SHARP AQUOS LC-70LE836S only blinking - freebie

[olegeisler]

Got this SHARP AQUOS LC-70LE836S for free - did some basic troubleshooting, and found manual - without detail schematics though. Comes from a meeting room with extremely few working hours.

Symptoms :

When connected to mains, the logo blinks continously, approx 6 times per 10 seconds.

A press on MENU as per the manual changes this to one short blink, one long and then repeats.

Only 5V ( Standby ) on PSU module present, no AC_DETECT, no 12V, no 13V, no PS_ON from mainboard.

As I see it mainboard has some kind of life, but does not ask for the PS_ON, so probably a bad mainboard......

Any suggestions for what I can try, or anyone who can point to a detail schematic ?

[nomoresonys]

Re: SHARP AQUOS LC-70LE836S only blinking - freebie

take your time, do this, unhook cable from powerboard to mainboard, leave it unhooked, plug power cord into powerboard, recheck the pin for ac-detect, if still missing it's a powerboard issue.

[dskall]

Re: SHARP AQUOS LC-70LE836S only blinking - freebie

Heat up main processor and see if it will power on.

[olegeisler]

Re: SHARP AQUOS LC-70LE836S only blinking - freebie

Thanks - checked, no AC_DETECT - will check Power supply circuit, this should be well within my capabiities, even without schematics

[nomoresonys]

Re: SHARP AQUOS LC-70LE836S only blinking - freebie

maybe try the powerboard as stand alone, by unhooking the cable from powerboard and mainboard, then jumping probably ps-on and bl-on with standby pin, some use resistors for jumping so they don't short something by accident. Then see if you have the backlights on and the expected voltages on the pins. May have to add jumper from pwm to standby as well, the bl-on may be called ofl, standby may be called bu5.

[dskall]

Re: SHARP AQUOS LC-70LE836S only blinking - freebie

Thanks - checked, no AC_DETECT - will check Power supply circuit, this should be well within my capabiities, even without schematics

Sorry, didn't pay enough attention to post. Will need to run down detect problem.

[olegeisler]

Re: SHARP AQUOS LC-70LE836S only blinking - freebie

maybe try the powerboard as stand alone, by unhooking the cable from powerboard and mainboard, then jumping probably ps-on and bl-on with standby pin, some use resistors for jumping so they don't short something by accident. Then see if you have the backlights on and the expected voltages on the pins. May have to add a jumper from PWM to standby as well, the bl-on may be called ofl, and standby may be called bu5.

Took a little reverse engineering - but now I know that the AC_DETECT is only functional when the PS_ON is active. Feeding the PS_ON with BU5 (Standby 5V ) via a 1K resistor turns on the 13V PSU, and then the AC_DETECT goes to 3V3.

I guess it smells like a motherboard issue, but it can be purchased at a low price. So, unless anyone has some very good suggestions, I will invest in a mainboard. Makes little sense to try to do anything with the mainboard without a proper schematic - and the chance that it is the big BGA is probably high....

[nomoresonys]

Re: SHARP AQUOS LC-70LE836S only blinking - freebie

Nice work, that's the other thing I suspected, it is looking like mainboard problem.

[olegeisler]

Re: SHARP AQUOS LC-70LE836S only blinking - freebie

Nice work, that's the other thing I suspected, it is looking like mainboard problem.

Set is working !

Found this https://electro-medical.blogspot.com...c-70le838.html and it seems if a fault is detected from backlight 5 times, the set goes into this mode. I got the message that this set is highly sensitive for this, and backlight sensing should be turned off.

After clearing the error, set is fully functional, I will let it run for a long period to check if any issues, but so far the picture is perfect, backlight has no issues.

[nomoresonys]

Re: SHARP AQUOS LC-70LE836S only blinking - freebie

ok, remembering now, definitly on those sharps they lock up after I think it's 5 errors, then you have to reset.

[olegeisler]

Re: SHARP AQUOS LC-70LE836S only blinking - freebie

ok, remembering now, definitly on those sharps they lock up after I think it's 5 errors, then you have to reset.

Seems so, yes - and after clearing the error everything seems to work just fine. Picture is perfect, all OK - has been running for 20 hours now.

No parts replaced, nothing - only resetting the error in Service Menu.

Thank you for your valuable input.

PS: It only has 357 hours on the counter, so it is like new....

[nomoresonys]

Re: SHARP AQUOS LC-70LE836S only blinking - freebie

Nice, very low hours indeed and the price was perfect, lol, another fine save.

[olegeisler]

Re: SHARP AQUOS LC-70LE836S only blinking - freebie

Nice, very low hours indeed and the price was perfect, lol, another fine save.

It will probably go as a donation, or at a VERY low price, for someone in need - I will get a divorce if I try to drag 70" into the house, and I also have no genuine interest in TV as such, so...

The fun part is done now ( to get it working )

[nomoresonys]

Re: SHARP AQUOS LC-70LE836S only blinking - freebie

Cool beans, I'm like that too, it's mainly the puzzle of what's wrong and how to fix it that keeps me interested and pulling my hair out both.

[mmartell]

Re: SHARP AQUOS LC-70LE836S only blinking - freebie

I would be concerned that it's the power on sequence setting the flag not run-time (obviously no flag set when it powers on normally)

Try turning it on and off several times a day then go back in and check to see if there were any more flags set.

[olegeisler]

Re: SHARP AQUOS LC-70LE836S only blinking - freebie

I would be concerned that it's the power on sequence setting the flag not run-time (obviously no flag set when it powers on normally)

Try turning it on and off several times a day then go back in and check to see if there were any more flags set.

Good point. Will try to do random power cycling.