intermitted shutdown at high brightness

[Demonata08]

Just curious. What board is typically at fault in a lcd tv that shuts down around 10-20 minutes. It turns right back on and normally works fine after it goes off. Lowering the brightness seemed to elevate the issue.

all caps on the P board and the voltage is all good. I can post pictures if needed but im just curious what the typical issue is.

[diif]

Re: intermitted shutdown at high brightness

Faulty LED(s)

[petehall347]

Re: intermitted shutdown at high brightness

turn back lights down problem solved for now and x amount of time .

[Demonata08]

Re: intermitted shutdown at high brightness

Faulty LED(s)

It fails after about 2 minutes even if the panel isnt plugged up and just with the backlight. with it unplugged i can still hear the sound. it goes off at the same speed ><

the voltage is steady 13 until it recieved the error signal. thinking its the main board at the moment

[budm]

Re: intermitted shutdown at high brightness

Makes, model, and pictures will help since we have no idea what you have at all.

[ducky29]

Re: intermitted shutdown at high brightness

Is it LG?

[Demonata08]

Re: intermitted shutdown at high brightness

Makes, model, and pictures will help since we have no idea what you have at all.

Its a sharp lc-c3234u i believe. I learned something new about esr testing. So right now the p board may actually be the problem. Got an esr meter on the way now.

[nomoresonys]

Re: intermitted shutdown at high brightness

Heat the powerboard with a hairdryer, see if tv stays on longer.

[budm]

Re: intermitted shutdown at high brightness

You need to show us the pictures of the whole backside of the TV showing all the boards, this TV has more than one versions: It has CCFL backlights.
https://www.shopjimmy.com/catalogsea...harp+lc-c3234u

[Demonata08]

Re: intermitted shutdown at high brightness

Heres the back.

Thanks guys.

[Demonata08]

Re: intermitted shutdown at high brightness

So just a quick update. ive now went through every component on the power board that i can check. the esr meter i got in has shown every capacitor is in excellent condition except the two big ones on the board. They are 220v 470uf but are showing 450uf, .23esr, I do believe thats close enough to the marked value to not cause problems, but since everything else on the board is good im not sure what else it could be.

I do notice when its on the main transformer gets remarkably hot. Not like, burn to the touch hot, but still pretty hot.

[jetadm123]

Re: intermitted shutdown at high brightness

Sounds like you have a heat related problem. Maybe a bad solder joint? I suggest you do as nomoresonys recommended and heat up each board with a hairdryer to see if you can shorten the shutdown time.

[Demonata08]

Re: intermitted shutdown at high brightness

Sounds like you have a heat related problem. Maybe a bad solder joint? I suggest you do as nomoresonys recommended and heat up each board with a hairdryer to see if you can shorten the shutdown time.

I shorted out the error detection on the power supply board to see if it was the LEDs or power supply and so far its been on for about an hour at full brightness. I have no idea what to think about that.

Ive been thinking it was either the leds or the power supply board. if i short out the error code it wont turn off when it detects an error so if the leds are bad i can shine a light through the tv and see the picture and if its the power supply i would imagine the whole tv would just power off.(or so thats my thinking)

gonna continue to let it run and see what happens.

[budm]

Re: intermitted shutdown at high brightness

Your TV dose not use LED for backlights, it uses CCFL for backlights. If one lamp is bad it will shutdown the inverter circuit.
Remove the inverter board from the sockets and inspect the sockets and the contact fingers of the inverter board that fit into the sockets.
Try turning down backlights level (not Brightness) to see if it will take longer for the backlights to go off. You may have worn backlights, you can also check to see if any one of the Inverter transformer is hotter that the other, check it after the Bcklights go off and TV is unplugged.

[Demonata08]

Re: intermitted shutdown at high brightness

Your TV dose not use LED for backlights, it uses CCFL for backlights. If one lamp is bad it will shutdown the inverter circuit.
Remove the inverter board from the sockets and inspect the sockets and the contact fingers of the inverter board that fit into the sockets.
Try turning down backlights level (not Brightness) to see if it will take longer for the backlights to go off. You may have worn backlights, you can also check to see if any one of the Inverter transformer is hotter that the other, check it after the Bcklights go off and TV is unplugged.

Yep didnt realize the led thing when i was thinking about it. went back to it and realized afterwards. There wasnt any kind issue with the sockets that i could see. I wasnt sure how to test the inverter transformer and i had already had a power supply from a similar board with the same exact numbered inverters. so i swaped them over carefully and so far its been on for about 4 hours straight at highest backlight. I'm not sure which one of these transformers is bad, i wish i did, because i feel like itd be a good spare part to have around haha.

But either way its fixed, hazzah!

(EDIT: I shouldnt say its fixed just yet. Im gonna let it run for the rest of the day, But it before it would last around 5 minutes at high backlight so im pretty confident it is fixed )

[nomoresonys]

Re: intermitted shutdown at high brightness

Was probably just one bad transformer, some model tvs are easier to test transformers than others.

[Demonata08]

Re: intermitted shutdown at high brightness

Was probably just one bad transformer, some model tvs are easier to test transformers than others.

I have a pretty good feeling it was just one. But short of taking turns putting one at a time back in til it errors again is way not worth my time.

This one stayed on for 24 hours straight so i felt comfortable enough selling it. As it turns out the exact same model with the exact same problem has popped up again except this one only stays on for a few seconds(not enough time to adjust the backlight) im gonna crack it open in a few days and hopefully its the same problem.

[nomoresonys]

Re: intermitted shutdown at high brightness

NAH, I wouldn't do that either, I'd just test each transformer. http://jestineyong.com/test-lcd-inverter-transformer/