Sharp LC-80LE661U - Power's off after 4 seconds.

[overlyAmbitiousSloth]

Howdy Folks,
This is my first time posting with an issue so I'm including as much info as I can (whether it turns out useful or not). I don't have any experience troubleshooting LCD TV's so I'm hoping someone out there can give me some tips or maybe point me in the right direction (even if its a 'RTFM nuub' if there's a link attached).

I've got a Sharp LC-80LE661U model TV that powers on, displays the SHARP logo and then promptly turns off after about 4 seconds. There isn't anything displayed onscreen other than the logo. I've tried button combinations to perform a factory reset, I've tried opening menu's as soon as it powers on, I've tried different video inputs... but I never see anything other than the Sharp logo. And then the screen flashes for a split second and shuts down.

Once it powers down I see the standby light illuminate on a steady interval (unfortunately, no error code is being passed).


Popping the thing open I see what you would expect, power board, processor board and a t-con board. I know nothing about troubleshooting these guys so I took a close look at each and am not seeing what looks like failed components (at least nothing crispy, bulging or leaking). Then I busted out the volt meter and the readings I'm getting, I think, don't sound waaay off (at least based on what was printed on the power board).


Power board is a RUNTKB380WJQZ and I'll include a shot of what the voltages should be based on whats referenced on the PCD.

TV OFF - power applied

1- 0.3v
2- 0
3- 1.214v
4- 1.213v
5- 0
6- 0
7- 0
8- 5.04v
9- 0
10- 6.4v
11- 0
12- 0

TV ON – power applied

1 - 11.88
2 - 3.8
3 - 13.12
4 - 13.14
5 - 4.5
6 - 4.5
7 - 3.331
8 - 5.03
9 -1.427
10 - 1.294
11 - 1.427
12 - 1.427


Not sure where to go from here. I hate throwing parts at a problem until its fixed so any advice would be more then appreciated.

Thanks Folks,
Jon

[ajshoe]

Re: Sharp LC-80LE661U - Power's off after 4 seconds.

first guess would be main board.

[budm]

Re: Sharp LC-80LE661U - Power's off after 4 seconds.

You need to put down the pin name for each pin and follow by the Voltage reading so we can easily see what each pin is.

[budwich]

Re: Sharp LC-80LE661U - Power's off after 4 seconds.

In addition to those tests, you can try disconnecting the tcon to panel cables, one at a time, and see if that changes the results (of course the disconnect / connect is done without power on).

[nomoresonys]

Re: Sharp LC-80LE661U - Power's off after 4 seconds.

Try unplug tv from power outlet, disconnect cable from mainboard to powerboard, plug power cord back in turn it on, see if backlights come on and stay on.

[overlyAmbitiousSloth]

Re: Sharp LC-80LE661U - Power's off after 4 seconds.

You need to put down the pin name for each pin and follow by the Voltage reading so we can easily see what each pin is.

My bad, didn't even think to do that (I've attached a picture of the power board that lists pin names, not sure if I'm reading it properly but I've referenced the PIN names in the left column)-

TV OFF/Stand-By
PNL12V - 0.3v
GND - 0
UR13.2V - 1.214v
UR13.2V - 1.213v
GND - 0
GND - 0
AC_DET - 0
BU5V - 5.04v
PWM1 - 0
DIM - 6.4v
OFL - 0
PWM2 - 0

TV ON – power applied
PNL12V - 11.88
GND - 3.8
UR13.2V - 13.12
UR13.2V - 13.14
GND - 4.5
GND - 4.5
AC_DET - 3.331
BU5V - 5.03
PWM1 -1.427
DIM - 1.294
OFL - 1.427
PWM2 - 1.427

[overlyAmbitiousSloth]

Re: Sharp LC-80LE661U - Power's off after 4 seconds.

first guess would be main board.

Is that a common symptom of a dead/dying main board? If so, is it even worth troubleshooting components on the board or just replace the whole thing?

In addition to those tests, you can try disconnecting the tcon to panel cables, one at a time, and see if that changes the results (of course the disconnect / connect is done without power on).

Thanks for the suggestion budwich, I'll give this a shot as soon as I get home this evening and check back in with results.

Try unplug tv from power outlet, disconnect cable from mainboard to powerboard, plug power cord back in turn it on, see if backlights come on and stay on.

Thanks for the suggestion nomoresonys, I'll give this a shot as soon as I get home this evening and check back in with results.

[overlyAmbitiousSloth]

Re: Sharp LC-80LE661U - Power's off after 4 seconds.

Try unplug tv from power outlet, disconnect cable from mainboard to powerboard, plug power cord back in turn it on, see if backlights come on and stay on.

Tried but didn't turn on when I applied power. This may be a stupid question but is there a pin on the powerboard I can short to ground or something to feed it a 'power on' signal?

In addition to those tests, you can try disconnecting the tcon to panel cables, one at a time, and see if that changes the results (of course the disconnect / connect is done without power on).

When I disconnected the large ribbon cables, one at a time, and powered on half of the screen was solid white (pictures attached).

For shits and grins I started disconnecting different cables, one at a time, and powering back on. Wifi, IR receiver, speakers, button pad, data cable from main board to tcon, all didn't make any difference (well the last one stopped Sharp from displaying). Then I pulled the power cable to the tcon board and noticed the standby light flashing at longer intervals. Its not like a dot-dot-dash sequence or anything just longer dashes, if that makes sense. Was kind of expecting an error code when a main component is missing / not getting power. Is that normal?


Anyway, thanks for the suggestions guys and please keep em coming.





PS - It looks like there's an RS232 console port on the side of the mainboard. Does anyone know anything about that? I don't have a female to female serial cable or I would trying connecting to it. Being that it only powers on for a few seconds I doubt I'd be able to do much aside from maybe a receive a quick dump of a POST or something.

[nomoresonys]

Re: Sharp LC-80LE661U - Power's off after 4 seconds.

Yes you can usually jumper the powerboard pins they suggest using a resister in case you get the wrong combo, make sure the connector cable between mainboard and powerboard is unplugged when doing this test.

[overlyAmbitiousSloth]

Re: Sharp LC-80LE661U - Power's off after 4 seconds.

Yes you can usually jumper the powerboard pins they suggest using a resister in case you get the wrong combo, make sure the connector cable between mainboard and powerboard is unplugged when doing this test.

I see the following labels on the pin label for the cable between the mainboard and the powerboard:

PNL12V
GND
UR13.2V
UR13.2V
GND
GND
PS_ON
PNL_POW
NC
NC
ERROR
STB

Would it be the PNL_POW pin that I need to short to ground?

When taking power readings earlier I saw 5V on that pin. What type of resister would I need to use? Or, could I short it directly to one of the GND pins above (was seeing 4.5V on the two ground pins 5th and 6th from the top)?

[nomoresonys]

Re: Sharp LC-80LE661U - Power's off after 4 seconds.

Make sure you are identifying your pins correctly, you should have around 0 volts on the ground pins.

[nomoresonys]

Re: Sharp LC-80LE661U - Power's off after 4 seconds.

I believe you can use a 1k resistor and connect 5 volt stby with ps-on and panel 12v, maybe one of the super techs here can confirm procedure.

[budwich]

Re: Sharp LC-80LE661U - Power's off after 4 seconds.

so... the pictures that you posted seem to show some "issue" with the display.... perhaps although it could be the "photography". The "white" side that indicates the side of the tcon that is disconnected should be uniformly white. One picture appears to show some horizontal "banding" of darkness. Was this actually there or just a "poor photo" not really representative of the image that was there?

[overlyAmbitiousSloth]

Re: Sharp LC-80LE661U - Power's off after 4 seconds.

Make sure you are identifying your pins correctly, you should have around 0 volts on the ground pins.

Thanks for the heads up. I'll double check to make sure I'm reading the proper pins when I get home this evening.

I believe you can use a 1k resistor and connect 5 volt stby with ps-on and panel 12v, maybe one of the super techs here can confirm procedure.

I can give it a shot, doesn't sound too complicated. Out of curiosity, is there any sort of guide hanging around for this (I've run through some of the guides on here and they're great, just haven't seen anything on this).

so... the pictures that you posted seem to show some "issue" with the display.... perhaps although it could be the "photography". The "white" side that indicates the side of the tcon that is disconnected should be uniformly white. One picture appears to show some horizontal "banding" of darkness. Was this actually there or just a "poor photo" not really representative of the image that was there?

I've got a couple more pictures attached. Some of them show this banding effect, some of them don't. I don't have the TV base/stand so I was kinda holding the tv up with one hand, camera with the other and flipping the power strip on and off with my foot... so the pictures are definitely janky. I'll go through the same process this evening and see if it was just weird angles.

Would that point towards a poor LCD?

[budwich]

Re: Sharp LC-80LE661U - Power's off after 4 seconds.

as you can see from your pictures, the "issue" seems to be on the left side... when that side is disconnected.... while opposite "test" appears quite a bit better in terms of "uniform white". My concern would be that perhaps it is a "marginal panel issue". It would help if you feed in a known test pattern (color bars) which will potentially highly issues better. Further, you indicate at the start, that the set shuts down after 4 seconds. does it still do this with either side of the tcon disconnected? IF not, then that would point to a panel issue.... but if so, then it might indicate a problem away from the panel and more dealing with controls / boards.

One other point.... I know the panel is huge (previously I work with a 70in that was tough)... so be careful. There are small white cables in the bottom corner of the panel on each side. These cables interconnect the bottom edge boards to side edge boards. If you are careful, you can disconnect those cables... again one at a time and see the result.... keep all other cabling connected. You should see a full picture with some darkness... again use a test pattern (color bars) and perhaps your display will show you something.

[overlyAmbitiousSloth]

Re: Sharp LC-80LE661U - Power's off after 4 seconds.

as you can see from your pictures, the "issue" seems to be on the left side... when that side is disconnected.... while opposite "test" appears quite a bit better in terms of "uniform white". My concern would be that perhaps it is a "marginal panel issue". It would help if you feed in a known test pattern (color bars) which will potentially highly issues better. Further, you indicate at the start, that the set shuts down after 4 seconds. does it still do this with either side of the tcon disconnected? IF not, then that would point to a panel issue.... but if so, then it might indicate a problem away from the panel and more dealing with controls / boards.

One other point.... I know the panel is huge (previously I work with a 70in that was tough)... so be careful. There are small white cables in the bottom corner of the panel on each side. These cables interconnect the bottom edge boards to side edge boards. If you are careful, you can disconnect those cables... again one at a time and see the result.... keep all other cabling connected. You should see a full picture with some darkness... again use a test pattern (color bars) and perhaps your display will show you something.

Yep, it does still shut off after 4 seconds regardless of which of the t-con ribbon cables I had unplugged.

I've been doing some reading on feeding the t-con board a test pattern and am not finding any instructions on this type(G477FM05). I see some other boards have pins that can be jumped or shorted but I don't see anything on this board that screams 'bridge me' (I also don't really have a clue what I'm looking for, just comparing to the pictures in this post https://www.badcaps.net/forum/showthread.php?t=26790 ). I've attached a picture of the board for reference (can take better pictures later if it helps).

Any idea's on how I can get it to display a pattern?

When I get home I'll check for those cables running the bottom corner/edge of the LCD and see if disconnecting those shows new results.



PS - Found documentation on the RS232 port that I asked about earlier in the Operation Manual for the LC-80LE661U. Looks like its designed for remote control of the TV. No help in this scenario but kind of a cool option to have.

[budwich]

Re: Sharp LC-80LE661U - Power's off after 4 seconds.

multitudes of dvds (thx ones and others) have special features for tv setup / colors etc. In addition, there are computer files that provide various test patterns.

Since the system still shuts down, regardless of the tcon connections, that would imply a problem back from there. However, it may depend on why the shutdown.... voltages out of range? main board issues?

The corner cable test that I suggest is potentially still valuable depending on what happens. Still concerned about the lack of uniform white on the disconnected side.

[overlyAmbitiousSloth]

Re: Sharp LC-80LE661U - Power's off after 4 seconds.

multitudes of dvds (thx ones and others) have special features for tv setup / colors etc. In addition, there are computer files that provide various test patterns.

Since the system still shuts down, regardless of the tcon connections, that would imply a problem back from there. However, it may depend on why the shutdown.... voltages out of range? main board issues?

The corner cable test that I suggest is potentially still valuable depending on what happens. Still concerned about the lack of uniform white on the disconnected side.

Well, I disconnected the t-con ribbon cables again (one at a time) and there is definitely not a uniform white displayed. In fact, it seems a heck of a lot worse than it did last night. I may have screwed something up in the mean time. I did have the power cable plugged into a six-strip and only powered off the strip between plugging and unplugging cables instead of fully disconnecting the power. Aside from that I can't think of anything else I did that would have effected it.


Oh, and I can't get any external inputs to display. TV powers up, shows Sharp logo and then shuts off in a few seconds. I've tried multiple inputs and haven't seen anything displayed (don't see menu's either and can't get the service menu to pop up with button combinations). So that puts in me a tight spot with getting test patterns to display.


Anyway, I've got some pictures attached.

Does this look like a panel issue? If that's the case, do these type of tv's have backlight LEDs that could be replace? Or does it just mean the panel is shot?

Thanks for the help and advice.

[budwich]

Re: Sharp LC-80LE661U - Power's off after 4 seconds.

hmmm the fact that you can't connect with any external inputs doesn't sound good and points towards the amin board which houses those (I think). further, you still need to try to disconnect the small corner cables that interconnect the bottom and side edge boards... this may give you a better understand of what it happening.

[overlyAmbitiousSloth]

Re: Sharp LC-80LE661U - Power's off after 4 seconds.

hmmm the fact that you can't connect with any external inputs doesn't sound good and points towards the amin board which houses those (I think). further, you still need to try to disconnect the small corner cables that interconnect the bottom and side edge boards... this may give you a better understand of what it happening.

I may be missing something, but I've taken off the speaker mounts and bezel and am not seeing cables in the corners. The only cables I see are a couple pair of ribbon cables at the bottom of the TV. I've attached a couple pictures to give an idea of what I'm seeing. Unfortunately, I can't get the ribbon cables undone without completely disassembling the LCD housing. It looks like it would have to be loosened on all sides and then lifted up, probably just a a half inch, to disconnect those ribbon cables. Before I dive down that rabbit hole, do these look like the right cables?