Sony KDL40V4100-Dark Picture

[DoubleDD]

I have a Sony KDL40V4100- Model T400HW01 - Sept 2008 manufacture, serial number 8200XXX that has just started displaying the picture very dark with red toning, meaning skin tones are rendered in abnormal reddish tint. The problem is throughout the entire screen, it does not exhibit and vertical or horizontal lines. The picture remains fairly sharp and shoes only a small amount of ghosting depending if the previous content was a chart or lettering. The menu appears normal other than the dark hue, the lamps appear to be on throughout. The whites will sometimes start whiter and then dim. I am trying to determine if this is a failure of the TCON board, the BU board or a panel failure. I obviously don't want to start hanging parts on an older LCD television but if I can keep it going that is my goal. I have checked for bulging capacitors and loose connections but have found none. Hoping someone else has seen this and can advise the best repair course. I have attached photos showing the screen, as you can see Wolf Blitzer is very red on my screen.

[DoubleDD]

Re: Sony KDL40V4100-Dark Picture

Just a note the picture on the screen is in normal upright position, attachment posting from phone shifted photos d180 degrees

[Andrew F. Ali]

Re: Sony KDL40V4100-Dark Picture

Looks like a bad T-CON Bd to me

[paulstef]

Re: Sony KDL40V4100-Dark Picture

Please post the voltages from the testpoints marked VG or VGMA on the TCON board. They should increase or decrease in sequence

[diif]

Re: Sony KDL40V4100-Dark Picture

Yeah, I would say it's the AS15 on the tcon going bad looking at the photos. Measuring the voltages as per post #4 will confirm this.

[DoubleDD]

Re: Sony KDL40V4100-Dark Picture

hanks for the quick response from all.


Here's the voltage readings from the VGMA test points on the TCON Board

1 - .06
2 - .07
3 - .07
4 - .07
5 - .08
6 - .18
7 - .73
8 - 1.42
9 - 1.59
10 - 1.90
11 - 1.98
12 - 6.76
13 - 7.29
14 - 7.04
15 - 4.91
16 - 4.66
17 - 4.16
18 - 3.44
19 - 2.83
20 - .7
21 - .56
22 - .29

Do these voltage numbers look correct, or did I mess up?

Interestingly and possibly due to me being a novice repairman, when I touched the first VGMA test point 1, the picture on the screen instantly became very light with 11 double vertical bars on the screen. Wolf Blitzer's skin tone is no longer reddish but a ghostly white. Not sure if my testing toasted the TCON board or if it is just another issue with a failing TCON and AS15. Just to confirm the AS15 is part of the TCON board correct. Here's the new picture and the residual shadowing. As before any help or suggestions are appreciated. Sounds like I should replace the TCON board.

[paulstef]

Re: Sony KDL40V4100-Dark Picture

No, these voltages are not correct. Can you confirm the TCON board number and post a picture of it here, there seem to be different types for this TV. The gamma chip is on that board , yes. AS15 will be printed on it if it is this buffer they use. It's usually a small chip with pins on each side. Could be some other chip also.

[DoubleDD]

Re: Sony KDL40V4100-Dark Picture

Thanks or the super fast reply. The board is a T400HW01 V5, 40T02-C06.
I'm not an expert on multimeter testing so I set it on DC volts and received the readings above. They do look low compared to others in the forum, am I measuring incorrectly. And I do see the AS15-F chip on the right side.

[paulstef]

Re: Sony KDL40V4100-Dark Picture

If you measured the voltages correctly then yes, it is very likely the chip is toast.

You'll find them on eBay.

You will need hot air, a soldering iron and flux to replace this properly.

[DoubleDD]

Re: Sony KDL40V4100-Dark Picture

Really starting to rethink the Sony product line. this morning I turned on the Bravia had the same brightened picture with lines through the picture and the menu. Then the picture went completely, still have backlights and can see a slightly lighter bluish black screen when powered on. But I have no picture even using the flashlight test and the menu from the set no longer displays. Tried HDMI and external coax signal. Nothing.

[noledud]

Re: Sony KDL40V4100-Dark Picture

We have people in the UK who offer a repair service on ebay maybe worth a look if you cant do it your self

[DoubleDD]

Re: Sony KDL40V4100-Dark Picture

Ok, so I finally replaced the TCON board, still no picture. I get the glow from the backlamp and I get audio only through the RCA plug inlet only. A friend mentioned that if I disconnect the TCON and still have audio it indicates a bad TCON. Does this sound correct or is this indicative of a bad BU board. I checked the fuses on the BU for connectivity all look good.

[zomi]

Re: Sony KDL40V4100-Dark Picture

Check on the fuse
I have marked it for you
You should Have 12v
either side.

IF there is no 12V
I think you have blown a fuse on the main board

Will need pics of the main board.
Have had this happen when re fitting t cons on theses type on sony..

[Andrew F. Ali]

Re: Sony KDL40V4100-Dark Picture

Check on the fuse
I have marked it for you
You should Have 12v
either side.

IF there is no 12V
I think you have blown a fuse on the main board

Will need pics of the main board.
Have had this happen when re fitting t cons on theses type on sony..

Also check the flat cables and ensure you connected them properly. Replacing your original T-CON with a good one WOULD have fixed your problem. However, you could have bought a defective T-CON Bd also.

[budwich]

Re: Sony KDL40V4100-Dark Picture

Ok, so I finally replaced the TCON board, still no picture. I get the glow from the backlamp and I get audio only through the RCA plug inlet only. A friend mentioned that if I disconnect the TCON and still have audio it indicates a bad TCON. Does this sound correct or is this indicative of a bad BU board. I checked the fuses on the BU for connectivity all look good.

what does this mean? exactly which cables are you referring to / disconnecting?
if you disconnect all of the cables going from the tcon to panel, then you will get no picture. only do one at a time... what is the result?

[DoubleDD]

Re: Sony KDL40V4100-Dark Picture

Thanks Zomi, Andrew, Budwich

I am not getting 12V at either end of the fuse on the TCON board as marked up by Zomi. The flat cables all appear to be fitted correctly with no kinks or breaks. To answer Budwich, I was told to disconnect the flat cable between the Main Board and the TCON board, if I still has audio which I do, then it was indicative of a bad TCON board. But after checking the voltage at the fuse on the TCON it appears that the TCON is not receiving power. Advice on where to check the fuses on the Main board that feeds the TCON would be awesome, or any other advice of what to check next is very much appreciated. I have attached a photo of the main board A1506072C.

[DoubleDD]

Re: Sony KDL40V4100-Dark Picture

Also I find it odd that I only receive audio when using the antennae coaxial input on the main board, I tried the HDMI and RCA plugs no audio and obviously no video.

[Andrew F. Ali]

Re: Sony KDL40V4100-Dark Picture

I have never known a bad T-CON Bd to cause faulty audio. If you have no 12Vdc on either side of the T-CON fuse check the fuse for continuity and seek to determine if the 12Vdc is being produced at the Main Bd for T-CON power.

[DoubleDD]

Re: Sony KDL40V4100-Dark Picture

The fuse appears to be fine on the new TCON board, I have continuity on the fuse. It appears that as Zomi mentioned I have a blown fuse on the main board. I need advice on where to check the fuses and voltage output on the main board.

[zomi]

Re: Sony KDL40V4100-Dark Picture

I have marked the areas on the pic
check the fuses in this area
i cant make out from the pic which one is the fuse
but you have 2 in that area
please check those.

Also when the tcon is connected do you have 12v on that fuse on the tcon ?