Sony KDL-48R550C, need comments is it Panel FAILURE?

[jeremykum]

I hope some experienced tech here can offer some advice.
Is this TV panel failure?

Starts up normal, with bright SONY logo. In about 1 second, the logo colour distorted and as can see in the picture, the whole panel have some artifacts and distortion. Then the screen is black without any picture. Have backlight, have sound playing from the HDMI input as long as I don't power off the unit.

Here I attach 2 photo, which I tried my best to snap it.

Thanks in advance.

[Andrew F. Ali]

Re: Sony KDL-48R550C, need comments is it Panel FAILURE?

Did you check the T-CON Bd fuse (F1) to see if you have 5Vdc or 12Vdc on either side also the other T-CON Bd voltages?:
1. Von/Vgh - (20~30Vdc)
2. Voff/Vgl - (-5~-8Vdc)
3.Vdd/Vlogic - (3.3Vdc)
4. Vda/Avdd - (13~20Vdc)

[jeremykum]

Re: Sony KDL-48R550C, need comments is it Panel FAILURE?

Did you check the T-CON Bd fuse (F1) to see if you have 5Vdc or 12Vdc on either side also the other T-CON Bd voltages?:
1. Von/Vgh - (20~30Vdc)
2. Voff/Vgl - (-5~-8Vdc)
3.Vdd/Vlogic - (3.3Vdc)
4. Vda/Avdd - (13~20Vdc)

Thanks for the assistant.

TCON F1 fuse both ends have 11.98v (12v)
One part, HAVDD_8.5V, this pad only have a supply of 8.5V when I was powering up the unit. In an instance, its gone back 0v. Something is not right here. Its directly comes from RT6929 (still trying to search the datasheet)

Can enlighten me what is this HAVDD ?

[Andrew F. Ali]

Re: Sony KDL-48R550C, need comments is it Panel FAILURE?

Replace the T-CON Bd. One of the ICs and probably associated components gone bad. Easier to replace than repair, yes even less cost to replace than repair.

[jeremykum]

Re: Sony KDL-48R550C, need comments is it Panel FAILURE?

Replace the T-CON Bd. One of the ICs and probably associated components gone bad. Easier to replace than repair, yes even less cost to replace than repair.

Afraid have to locate and replace the IC. Here is the TCON for this model

[jr.rivera.p]

Re: Sony KDL-48R550C, need comments is it Panel FAILURE?

I have exactly the same problem, could you please tell me how you fixed it

[jeremykum]

Re: Sony KDL-48R550C, need comments is it Panel FAILURE?

I have exactly the same problem, could you please tell me how you fixed it

Suspecting RT6269 but cannot confirm at this moment. Didn't manage to locate datasheet and schematic.

After powering up, the tcon have all power voltage. And lost some of it. Now I also notice the 28v also just available for a second or two, then cut off.

This is not an easy job, as can't remove tcon from assembly. I don't have equipment to affix the tcon pfc back to the led panel.

[aljita]

Re: Sony KDL-48R550C, need comments is it Panel FAILURE?

Hello. Somebody with datasheet? Or solution??

[Andrew F. Ali]

Re: Sony KDL-48R550C, need comments is it Panel FAILURE?

On further investigation, I believe that TFTs within the Panel are shorting/defective as a result you are getting voltage drops/loss at those test points. So I will suggest irreparable unless you can access the exact Panel for replacement.

[freakaftr8]

Re: Sony KDL-48R550C, need comments is it Panel FAILURE?

If I were you A would try disconnecting the ribbon cables from the tcon to the panel then measure output voltages and see if they stay high

It's they do try one ribbon cable at a time and see if the voltage is stay high and you have a good picture on 1 side I will be a definitive answer. I would say side tab gate drivers shorting

[Davi.p]

Re: Sony KDL-48R550C, need comments is it Panel FAILURE?

12v on tcon fuse even after problem appears? If yes i would warm up with soldering iron each power section semiconductor starting from power transistors/fets, if you switch on at cold and see immediately defect, then change it.Bye.

[jeremykum]

Re: Sony KDL-48R550C, need comments is it Panel FAILURE?

Ok, I am back at this TV after months. And found the problem. But it is not easy to replace the faulty chip. A FBGA. This LTF62B0. Going to buy from China about USD2, later I update once I fix and try it.

[jeremykum]

Re: Sony KDL-48R550C, need comments is it Panel FAILURE?

If I were you A would try disconnecting the ribbon cables from the tcon to the panel then measure output voltages and see if they stay high

It's they do try one ribbon cable at a time and see if the voltage is stay high and you have a good picture on 1 side I will be a definitive answer. I would say side tab gate drivers shorting

I don't have equipment to fix the pfc back if I pull it out

[Davi.p]

Re: Sony KDL-48R550C, need comments is it Panel FAILURE?

How do you found the faulty IC?

[budwich]

Re: Sony KDL-48R550C, need comments is it Panel FAILURE?

I don't have equipment to fix the pfc back if I pull it out

I think you misunderstand... feakaftr8 is referring to the "unclampable cables" not the solder / bonded ones.

[Davi.p]

Re: Sony KDL-48R550C, need comments is it Panel FAILURE?

freak is been clear, he don't noticed that jeremy can't unplug tcon output cables..

[freakaftr8]

Re: Sony KDL-48R550C, need comments is it Panel FAILURE?

Ok i see now. Tcon embedded on the FRC. Oh boy. Did you use heat or freeeze spray to find out that IC was bad?

[Davi.p]

Re: Sony KDL-48R550C, need comments is it Panel FAILURE?

i have doubts that that big ic is the faulty part, usually central tcon ics have no control on power supply part of the board, so if havdd =half avdd = 17v/2= 8,5v is present only for few instants, probably some part of the pwr supply section is bad or panel is shorted.

[aljita]

Re: Sony KDL-48R550C, need comments is it Panel FAILURE?

ok, i am back at this tv after months. And found the problem. But it is not easy to replace the faulty chip. A fbga. This ltf62b0. Going to buy from china about usd2, later i update once i fix and try it.

hello. Could you fix? I have two same problem. Plesa coment!

[nomoresonys]

Re: Sony KDL-48R550C, need comments is it Panel FAILURE?

Ok, I am back at this TV after months. And found the problem. But it is not easy to replace the faulty chip. A FBGA. This LTF62B0. Going to buy from China about USD2, later I update once I fix and try it.

Any followup?