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

[budwich]

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

:-( it appears that the structural design of the 80 is different from the 70 which has a plastic "plate" covering the lower edge boards. I am not sure that it is worthwhile doing further disassembly at this time. It is disappointing that the shutdown does provide some form of "code flashing" or otherwise to indicate some sort of error code. Your tests that the system does detect a totally disconnected tcon from the MB indicates that the system is somewhat functional and that some other fault is causing the shutdown.

One note on disassembly beyond this point, I used blocks of wood strategically placed on the various points of the "metal back plane" to set the panel on so that I could leave everything connected and still get access to screws / hardware to remove the front bezel which then gives you access to edge boards / tabs that connect to the panel.

One other note: there is a couple other threads dealing with 80 in panels that you should read... they might provide some further information.

[nomoresonys]

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

You can download firmware on this page, guess you put the usb with the update in then plug in tv, should update by itself. It won't fix it if firmware isn't the problem but it won't hurt any. https://siica.sharpusa.com/product-downloads

[nomoresonys]

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

Your problem seems similar to this one right below. https://www.badcaps.net/forum/showthread.php?t=63849

[budwich]

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

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)?

you night try monitoring the ERROR pin / connection at power plug in, power on, and at shut down to see if thats the "flag" for shutdown... probably... maybe.

[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.

Double checked and am definitely getting 4.5 - 4.8v on the ground pins when the TV is on (only for a few seconds until it shuts off, then it drops down to 0v).

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.

Not sure exactly what you mean here. I tried using a 2k resistor (only thing I had on hand) between the ps-on and ground, then also between pnl_pow and ground, hoping it would turn on the LCD but didn't get any results.

One other note: there is a couple other threads dealing with 80 in panels that you should read... they might provide some further information.

Did some digging and I saw some power board and backlight issues, and some issues that registered an error code, but I haven't spotted anything similar just yet. I'll do some more perusing to see if I missed anything.

Your problem seems similar to this one right below. https://www.badcaps.net/forum/showthread.php?t=63849

I so wish this was my problem. Sounds like these guys are getting stuck in a reboot loop. Mine powers up, stays on a few seconds and then shuts down completely. Tried it anyway with both a 2Gb and a 32Gb (didn't have any 1Gb USBs hanging around) and there was no change in behavior. Seems like it didn't even register it was plugged in and shut off as usual.

you night try monitoring the ERROR pin / connection at power plug in, power on, and at shut down to see if thats the "flag" for shutdown... probably... maybe.

Tried this and it does seem to be spiking in voltage after the screen blips out. While the screen is on (first 4 seconds) it is at 1.4v then bumps up to 2.5v after the screen shuts off, it stays at 2.5v for a few seconds until I hear a click from the power supply and then drops to 0v.

[budwich]

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

So you need to trace that error pin to see where it goes... I am assuming it comes from the tcon.... but you can confirm that. IF so, that would likely mean that the tcon is shutting the system down maybe.

[nomoresonys]

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

"Not sure exactly what you mean here. I tried using a 2k resistor (only thing I had on hand) between the ps-on and ground, then also between pnl_pow and ground, hoping it would turn on the LCD but didn't get any results" NO you don't use the ground, you use the 5 volt, you need to jump 5 volt with ps-on and pnl-pow. to see a display NOT ether or, you DO NOT use ground, afaik.

[nomoresonys]

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

.

[nomoresonys]

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

Guess youy could try a tcon, one there for 32 bucks has a make offer option too. https://www.ebay.com/itm/SHARP-LC-80...-/371882999505

[jackf-nc]

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

Any updates on this? I am having EXACT same issues. Have replaced main board with same results (sharp logo and then off) after 4-5 secs.

[Donmessi]

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

Where you able to fix the problem on your tv?