Sharp LC-60LE600U Automatic Power Off

[willy299]

Hey Badcaps community,

I have a Sharp LC-60LE600U that has a unique problem that I cannot find a solution for. The TV, when plugged in, will light up the power light for approximately 12 seconds. At around 8 seconds, the backlight LED's will turn on for about 3/4 of a second before turning off again, followed by the power light turning off.

I have replaced the main board and the power board, and the problem is the same with either board replaced with the power-on sequence being the same time no matter which board.

I'm looking into grabbing a T-Con board, as it's the only part I haven't replaced, but I'm getting close to my wit's end. Does anyone have any other ideas? The T.V. does not respond at all to any of the controls being pressed (i.e. power button).

Attached are pictures of the TV powered off, the TV with the power light on, and the brief moment that the backlight LED's turn on.

Thanks in advance!

Imgur Album (3 pics)

P.S. - I have tried all the reset techniques (volume+power+channel buttons, holding power for 10 seconds while unplugged, etc)

[budwich]

Re: Sharp LC-60LE600U Automatic Power Off

disconnect, one at a time, the tcon to panel cables and see if that changes anything in the powering and display. Go from there.

[willy299]

Re: Sharp LC-60LE600U Automatic Power Off

disconnect, one at a time, the tcon to panel cables and see if that changes anything in the powering and display. Go from there.

Thanks for your response.

I tried the following with my T-con board:
Left ribbon disconnected, no change
Right ribbon disconnected, no change
Both ribbons disconnected, no change
Both ribbons + LVDS cable disconnected, no change
Power (I think, cable comes from power board) disconnected, no change

Does this mean that my problem doesn't lie with the T-con board? If so, does that mean the problem is not in any of my boards, but within the panel itself? Like I said in the OP, really strange symptoms with this TV. Thanks again.

[budwich]

Re: Sharp LC-60LE600U Automatic Power Off

well, these are just "preliminary" tests that do some quick checks. Now the further checks.... get a meter and start checking the voltages at the pins on the power card... there is a label legend usually printed on it and or the main board. If you post the results including the labels for each reading, the forum may be able to assist with further troubleshooting / fault isolation.

Note: you need to watch the voltages / pins before and after the set shuts down so it will take lots of attempts.

Lastly, it is quite possible that you have a backlight problem.

[willy299]

Re: Sharp LC-60LE600U Automatic Power Off

well, these are just "preliminary" tests that do some quick checks. Now the further checks.... get a meter and start checking the voltages at the pins on the power card... there is a label legend usually printed on it and or the main board. If you post the results including the labels for each reading, the forum may be able to assist with further troubleshooting / fault isolation.

Note: you need to watch the voltages / pins before and after the set shuts down so it will take lots of attempts.

If I don't have a voltage meter, but I replaced the board itself, does that rule out the power board as being an issue? Or will testing the voltages on the power board expose problems underneath/within the panel?

[budwich]

Re: Sharp LC-60LE600U Automatic Power Off

well that depends on the source of the board.... most boards "floating around the net" are not new and are taken / recycled from other sets with little guaranty that they are fully tested even if the "supplier" (usually a "third party" / non manufacturer).

However, if you assume the cards were good and nothing changed, it would likely point to problems elsewhere... which is my first guess of the backlight problem.
There are usually ways to force on the backlighting... one disconnecting the main board from the power supply (I think) but no all sets follow this. Search of the forum may provide / confirm a method.

[willy299]

Re: Sharp LC-60LE600U Automatic Power Off

I think that you're correct and that this is a backlight problem - when I disconnect the power board from the backlight (the cable that runs from the power board to the top of the TV in the image I posted), the LED's completely fail to come on and instead I get an error code, where the power light flicks on for 0.25~ seconds and then off for about 1 full second over and over. However, the power light does stay on, which leads me to believe it is a backlight problem. Do you have any idea on how difficult it is to diagnose/fix a backlight problem? Thanks again for all your help!

[budwich]

Re: Sharp LC-60LE600U Automatic Power Off

"millions" of posts about replacing backlighting. You are flying blind without getting a meter to do some checks.

did you try the disconnect the main board from the power board to see what happens. Your test of disconnecting the backlights just indicates that the system is able to notice a "totally open" back light circuit (ie. broken wire) which means that you don't have that problem otherwise you would see no change between connecting and disconnecting the lights. Most sets with backlight failure conditions have a few leds in the string that are a problem causing the circuit to detect an over / under currect condition.

Personally, I have never attempted a backlight replacement, but many many have. It most depends on getting the replacements (which usually are some what difficult to find as OEM makes don't provide these) and having space to work with the large set and taking apart the layers WITHOUT cracking the panel. Lots of shops won't attempt the repair because of the risk and ultimately the cost as tv continue to come down in cost while labor / repair costs continue to be relatively high unless you DIY.

Further on you test of disconnecting the backlights, IF you had a meter you could test the voltage when disconnected and when connected, this may give you a hint at whether the backlights are an issue. Meters can be had readily thru most of the US for less than $20.

[willy299]

Re: Sharp LC-60LE600U Automatic Power Off

"millions" of posts about replacing backlighting. You are flying blind without getting a meter to do some checks.

did you try the disconnect the main board from the power board to see what happens. Your test of disconnecting the backlights just indicates that the system is able to notice a "totally open" back light circuit (ie. broken wire) which means that you don't have that problem otherwise you would see no change between connecting and disconnecting the lights. Most sets with backlight failure conditions have a few leds in the string that are a problem causing the circuit to detect an over / under currect condition.

Personally, I have never attempted a backlight replacement, but many many have. It most depends on getting the replacements (which usually are some what difficult to find as OEM makes don't provide these) and having space to work with the large set and taking apart the layers WITHOUT cracking the panel. Lots of shops won't attempt the repair because of the risk and ultimately the cost as tv continue to come down in cost while labor / repair costs continue to be relatively high unless you DIY.

Further on you test of disconnecting the backlights, IF you had a meter you could test the voltage when disconnected and when connected, this may give you a hint at whether the backlights are an issue. Meters can be had readily thru most of the US for less than $20.

Youtube Tutorial Embed

Found a YouTube tutorial that demonstrates the same problem I have (on the same television no less) - the power light turns on for a moment before turning off. Seems like it could be related to the LED strips, and it looks like I could grab some from ShopJimmy for only $80. Gonna see if I can't unpack the TV and test the strips, will be investing in a meter.

On the off chance I do damage the T.V., I picked it up for only $50 as it had this issue to begin with, and selling all three boards on eBay will more than make up for that price if I fail to fix it. Thanks again.

[budm]

Re: Sharp LC-60LE600U Automatic Power Off

Why don't you invest on getting the meter first?

[budwich]

Re: Sharp LC-60LE600U Automatic Power Off

op, you might want to do a check around this thread's info.
https://www.badcaps.net/forum/showthread.php?t=74251