Kdl-46s4100

[xZapx]

Hi all,

New to the forums and have done a bit of reading so far. Have a Sony Bravia KDL-46S4100 that I'm trying to troubleshoot to a repair point. It powers on and the backlight activates but there is no picture and no sound. I've never seen anything but the backlit black screen. Remote works to power the TV on and off.

I've done some probing on the boards to establish at least some type of functional status. The power board connections all appear to have voltages nominally close to their markings. I believe the 12V is something like 11.6 but guessing that's alright.

So my big question here revolves around panel faults vs A board faults (vs T-CON faults). I'm guessing if there is the classic panel problems you'd get some type of picture?

Are there any other tests I can run and would it be safe to say an A board swap should likely fix the set? Thanks in advance for any advice you might be able to give!

[dick_barton]

Re: Kdl-46s4100

Please can you supply clear photos of the circuit boards and their interconnections.
Also if you can list the voltages you have read alongside their legends would prove a good starting point.

[budm]

Re: Kdl-46s4100

Please can you supply clear photos of the circuit boards and their interconnections.
Also if you can list the voltages you have read alongside their legends would prove a good starting point.

+1. You can also check to find out if you do have 12VDC on both ends of the SMD fuse on the T-CON board.

[xZapx]

Re: Kdl-46s4100

Ok, starting out with the board pictures and I'll make a list of the measurements in the near future.

I checked the T-CON fuse and it shows a normal resistance of a few tenths of an ohm (not open). I'll also get voltage measurements just to be sure it isn't bad in some way only under load. I don't see bulged capacitors anywhere.

The A board appears to possibly be an earlier revision - 48.71H01.021

[budm]

Re: Kdl-46s4100

So you do have 12VDC at the SMD fuse on the T-CON board?
If you do, then try having the ribbon cable between the T-CON and the LCD panel connected one at a time to see what you get on the screen.

[Diah]

Re: Kdl-46s4100

Ok, starting out with the board pictures and I'll make a list of the measurements in the near future.

I checked the T-CON fuse and it shows a normal resistance of

check yours Photo No 3 . the left side ribbon cable not really in it place.. it should more forward inside the T-CON socket .... !!!!

[budm]

Re: Kdl-46s4100

Hmm, someone else worked on the TV before you got this TV?

[Diah]

Re: Kdl-46s4100

of sure he was but he did missed it. its look there S/C at the ribbon as the rest down to the Panel as its not really straight

[budm]

Re: Kdl-46s4100

He must have disconnected those cables when the metal shield for the T-CON is removed and did not put them back on correctly.
Details, details, details.

[Diah]

Re: Kdl-46s4100

exactly. this why photo very important to show what users did and he didn't write it down

[xZapx]

Re: Kdl-46s4100

Sorry for the confusion - I haphazardly reattached the cable just to take the photo after removing the shield. I figured that a picture with shield would be rather useless. I noticed the mistake and put it back in place.

There is power (11.62VDC) at the T-CON fuse.

Disconnecting the ribbon on the left results in a picture on the left side of the screen - "No Program Title Available" dialogue box message on a black screen. The other half of the screen is white.

Disconnecting the ribbon on the right side results in a screen that is all black. Does this mean that the LCD panel should be OK since I saw half a picture? Any thoughts on this result?

Will be checking voltages and also post those once I have them.

[xZapx]

Re: Kdl-46s4100

CN301
15V - 15.67 V
SGND - 0V
6.5 V - 7.17 V
3.3 V - 3.39 V
12 V - 11.64 V

CN302
3.3 VSB - 3.29 V
PS-ON - 0.02 V

CN303
BL-DIM - 3.0 V

AC Input 122.1 VAC

Any others that would be of use?

[Electronic Handyman]

Re: Kdl-46s4100

Those KDL Sony models are famous for T-con board faults and from your ribbon test it sure seems like yours has a bad t-con board too.

[budm]

Re: Kdl-46s4100

Sorry for the confusion - I haphazardly reattached the cable just to take the photo after removing the shield. I figured that a picture with shield would be rather useless. I noticed the mistake and put it back in place.

There is power (11.62VDC) at the T-CON fuse.

Disconnecting the ribbon on the left results in a picture on the left side of the screen - "No Program Title Available" dialogue box message on a black screen. The other half of the screen is white.

Disconnecting the ribbon on the right side results in a screen that is all black. Does this mean that the LCD panel should be OK since I saw half a picture? Any thoughts on this result?

Will be checking voltages and also post those once I have them.

You have bad panel.

[xZapx]

Re: Kdl-46s4100

Hmm - so I've got two possibly conflicting answers here. Is there anything further I can do to determine what is going on for certain?

[budm]

Re: Kdl-46s4100

You can try new T-CON if you want.
Or you take a lot dcv Voltage test points such as VGH, VGL, VDD, VCC, ETC on the T-CON board when you only have one ribbon cable connected and get half the picture on the screen, and then take the reading again when BOTH ribbon cables are connected to the screen.

[xZapx]

Re: Kdl-46s4100

Would be glad to run through the test points if that helps paint a better picture. Are those points marked as such on the T-CON or do I need a chart that correlates TPx type labels to those voltages?

[Diah]

Re: Kdl-46s4100

since you had took out the ribbon cable left side and picture go on on the half screen, i suggest you to take the ribbon out and inspect it with Magnifier, one time wrong seated enough to destroy the gold print pins, you may find curved or shorted , after you are sure of them ... go forward to points measurements

[dick_barton]

Re: Kdl-46s4100

Once again I have to ask are you flipping the black part of the flat cable connector up and towards the Tcon board to connect/disconnect the flat cables or just pushing them in and out?

I agree with Diah. Use a magnifying glass and check the gold contacts for damage which is easily done.

If the gold contacts are fine and not damaged in any way then I go with Budm's conclusion of faulty panel.

[xZapx]

Re: Kdl-46s4100

Definitely flipping the black part on the connectors - will check the contacts close up for damage.

So with two weigh-ins for faulty panel - is the panel comprised of two separate sections, since I saw half of it working? Also, if I did see that functionality does that mean the other circuit boards would be good as parts for repairing another unit?