Big Black Bravia

[Longbolt]

Hello, All
Sorry, I speak not so good English.
I found good information on badcaps so I decided to post here !

I found on the street a thrown Sony Bravia KLV-S40A10E : )

put it on my bicycle and took it home, and it was powering on with black lcd panel screen but backlight on and green led, few minutes after the backlight disappeared and it was refusing to power on, when the button power pressed, the red light disappears but no green one and no relay click : (

I opened it for bad caps and tried to power the PSU by connecting the STBY 5V with POWER ON, as I do width computers PSU; it wake up, so I was able to check the voltages on the power board. All voltages were there but two of them are at 19V instead of 17.5V regulated. I don't know if this difference of 1.5V may be the problem.
Also I have all the voltages going from the PSU to the GE2 board but from the GE2 to the main board it is missing 2 x 5V and 1 x 3.3V and no voltages on the small slot from GE2 to main.
As I learned from this forum is the main board that sends the signal to PSU to wake up, performs some checks and starts to do the job, if the incoming voltages are bad it shuts the PSU down. After struggling with the service manual I understand, I may be wrong that is happening inside the video processor board (BE board) which sends the wake up signal via the main board. In my case no signal is sent to PSU except to the BE board and the red led (no error codes).

In some words I was very happy to see this big TV in that dark street waiting for me, but now I see 4 big boards with thousands of micro components laying on my table, not so romantic any more.
I got the service manual from www.eserviceinfo.com. It is a good address to save.
Here is the picture of it insides.
I will be thankful If you can give me any advise witch part should I change or check. Would like to narrower the problem, but I am beginner with electronics ☺

[Dgtech]

Re: Big Black Bravia

If you can get in closer with your camera, I think I can see burn marks on a board. Please take closer pictures of the light blue board.

[Longbolt]

Re: Big Black Bravia

If you can get in closer with your camera, I think I can see burn marks on a board. Please take closer pictures of the light blue board.

Hi, is no burn really, warm air deposed dust with the time. I agree on the 1st picture it looks scary!

[Longbolt]

Re: Big Black Bravia

When I press the power button on, there no signal send to the pin power-on.
When I send +3V on this pin the power board wakes up, but no backlight
There is 5V stby on main and video processor board.
I was suspecting the board between the PSU and main board, the GE2 (power supply regulator) because voltages were missing, so I ordered a used one from e-bay but nothing changed.

I marked with green the voltages I can read, with red those I do not have and yellow witch are not correct 19V instead of 17.5V
Are those boards bad, can they be bad the same way?

[momaka]

Re: Big Black Bravia

If you have the service manual, see if tells you which board is responsible for the logic control, then take a picture of that board and post it here.
Alternatively, post pictures of each board. That way we can point out all of the voltage regulators that may need to be checked. The abnormality in voltages you got may be caused by an overload or an underload due to a bad regulator somewhere.

[Longbolt]

Re: Big Black Bravia

Sorry the regulator boards are not bad the same way as I stated in my last post.
On the “new one” from e-bay a +9V pin is a alive compared to the my old!
The auction was saying “checked and taken from a working set”; shame for the TV!
Now - Should I stay or should I go?
With my little knowledge. But I'm fascinated looking at the schematics on the service manual, even thow is sounds like going
on a Japanese forum and trying to read! Anyhow I tried to be logic.

The history and situation;
1- The LCD died first but power, inverter and lamps were OK.
2- The power “died” refusing to start. But I can wake it up.
3- The Power Supply Regulator seems NOT OK but at this point I'm more interested by the +5V Stby which is all around
The Power Supply Regulator will be involved if by pressing POWER the PSU starts and shuts down (is my theory)
The man who sold me this Power Supply Regulator said;

“On the a12 model we have a lot of problems with diodes in the power supply giving this exact fault.
D6904 standby 5v supply (secondary)
D6903 d6905 r6304 r6305. (primary side of power supply)
Change d6903 d6905 even if they check ok as they break down under load. “

So I did but nothing changed.
Then I decided to fix me a start point witch was Who sends that wake UP signal?
It certainly not the Power Supply Regulator and the thing is certainly not drawing a lot of amps.
On the A2E4 board there is a little circuit that I called “Start” in the attachments below. The pen shows where the circuit is.
I thought that can be a start point for me.
The black arrow PSW MAIN lead to the BE board were the Power button connects but there are empty places for resistors and the end is connected to nothing!
How this PSU is waken up ?


A2E4 (Analogue Tuner, Audio Amp, Chroma Decoder, AV Switch, Scarts, YUV Input)
BE (Video Processor, PC Input)
G3 (Power Supply)
GE2 (Power Supply Regulator)

[Longbolt]

Re: Big Black Bravia

I see also three others ways to proceed:

1- To go to the nearest bridge with my little daughter and let the TV fly! How exiting it will be!
2- To try to make a 40” funky table that lights up in the night, if I can make the lamps work
3 – To sell it to someone more experienced

But I'll wait for some advices first

[Longbolt]

Re: Big Black Bravia

Right, momaka, the regulator issue lead me to see that most of the output voltages on the regulator board are driven on and off by the big A2E4 board.
So let's suppose those are OK (at least one of the two I have now : )
The 17.5V that I have at 19V are regulated on the PSU.

I checked again with the multimeter where PSW MAIN and POWER-ON lead, and found pair of transistors on the back side (on the BE board) conectet to stby3.3V rail, followed the service manual Power is triggereg from pin 67 on main processor. I like this number!
I also know from random voltage checks from the service slot that very exact 3.30V are generated on that board from the stby 5.00V.
But there are few thinks I understand, is getting too wired, the service manual is a fantastic tool but not for me yet! I suppose is stupid of me to want to keep on with those little components.

Professionals I suppose do not follow conductive paths with a multimeter for too long but make some kind of good decision wich board to change.
I also tried to do like that but…. no blinking lights!

At least now I have the brain washed by the TV's backside!

[dumpystig]

Re: Big Black Bravia

How the f**k did you manage to carry this on your bicycle???

[Longbolt]

Re: Big Black Bravia

How the f**k did you manage to carry this on your bicycle???

The white one

[dumpystig]

Re: Big Black Bravia

HAHAHA you gota be havin me on...

[tom66]

Re: Big Black Bravia

So are none of the capacitors bulging on the power supply?

Even if they are not bulging, it might be a good idea to replace them.

[momaka]

Re: Big Black Bravia

So are none of the capacitors bulging on the power supply?

Even if they are not bulging, it might be a good idea to replace them.

I doubt the caps are the problem. These TVs do run hot, but not hot enough to kill Japanese caps. From the pics, all I see is Rubycon, Nichicon, and Chemicon.
Would be very surprised if a recap fixed the issue. I guess it's worth a try, though - well maybe just the PSU. It's too much work to recap all of the boards.
This is one of the places where an ESR meter comes handy. But even with that, it will still take quite a bit of time to check every cap.

the regulator issue lead me to see that most of the output voltages on the regulator board are driven on and off by the big A2E4 board.

Interesting.
I just downloaded the schematic and will see what I can find. This is quite a bit over my skill level, but let's just hope 2 minds will work better than 1 .

[Longbolt]

Re: Big Black Bravia

The top of all caps looks even concave.
I appreciate your replays, all ideas are welcome.
I took the liberty to compare the circuit to a car;
if I have battery (the 5Vstby) to engage the starter (the relay), but I don't hear the starter running, why should I suppose that my engine is broken or that I have no gasoline.
And it's not because I see light on the board that means I have enough battery to run the starter
On the other hand I rarely shout at bad drivers because I never know how tall they are before they come out!
But if I want to know how tall they are I have to shout at them before I decide to run…
same should be for the logic board, no?

I just downloaded the schematic and will see what I can find. This is quite a bit over my skill level, but let's just hope 2 minds will work better than 1 .

Thanks a lot momaka. As you can see above my mind is not goin far with electronics

[momaka]

Re: Big Black Bravia

Okay, after a bit of looking at the service manual, at one point or another I came to ask pretty much the same questions as you - namely, which IC/board are responsible for turning on power to the TV. After a bit more analyzing, this is what I came up with so far:

1) When the power is switched on from the remote or TV button, one of the ICs (I'm thinking IC8503 and/or IC8500 on A2E4 board) sends a signal to the GE2 board to turn on all of the regulators (IC8800, IC8802, IC8803, IC8810, IC8805).
2) Once all of the regulated voltages are running, DC POWER (block diagram name)/DC ALERT (schematic name) comes up and allows PSW_MAIN to go high, which in turn sets POWER ON to high.
3) This in turn causes the PSU (G3 board) to turn on. Then, AC OFF DET goes low (or high?) and enables the main microprocessor IC1003 (pin 67) on the BE board as well as a number of other things such as SWITCH OFF MUTING (block diagram name on A2E4), HEADPHONE MUTE (again block diagram name), STEREO AMP IC7809, and triggers BACKLIGHT on BE board and LCD.
4) TV runs happily?

All of the above is just a theory, though, and I still have a few questions unanswered.

So for starters, I'd like to know all of the voltages coming out of the PSU (G3 board) on CN6200 and CN6201. However, measure the voltages with the PSU disconnected from all of the other boards. Do NOT force the PSU to turn on for this - just plug it in the wall and measure the voltages on CN6200 and CN6201. I'm particularly interested in AC OFF DET.

After this, repeat same experiment as above, except this time connect the GE2 board to the G3 board, but disconnect everything else from the GE2 board. On GE2 board, measure voltages on pins 6, 7, and 9 of CN8802, and everything on CN8801.

Let me know what values you get. I have about a page worth of notes but need to double-check my assumptions on some of the stuff.

[Longbolt]

Re: Big Black Bravia

You have gone far with it !!! The circuit only of these 3 boards printed to A4 scale can cover 10.2 square foot.
I will try again with the PDF to night so I can better follow what you already know. I feel lucky
I checked the connectors, CN6200 & CN6201 on stby,
1st with everything disconnected and
2nd just one side of GE2 connected to PSU
I have the same readings in both cases;
CN6200 - 0V on all pins
CN6201 – 1.35V on AC OFF DET

On the CN8802
Pins 6, 7, and 9 are at 0
(if I understood you right, is when those are not connected to the A2E4, if they are; 0.55V on pin 6, on 7 and 9 almost 0V)

On the CN8801 every pin is at 0V

*Concerning the reg.17.5V that are at 19V I saw a over voltage protection on the BE board left side on page 44.

[Longbolt]

Re: Big Black Bravia

I have a small 10MHz crt oscilloscope if it can help somewhere. Tryed multimeter on 67th pressing power on... no hope.

[Longbolt]

Re: Big Black Bravia

I feel like a flywheel diode.
Switching between 4 windows of the same file, getting confused when switching between diagram and schematics and still around pin 67 and Q7419, Q8490; Q7415 and Q7416
Why on page 39 pin 67 seems to be connected to 3.3V stby terminal when I checked with the meter there was nobody.
I think that I understand something going to next window, question, goin back and so on.
And all this produces dumped oscillations inside my head, which I hope is positive.
Tomorrow I'll make a try with pen and paper.

[momaka]

Re: Big Black Bravia

CN6200 - 0V on all pins

Aha! So my first assumption about how the TV powers on is not entirely right. New assumption:
1) When the power is switched on from the remote or TV button, one of the ICs (I'm thinking MAIN MICROPROCESSOR this time) turns on the PSU (G3) by pulling POWER_ON high.
2) PSU turns on and sends voltages to the regulator board, GE2. AC OFF DET also goes low (or high?), thus letting various ICs know that power is present.
3) PSW DIG, PSW SW, and PSW PANEL 5V go high (or low?) enabling the regulators on the GE2 board to produce the proper voltages
4) Proper voltages are checked, and if correct, BACKLIGHT is turned on and TV switches on.

With these assumptions, I now have the following questions:

1. How are you turning on the TV - are you using the remote or the buttons somewhere on the side of the TV?
2. Can the TV be turned on from those buttons at all? If so, do you know what board they connect to?
3. Otherwise, do you know which board has the IR sensor for the remote?

Basically, I'm trying to establish which IC or ICs is/are responsible for turning on the TV or at least get an idea. I'm thinking IC1003, the MAIN MICROPROCESSOR on the BE board.

Originally, I thought it was the PORT EXPANDER ICs, IC8500 and IC8503 on the A2E4 board since they seem to be involved with PSW SW, and PSW DIG and these control voltage regulators on the GE2 board.

However, I now see 2 new possible inputs - KEY and KEY2. I *think* these are connected to the buttons on the TV. KEY and KEY2 are located on CN1007 of the BE board and go out to CN9802 on the H1E board (refer to block diagram of BE board). KEY and KEY2 also seem to be connected to the STBY2.5V (through 1 kOhm resistors R1031 and R1033) and then go to pins 24 and 27 on IC1003, the MAIN MICROPROCESSOR.

KEY also seems to be involved with IC7402, PORT EXPANDER, and this IC is directly connected to PB_FAIL, PA_FAIL, POWER/RESERVE_LED, BACKLIGHT, ON_TIMER, and PC_V_DET. It's also connected to 5vsb, so it's probably important.

So, do you know what the H1E board does and where it is located?

Why on page 39 pin 67 seems to be connected to 3.3V stby terminal when I checked with the meter there was nobody.

Pin 67 is directly connected to POWER_AV. STBY3.3V connects to pin 67 through a 4.7 kOhm resistor, R7549, so that's why you might not see voltage there (perhaps IC1003 is pulling it low until power is enabled). There should be 3.3v on one side of R7549, though. If not, then that might be a problem.

I have a small 10MHz crt oscilloscope if it can help somewhere.

Maybe you can Check POWER_AV with your oscilloscope, just to see if you get any spikes. A multimeter cannot check if the voltage spikes quickly.

And all this produces dumped oscillations inside my head, which I hope is positive.

Same here.
Just think of it as a hard puzzle or an exercise for your mind though. In the end of the day, if you solve it, you might get a working TV - instant reward .

[Longbolt]

Re: Big Black Bravia

Same here.
Just think of it as a hard puzzle or an exercise for your mind though. In the end of the day, if you solve it, you might get a working TV - instant reward .

I have never dreamed that I can fix that kind of thing on my own but I consider that I'm already watching one of the most exiting thrillers I ever saw on a TV

H1E is the buttons circuit, the TV can be turned on from those buttons.I do not have the remote.
H3 is the IR sensor board.


I have tried in the beginning to understand what H1E circuit does but I can't , it probably brings to ground the 2.5V on pin 24.
I do have 2.48V on pin 24
KEY is connected to the button Power ON/OFF

Yes, KEY leads to a port PORT EXPANDER IC 7402 also to pin 24 on Main processor and REAL TIME CLOCK IC1007.

IC7402 have to do with the Backlight and POWER/RESERVE_LED. Key signal seems to be controlled by IC7402 via Q7420 but here agian I regret to do not understand.

It's really easy to find the word KEY inside the PDF by pressing Ctrl+F, for me it's getting complicated afterwards.

When I press power button a red light lights on ant if I press it again it goes off. I read 2.48V on pin 24 in both cases.

I can try to know if the led that lites is the POWER/RESERVE_LED or the stby one. Ideally pin 24 (key) drives pin 67 (power) and the main processor is very ill.