TV won't turn on high pitched noise from power supply board

[FerretFiend]

I purchased this TV less than 3 months ago brand new from Target and it's already broke. Target won't take it back and the manufacturer won't repair it because I don't have the receipt and Target can't get me a new one.

So I'm here looking for help troubleshooting my problem. I was watching a quick show while eating and a high pitched sound started, the display flashed multi-colored vertical and horizontal lines and then when black.

I unplugged it and the sound stopped, plugged it back in and it started again, TV hasn't turned on since though the LED “off” light stays on (it blinks when it turns on).

It is a:
TCL 55US5800
S/N 1609GTC000803A02482

I've done a little research and it seems like it could be the capacitors. I listened through a paper towel tube and the loudest ones are the 2 big ones I bent up and the single one at the bottom but for consistency I would like to replace every big capacitor on that board.

I had only the power supply board plugged in with the 2 connections going to the other boards unplugged at one point and it changed the sound, it was much quieter.

I need help making sure replacing the capacitors will likely fix my problem or if something else got shorted out or something else is causing this load problem on the caps.

The other thing I need help with is finding the right capacitors to buy so that I can replace them. I'm a biomed (medical equipment technician) by trade and have a little electrical component experience and board troubleshooting and soldering. I have access to a DMM and possibly a cap tester, an oscilloscope and DC power supply if needed.

Capacitor values I've seen:
56uF 450V
680uF 25V
22uF 60V
220uF 50V

Images to come after I get a hosting site, photo bucket you apparently have to pay for now!

[FerretFiend]

Re: TV won't turn on high pitched noise from power supply board

[budm]

Re: TV won't turn on high pitched noise from power supply board

Made in Sept 2016, that is a year ago, and you bought it 3 months ago?
So what kind of Voltage testing have you done so far?
What are the Voltage on those pins of the connector of the power supply board that goes to the main board? Those pins have label so make sure to report the each pin name and follow by the DC Voltage reading for each pin.

[FerretFiend]

Re: TV won't turn on high pitched noise from power supply board

Yes made a year ago and purchased on June 12th of this year. I don't have my DMM with me it's sitting at work so I haven't done any testing. I don't see any voltage labels except for the low voltage chart thing and I don't see labels on the board that match. The longer connector going inside the TV to the LED's are labeled mostly LED + and LED - where as the shorter connector going to the main board is labeled just pins 1 - 14. Is this what you were asking, measure the voltages on each pin?

[dskall]

Re: TV won't turn on high pitched noise from power supply board

Can't zoom on your pictures. Would work better if you post under go advanced. Manage attachments

[FerretFiend]

Re: TV won't turn on high pitched noise from power supply board

I tested 3 of the caps making the most noise and they tested fine, what do you guys think is the problem? I'll get voltage readings sometime this weekend if I'm not busy. Thanks for your guys help!

[attainteddragon]

Re: TV won't turn on high pitched noise from power supply board

highly unlikely to be a cap problem.

until you list voltages from the ps to the main board, we can't progress any further.
the harness in question has 2 layers of cables and we need all voltages in stby and when you have attempted to power on.

[dskall]

Re: TV won't turn on high pitched noise from power supply board

Is it making noise in standby or when you try to power it on?

[FerretFiend]

Re: TV won't turn on high pitched noise from power supply board

Ive done a little more troubleshooting this morning. It does make this noise is standby and the noise doesn't change when I attempt to turn it on. The noise changes when the main board is unplugged, it changes to a kind of clicking sound with a pattern to it.

When I measure the voltages on the pins what do I use for ground/return/black lead? Do I use the posts in the corners?

[attainteddragon]

Re: TV won't turn on high pitched noise from power supply board

anywhere on the back cover of the panel is fine for cold ground reference.

[tom66]

Re: TV won't turn on high pitched noise from power supply board

The metal frame of the TV is fine, e.g. the wall mount bracket holes, or screw holes into metal.

[apd_jack]

Re: TV won't turn on high pitched noise from power supply board

Hello,
I wonder that is there any solution found for this issue? Cause i'm having very similar one too
My replaced mainboard is causing noise from PS, or at least i think it is...

Cheers

[freakaftr8]

Re: TV won't turn on high pitched noise from power supply board

The sound probably manifests itself because of a shortage voltage on the main board loading the power supply down. You say you replace your maid board? So does the tv work now?

[apd_jack]

Re: TV won't turn on high pitched noise from power supply board

@freakaftr8 Yes, tv works fine.
It is kind of silly actually;
I replaced my LG 47 inch LX6900's mainboard with a mainboard from same model's 55 inch (don't ask why )
It works perfectly fine except that noise.
And yes, most probably it causes voltage shortage to PS cause it thinks it feeding a 55" screen.

But i don't know what can i do to fix it since it's not about capacitor malfunction.
I mean, is there any way to decrease mainboard's power consumption, or should i increase Power supply's voltage circulation somehow?

[freakaftr8]

Re: TV won't turn on high pitched noise from power supply board

I'm not sure if that's is needed. Sometimes coils just make noise for no apparent reason. Also if the output voltage of the power supply on individual pins match up with the input voltage requirements of the main board then there's no reason to switch up the voltages At last there's a certain section of the made board requiring more or less voltage.

But in this case eventually something when manifest up to an improper displaying screen or firmware problems or audio problems Which you do not seem to have

[apd_jack]

Re: TV won't turn on high pitched noise from power supply board

I'm not sure if that's is needed. Sometimes coils just make noise for no apparent reason. Also if the output voltage of the power supply on individual pins match up with the input voltage requirements of the main board then there's no reason to switch up the voltages At last there's a certain section of the made board requiring more or less voltage.

But in this case eventually something when manifest up to an improper displaying screen or firmware problems or audio problems Which you do not seem to have

No, there is no problem with screen, operating system or auido. Only this annoying signal kind of noise.

Actually, i don't know if there's any section of the mainboard requiring more or less voltage. New board is slightly different then previous one. It has some extra pins, yet it's fine without plug them.
I should check it with voltameter, right? in order to figure out which parts hightened up its voltage requirements..

I wonder, even if i spot them, will there be any way to disable them without breaking the board ?

[freakaftr8]

Re: TV won't turn on high pitched noise from power supply board

If you could take a snapshot of the power supply connector and then the main board connector and look and see if there's any kind of legend on there that shows the pin outs we might be able to see if there's any differences

[apd_jack]

Re: TV won't turn on high pitched noise from power supply board

If you could take a snapshot of the power supply connector and then the main board connector and look and see if there's any kind of legend on there that shows the pin outs we might be able to see if there's any differences

Here are some pictures of the chassis and board layout.
Weird thing is, the sound not coming from Ps but this little board at left edge corner of the chassis, it stands at the back of the remote sensor and intelligent sensor. You can also see it in the pictures.

Do they make sense?

@freakaftr8 Thank you very much by the way man. I appreciate your interest.

[budm]

Re: TV won't turn on high pitched noise from power supply board

https://www.badcaps.net/forum/attach...1&d=1523494009
This board?

[apd_jack]

Re: TV won't turn on high pitched noise from power supply board

https://www.badcaps.net/forum/attach...1&d=1523494009
This board?

Yes.
Its cables coming from Ps though, when they are unplugged sounds stops but this time Tv can't be turned on..
What is it then?