Samsung OLED 4k TV repair

[ttx450]

 I acquired a samsung tv that came from a family member that was going into the trash. Its a 2 yr old 4k oled tv, no picture.

I went through the elimination process and ended up with the LED driver circuit and used the LED driver board tape method and got it to work.

It appears the problem is on the right side. I was testing some of the capacitors in circuit, I believe are in series decoupling caps. Everything is SMD, these look like extra small solder pads compared to what I normally see. If it was one of the larger caps 1/8" I might try and remove it and test. There are many.  There are some test points, but have no data.

Anyway question, I reduced my tape size down smaller around 4.5 mm and still have a picture (now 3mm). I am trying to understand blocking some of the ribbon cable connections LED, how does it effect the picture. Right now my picture looks normal splash screen. I have not played anything through it yet. Anyone worked on these?

I wonder if its possible to use a very thin piece of tape and only block 1 or 2 traces at a time. Seems like that might be better?

[ttx450]

Looks good to me.   

[james_s]

What was the problem? Bad capacitors? Or does it "fix" it to tape over some of the contacts?

[ttx450]

What was the problem? Bad capacitors? Or does it "fix" it to tape over some of the contacts?

I am suspecting bad capacitors in the OLED driver board. I traced it down to one side.  The SMDs pads are so small or not real visible I did not really want to take a chance removing to test.  The ones that are larger around 1/8" I might be temped.  Its really hard to tell whats bad without lifting them.  From what I understand when these driver boards that are attached to the OLEDs, and they are not reparable when they get real bad.  I have no lines in the screen, so I am thinking its on the board and not a led..  The color looks fine too. I did reduce the tape size and still got it to work around 3mm wide.  I just left good enough alone for now.

[james_s]

I'm confused though, how does taping off pads fix the issue without impacting the display?

[ttx450]

Trying to understand is what my original post was hoping to get.  Sometimes you end up with lines, or slightly darker areas.  Guessing my issue is in the driver board for the OLED I believe you might notice or not a degrade in intensity in parts of the screen.  So far I cannot see anything, but have not used it much.  So I am thinking it is very slight in my case.  Again this is why I was posted this trying to understand.

The main board picks up something is wrong, either to much current draw or open in my case.  So the unit goes into a reboot process over and over.  Eliminating lets it boot up.  How bad it is, will need to be determined by each tv.

[Kirkhaan]

Lots of YouTube video's about this kind of repair indeed, for example:



I also have a Samsug QLED TV (from 2019...) here that shows similar phenomena. Will dive into it coming days.