Sony Bravia 40" LCD Model KDL40s4100

[jimb0b]

Picked up a non-working Sony Bravia 40" LCD Model KDL40S4100 today FOC. Cleaned it up, checked for physical damage, and then powered it up: power light came on, snow on screen for a couple of seconds followed by blank screen and standby light flashing twice. I haven't opened it up yet but wondering if anyone has any ideas on the best way to short circuit (!!!) the fault finding process. Thanks in advance. This is my first LCD TV although I have done a few computer monitors in the past. And this is my first post here so take pity on me

[budm]

Re: Sony Bravia 40" LCD Model KDL40s4100

Service manual:

The bad part for this model: from page 11 of the service manual

IMPORTANT:
The units in this manual DO NOT contain a self-diagnostic function. If an error occurs, the TV will not stay on. It is our
is required for this set, the technician should bring both the A Board and the G Board to the customer location.

[jimb0b]

Re: Sony Bravia 40" LCD Model KDL40s4100

.....
The bad part for this model: from page 11 of the service manual

IMPORTANT:
The units in this manual DO NOT contain a self-diagnostic function. If an error occurs, the TV will not stay on. It is our
is required for this set, the technician should bring both the A Board and the G Board to the customer location.

Yes, I saw that unfortunately. When I first searched, I came across references to the self-diagnostic function of similar models (Sony, 40", LCD with CCFL) which suggested that two flashes of the Standby LED was a inverter board problem. So I thought, great - that will be an easy replacement!

Oh well, I guess I'll know more when I open her up I've never worked on anything that needs this much bench space before.

[tom66]

Re: Sony Bravia 40" LCD Model KDL40s4100

I believe me/Sienoki have this same model with bust screen, but all parts working.

[jimb0b]

Re: Sony Bravia 40" LCD Model KDL40s4100

Are you referring to Sienoki who posts on this site?

[tom66]

Re: Sony Bravia 40" LCD Model KDL40s4100

Yes. I can't remember if it's "S" or "W" we've got, but the boards may be good for either.

[jimb0b]

Re: Sony Bravia 40" LCD Model KDL40s4100

So finally got some time to take the back off and start looking around. No obvious capacitor issues or burned out components or previous repair attempts. I'm going to do some voltage and continuity checks shortly and check the inverter board. In the meanwhile, here are a few "interior" shots.

[Village Electronics]

Re: Sony Bravia 40" LCD Model KDL40s4100

Picked up a non-working Sony Bravia 40" LCD Model KDL40S4100 today FOC. Cleaned it up, checked for physical damage, and then powered it up: power light came on, snow on screen for a couple of seconds followed by blank screen and standby light flashing twice. I haven't opened it up yet but wondering if anyone has any ideas on the best way to short circuit (!!!) the fault finding process. Thanks in advance. This is my first LCD TV although I have done a few computer monitors in the past. And this is my first post here so take pity on me

My guess is that you have a bad ccfl. That is inside the LCD panel itself. They can be changed but it is not easy.

[budm]

Re: Sony Bravia 40" LCD Model KDL40s4100

I would remove the balancer board and look real close at the sockets where the board is attached to the lamps, see if the black sockets have any sign of over heat or blister, look and clean the fingers of the board also, insert the board back in and see if the lamp will stay on.

[jimb0b]

Re: Sony Bravia 40" LCD Model KDL40s4100

I checked the voltages on the test points behind the transformers and they ranged from 0.1V to 0.4V except one which was 9.1V (see picture). So I figure I have the problem. The next question: is it the transformer or the ccfl? Any ideas on how to figure that out?

[jimb0b]

Re: Sony Bravia 40" LCD Model KDL40s4100

Success! I removed the transformer which showed the abnormal voltage, soldered in a jumper and up she came! Using OTA signal, it picked up 12 high def stations immediately. Now all I need to do is find a remote for it.

BTW, the efffect of removing that ccfl is practically nil. With any picture on the screen, you absolutely cannot see the difference. When there is a blank screen, it can be noticed from acute angles and then only if it is mentioned.

Here are pics of the final result (Craig Ferguson interviewing Susan Sarandon tonight) and a picture of the repair.

Tks everyone for your help and advice.

[budm]

Re: Sony Bravia 40" LCD Model KDL40s4100

Great job locating the cause of the problem. By the way, what resistance reading on the transformer you removed compared to the other transformer? It looks like the transformers are hooked up in series with each other.
Other person on the forum had the bad connection problem with the PCB sockets so you may also want to keep an eye on that. I will take some resistance reading of spare SONY balancer board's transformers.

[tom66]

Re: Sony Bravia 40" LCD Model KDL40s4100

Norcal715 with similar problem on a Samsung: http://www.youtube.com/watch?v=oE6K4xBVweA&feature=plcp

I think he diagnosed it as a failed CCFL, not transformer.

[jimb0b]

Re: Sony Bravia 40" LCD Model KDL40s4100

Great job locating the cause of the problem. By the way, what resistance reading on the transformer you removed compared to the other transformer? It looks like the transformers are hooked up in series with each other.
Other person on the forum had the bad connection problem with the PCB sockets so you may also want to keep an eye on that. I will take some resistance reading of spare SONY balancer board's transformers.

Thanks!
As I had no way to decide whether it was the transformer or the tube, I decided to pull the transformer to see if a) it would work at all and b) everything else is working. So far, everything else seems fine although I don't have a remote for it so it is a PITA to change settings etc. So that is the next job: find a remote Sony RM-YD025 or compatible model.

[jimb0b]

Re: Sony Bravia 40" LCD Model KDL40s4100

Norcal715 ...... http://www.youtube.com/watch?v=oE6K4xBVweA&feature=plcp

It was this video which helped me find the problem. I added a "like" and a comment.

[budm]

Re: Sony Bravia 40" LCD Model KDL40s4100

Ah, so the lamp is bad, not the transformer. Thanks for the link to the YouTube, learning something every day, 1200 hours and the lamp already failed, sad.

[jimb0b]

Re: Sony Bravia 40" LCD Model KDL40s4100

Ah, so the lamp is bad, not the transformer. Thanks for the link to the YouTube, learning something every day, 1200 hours and the lamp already failed, sad.

I don't for sure whether it was the ccfl or the transformer. Removing the transformer covered both possibilities.

Is it possible to remove and replace a ccfl?

[RenoRJ]

Re: Sony Bravia 40" LCD Model KDL40s4100

I had the same problem with my Sony KDL-40S4100. Go green then a couple seconds later Standby light would blink twice.

I unplugged the main connector on the inverter board and left the smaller connector on the bottom connected. The tv came up and stayed on no pic just sound.
I pulled the inverter board off very carefully using a plastic wedge tool on the outer side. I found that the third tube up from the bottom connection was broken off. At first I thought why would a circuit that is not drawing anything cause a shutdown. I checked all of the coils went back to that one and yep it spiked. I took a look at the video on U tube.pulled the board and removed the coil and jumped out the 2 outer pins.

Picture came up and I cannot see the missing tube.

Thanks for the info and the link to the video, it helped out a lot.

RJ