Re: LG 50PA5500 no picture
OK. I'll check. hopefully it is the power supply.
OK. I'll check. hopefully it is the power supply.
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Re: LG 50PA5500 no picture
should i be using the remote to turn the tv on or does it even matter? I saw some videos of people using remotes to turn the tv on instead of the buttons.Comment
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Re: LG 50PA5500 no picture
It doesn't matter, just as long as the TV is "on" i.e. power light changes and it produces sound (if connected to the correct input)Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: LG 50PA5500 no picture
Just a thought...could a bad solder job on that c802 have played a factor in my tv not fully powering up?Comment
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Re: LG 50PA5500 no picture
Before jumping to conclusions check voltages first.
it's much faster and you can rule out faults straight away with just a few checks.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: LG 50PA5500 no picture
Well, i think i ruined the main logic board while checking the power supply! I was checking the va on the power supply when i heard a pop. Then the tv started clicking and smoke came from what looks like the main logic board because there use to be a green light flashing then the tv shut off. Then i powered the tv on again and the green light doesn't flash at all. Cant get a reading from the zbias and when i check the y sus it reads -55 when it should be -190. Now after 20 minutes or so, the tv automatically shuts off!Comment
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Re: LG 50PA5500 no picture
More likely you killed the panel, the logic board has no connection to Vs/Va except through the address buffers. Ah well, good lesson, be more careful next time.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: LG 50PA5500 no picture
How did i kill the panel? What are the address buffers?Comment
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Re: LG 50PA5500 no picture
The address buffers run along the bottom of the panel and they are connected to the control board. I would suspect the panel to be damaged as that is the only way testing Va could cause failure of the control board (perhaps via having the meter on the wrong range, like on mA instead of V.)Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: LG 50PA5500 no picture
This my tv that board right under the psu is the board im talking about. It use to flash green,now it doesn't.Attached Filesif you find these attachements useful please consider making a small donation to the site
Last edited by graveboy81; 05-16-2015, 07:16 AM.Comment
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Re: LG 50PA5500 no picture
I had it on V the whole time. I don't know tom66, i refuse to believe that panel is shot because of that board going out. Changing that board has to be done because it has ribbons that run to the y and z -sus and logic board.Last edited by graveboy81; 05-16-2015, 07:24 AM.Comment
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Re: LG 50PA5500 no picture
You can try installing a new control board then and see. It's just worrying me that you have shorted or tested something wrong and caused some damaged. I can't see how that board would go "bang" any other way. Could your probe have slipped while testing?Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: LG 50PA5500 no picture
The pin close to the va is this 5v pin. It was strange to me too. Before the va problem, I may have to change the y -sus too because after i plugged the upper buffer board back up, i plugged in the power coard and heard a small pop where the y-sus and upper board meet.Comment
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Re: LG 50PA5500 no picture
If Va and 5V is shorted, wow, that would kill so many parts. Va is 55V. 5V is... well, 5V. The panel, Y-sus, Z-sus, control and possibly main board would all be destroyed. I hope that is not the case, but it is the only explanation right now.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: LG 50PA5500 no picture
Gotta agree with Tom... If you shorted the Va to 5v you have really fried the set!
IF that is what happened I would cut your lossesComment
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Re: LG 50PA5500 no picture
Oh dear.
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Re: LG 50PA5500 no picture
But i still get a correct voltage reading from the va and 5v.
This is where the smoke came main logic control board. It has a small chip at what looks to be IC252.Attached Filesif you find these attachements useful please consider making a small donation to the site
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Re: LG 50PA5500 no picture
Power supplies are pretty tolerant - of all things that would survive that abuse that is more likely than anything.
I would say that if you want to try a new control board go for it, but the only thing that could cause that IC to burn from testing, AFAIK, is a short from Va or Vs to 5V.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: LG 50PA5500 no picture
Afaik?Comment
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Re: LG 50PA5500 no picture
"As far as I know"Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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LG42PC3D -UD originally with green lamp but no display or audio.
Owner says was working, then went 'pop'.
All 5V caps bulging. replaced.
All PSU output voltages within spec but -Vy is low on YSUS.
One of three parallel fets between SUS_OUT and SUS_DN is zenering,
eventually shorts DG. Replaced all 3 - -Vy now OK.
Y scan buffer test point does not follow YSUS output below -50V
Note: This unit seems to expect YSUS output to park at -Vy in between
drive signal pattern periods. A replacement drive signal board confirms this....11-18-2021, 11:49 AM -
All left and right refers to looking from rear of TV (or looking from front with TV upside down)- TV came with vertical bars and no image. Found faulty TVS on left buffer board. Also replaced T-Con (may have damaged the original while hot air removing components, board has slight warp) and have full image but few horizontal lines on the screen. Some of the lines appears to be 2 pixel tall while others are 1 pixel tall.
- Disconnecting left and right buffer board potentially reveals problems on both sides with different signals (unless this T-Con require jumper like Samsung FB_TRDY1&3) Fault
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Hi guys! I realized you have a lot of knowledge here so i am hoping you could point me in right direction with my odd issue.
The Tv is a Philips 58PUS8545/12, it had no picture but working backlights.
Original T-con:
Opened the Tv and tested to unplug one ribbon cable at a time. With this test i could see that i got fine picture on both halves as long as there was only one ribbon cable connected, with two connected picture were gone.
First replacement T-con:
I thought it might be t-con and ordered new t-con from china(supposedly tested)... -
This was my main TV for the last 6 years. I'm not inclined to throw out a $2600 TV so quickly so I'm trying to investigate the issue.
Problem
TV was disconnected from power for 6 months during construction. When I plugged it yesterday picture was fine, after 30 seconds it dimmed then started developing horizontal lines, picture then starts to ghost vertically until it degrades into vertical streaks. TV always displays a perfect picture when cold. I can unplug TV for 5 minutes and plug it back in and picture is restored for 20 seconds. I can also keep it in standby mode... -
Hi, I have a Samsung UE50TU with:
- sound and backlight, but no picture
- when it arrived, it had a picture for a few seconds
- it keeps rebooting
- without ribbon cable between the two panel boards, it does not reboot but I have no picture
- without cable between mainboard and lcd panel, it does not reboot (but obviously i have no picture)
- when i try a tape fix, its keeps rebooting, unless I tape off pin 1 (the innermost pin). In that case it does not reboot but I have no picture.
- without cable between mainboard and lcd panel and with a jumpered...
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