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Question

Ln32a550p3f : two horizontal lines across the screen!!

Feb 19, 2015 12:00AM PST

Ladies&Gentleman,

My lcd tv shows two white colored thin horizontal lines in the bottom half of the screen when dark(no picture on). When video on, these lines go greenish-black.

First of all, I ordered and replaced a new T-con from ebay. It never helped. I realized I did a poor troubleshooting because I found most threads from google pinpointing to a defective T-con. When I unplugged two ribbon cables coming from the panel into T-con, two black horizontal lines still appear in the white display. That means that the T-con is good.
I verified the health of capacitors in power supply. no burnt, no bulged and no leaks. The inverter looks ok since backlighting still performing well. The main board (video card) seems to be ok since video does not show any issues except those black lines.

I am frustrated that I am not able to figure it out but i learned a great deal of knowledge in troubleshooting a defective lcd.

I really appreciate your great help in solving the issue.

Thanks in advance

Discussion is locked

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Answer
Sadly I've yet to find TV techs pile on such.
Feb 19, 2015 12:06AM PST

I will share some wisdom an elder engineer shared years ago. Ready? "Replace the cheapest part first" when in doubt of what part to replace next.

Diagnosing to the component level is tough without spares to swap in. And diagnostic gear for such machines are usually many thousand so that's why they send such off to service depots or just swap parts until they find it.
Good hunting,
Bob

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You must be right!
Feb 19, 2015 1:28AM PST

Thanks, Bob.

That's what I bought the cheapest part T-con ($30) but no luck. The main board cost $80, power supply $70 and inverter $60, So go figure.

I was told that the issue rested with the display panel. Not repairable because not economically viable.

Thanks once again, Bob.

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Parts as they pass 200
Feb 19, 2015 1:56AM PST

I did a quick google shopping search on 32 inch HDTV and it looks to be a price crush point about 200 bucks where I can get a new set. One of the rules of thumb is to replace as you pass 50% of new. Some get upset about that but parts can reach that too fast.

If the set works at all, maybe ebay or craigslist it and move on.
Bob

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Thanks Bob
Feb 19, 2015 6:16AM PST

I really appreciate it!

I'll probably list it online to sell it as is.

thanks Bob