Sasmung la40m81bd - Recapped

[Amraks]

History:
PSU only recapped.
This TV was not turning on a few weeks ago I then recapped it as I recall I swapped all capacitors except a 163v 1uf as I didn't have this value.
A few weeks pass.
The TV now is coming back to me with with a picture fault.
https://youtu.be/sYJE7VpX4yE
Any idea what may cause this? could it be that 163v 1uf I didn't recap?

Just want this customer to have their tv back as I have their other one at the moment as well.

[Hamie]

Re: Sasmung la40m81bd - Recapped

Try heating the main board metal shield. If the picture comes back then it's probably the 2 x 1000uf caps under the tin work.

[Amraks]

Re: Sasmung la40m81bd - Recapped

They where replaced though with new ones. forget which brand I used for them.
Ill check their ESR when it comes back.

Any idea what the 1uf 163v would do?

[Amraks]

Re: Sasmung la40m81bd - Recapped

Oh Oops just noticed you meant the mainboard I originally recapped the PSU board.

[drussell]

Re: Sasmung la40m81bd - Recapped

Just a quick aside... There is no such thing as a 163 volt capacitor rating. 63? Yes. 100? Sure. 150 or 200? Yup...

Even 160 and 165 are something that (while rare), do actually exist but I've never seen a 163 volt capacitor.

[Amraks]

Re: Sasmung la40m81bd - Recapped

its a 160v not sure how I got 163v.

I can not see how it could be a cap on the mainboard as they are smd

[nomoresonys]

Re: Sasmung la40m81bd - Recapped

Video resembles a tcon problem?

[Amraks]

Re: Sasmung la40m81bd - Recapped

Heres a better video now I have the tv in my hands.
https://youtu.be/d3zCpfB23Sg

[budm]

Re: Sasmung la40m81bd - Recapped

its a 160v not sure how I got 163v.

I can not see how it could be a cap on the mainboard as they are smd

What do you mean by ' how it could be a cap on the main board as they are SMD'? SMD is just a form factor, so if it is SMD lytics cap then they can still fail just like other lytics caps.

[Amraks]

Re: Sasmung la40m81bd - Recapped

I thought they where rare to fail budm.

[nomoresonys]

Re: Sasmung la40m81bd - Recapped

Try heating things with a hairdryer on the mainboard and tcon, see if picture changes and maybe the one ribbon at a time tcon check.

[Amraks]

Re: Sasmung la40m81bd - Recapped

I checked both sides of the tcon left and right, left side pulled was white with right side still showing this defect.
right side pulled was the same as well but opposite.

heated up around the main-board and tcon the problem doesn't go away.

[nomoresonys]

Re: Sasmung la40m81bd - Recapped

Check the capacitors on the tcon for shorts, tv unplugged, meter in diode mode.

[Amraks]

Re: Sasmung la40m81bd - Recapped

checked all caps for shorts on the tcon board couldn't find any shorted

[Amraks]

Re: Sasmung la40m81bd - Recapped

I replaced that cap on psu that I didn't have before problem is still there.

[nomoresonys]

Re: Sasmung la40m81bd - Recapped

Maybe test the voltage regulators on mainboard, tutorial if needed in budm's signature post #9.

[Dannyx]

Re: Sasmung la40m81bd - Recapped

I believe you removed the video.

I'm just going to give my 2 cents nonetheless by saying it's probably a T-con issue since you're saying both sides of the screen display the same. Ideally, you'd have a second main board/T-con to compare how each performs.

Do some measurements on the t-con board: there should be test points labeled VCC, 1.2v, VGH, VGL, etc. Really curious to see how this telly gets fixed

[Amraks]

Re: Sasmung la40m81bd - Recapped

Here is a photo of the tcon all the VCC lines seem to match their values I can't find vgh or vgl

[budm]

Re: Sasmung la40m81bd - Recapped

How about AVDD, AVDD_1, VDD around the left side of the board around IC8?
You can also look up the spec sheet of that IC8 TPS65160A to see how many output Voltage sources it has.

[Amraks]

Re: Sasmung la40m81bd - Recapped

Some more photos