Sony KDL55HX800 Shuts Down

[PWB]

This set will come on for about 20 sec. then the screen goes dark at about the top 6 inches, then the pix dims and shuts off and gives a 6 code blink.
Also a small dim spot is always on the top left corner. Could this be a bad panel?

TIA,

Peter

[drpj23]

Re: Sony KDL55HX800 Shuts Down

Most likely a backlight failure due to the BUHT board.

Could you include a pic though of what you mean by the small dim spot always there?

[electronicsurplus]

Re: Sony KDL55HX800 Shuts Down

Look on the Left inverter and find the white wire labelled bldet, or light det or similar name. it is usually the last wire on the smaller plug. This is the backlight detection wire. clip it and, your set should turn on fine.

The problem is in an IC which does not detect the backlight as being on so it goes to safety sutdown

[drpj23]

Re: Sony KDL55HX800 Shuts Down

electronicsurplus, I'm not doubting you but i am in lack of understanding of your answer. Doesn't BL_DET require a voltage for operation? And how would that effect the backlight the way it is described? Again, I just want to know how you came to that conclusion.

Two, my answer doesn't fully describe your symptom either. The error code is that buht board but none of the codes every represent the LED drivers. I would be weary of that board too.

If clipping that wire does work, I would recommend replacing the IC or board it is on, for the safety shutdown was built for a reason.

[electronicsurplus]

Re: Sony KDL55HX800 Shuts Down

There is NO "IF" clipping the wire does work" it does.

We came to this conclusion from Sony via a Tech Newsletter, since, we are Sony Authorized, advising there was a flaw in the design. and, this is for testing purposes only to determine whether the problem was within the Main A board or the Inverter B board

Either way, we have completed this repair and, it has worked for us well on many televisions. and, we currently have several of these repairs which remain working.
therefore, we have decided to keep them this way.

some however do require that you inject 12v into the line so the Main board receives the signal that the television is lighting and does not go into shutdown.

For certain one would want to replace the inverter board B1 board and, the A board (Main) or try replacing the IC which controls this function. which is likely not practical for most people since, they may or may not have the proper tools to remove and replace this this surface mounted IC

We were only trying to provide some useful information which we had learned over the years