Sony KDL-40SL140 way too bright

[billydanger]

Ok, stay with me:

1. originally had solarized picture and so I replaced the TCON board.
2. After replacement I got nothing but a blank screen. Backlight was on but that was all.
3. after much searching and probing I found an open fuse on the mainboard that I must have popped somehow.
4. Replaced fuse and all functionality returned EXCEPT the screen is now really bright. Not like I have a supercharged backlight but more like the brightness is turned all the way up (which it isn't). Picture is not solarized like before TCON replacement, just too bright.

Eventually (10-15 minutes) screen will fade back down to near-normal brightness level and then return to high brightness after a few more minutes. Process repeats until I get sick of looking at it.

The mainboard fuse was F4001 (24V, 5A) and is in-line with IC number Q4018 (UPA1716G-E2). The schematic is shown in service manual page 44.

Thoughts?

[Andrew F. Ali]

Re: Sony KDL-40SL140 way too bright

Adjusting the Contrast and Brightness did not help?....There might be a Backlight adjustment in the Main Menu. too....Turn them down.

[billydanger]

Re: Sony KDL-40SL140 way too bright

Adjusting the usual options doesn't seem to help much. I can get it close to something resembling a decent picture but it just returns to the "super bright" display after a few minutes.

Also, I wiggled cables and TCON ribbon cables, as well as used a heat gun around the edge of the screen to look for bonding issues but I was never able to find anything.

[billydanger]

Re: Sony KDL-40SL140 way too bright

I tried to take a little video with my phone but naturally the TV is playing just fine right now. Maybe later...

[billydanger]

Re: Sony KDL-40SL140 way too bright

I replaced the AS15 chip on the "new" TCON board that I bought and that seems to have done the trick. Colors are still a little bit off but I think that can be fixed with proper adjustments.

So. Fixed. Bad TCON board as was the original diagnosis.

[dick_barton]

Re: Sony KDL-40SL140 way too bright

Disappointing that you had to repair the replacement Tcon but looks as though you've nailed it. Well done

[Hamie]

Re: Sony KDL-40SL140 way too bright

You may still have an issue with the gamma chip. Maybe one leg not quite soldered properly.

Many people including myself have had issues with brand new chips being faulty straight out the box.

Check your gamma voltages.