to order the boards you will need the part-numbers found on the boards themselves then using those part-numbers www.shopjimmy.com or google the part-numbers thank you
If you need any more info please let me know
Regards
Anthony
Customer: replied 1 year ago.
After doing research I was hoping to get a some guidance on what specifically to test for like capacitors, diodes or transistors etc that I have seen others test/replace on various tv repair forums and youtube videos. Thanks for the help tho
Expert:  Anthony_Infotech replied 1 year ago.
No there is no way to do that, the boards do not lend themselves to component level repair its ALWAYS aboard replacement exercise even at workshop level 90% of the time, its because the boards are densley populated with electronics and even the soldering is not approachable if it was you would need very expensive solder/desolder equipment, I know you do not like what you are hearing but honestly this IS the way it is, there cant be a you-tube video for this otherwise you will not be asking the question...
I will help you but you must swap out the logic and maybe the Z sus
Anthony
Customer: replied 1 year ago.
I didn't mean youtube video for my specific tv but I've seen video on other tv brands/models being repaired this way on youtube channels like tampatec and even Shopjimmy's own youtube channel, there is just not much info on my tv that's why I asked here. Even shopjimmy.com sells kits to replace components that have failed, like this kit (again not my tv but just an example) http://www.shopjimmy.com/panasonic-txnsc1eduu-sc-board-component-repair-kit.htm. I do have soldering/desoldering equipment and I've fixed my amplifier and other audio equipment in the same manor with help from users on audio forums.
Expert:  Anthony_Infotech replied 1 year ago.
Yes I understand what you say but NOT in this instance, the Zsus is $32? the logic $24 why get involved with component repair when the boards are that cheap?and also NOT for every fault (as per what you say)
Sir you have asked a question I have replied with my answer(s) if you don't believe them you have the option of opting me out or I will opt out
Anthony