Sony KD-70X690E. Started with reset loops.. then it got more complicated. I'm at wits end!

[phuzzyday]

First of all, thank you everyone who helps others in here! You guys are treasures! Please bear with me, this may be long. I have tried a LOT.

First, my wife said the TV was turning off and on. When cold it would be fine for several minutes, then it would start resetting.
I opened it up and noted there are two main lines coming out of the supply besides the backlight., The T-Con 12V line and the main 12V line.
TRIED 1 - I scoped power coming from Power Supply while it was all still connected. I noted that just before it reset, the 12V line going to the T-Con was going unstable and oscillating badly.
TRIED 2 - This resetting stuff happened to me before on a Sammy, and recapping the power supply fixed it. So I recapped whole power supply, aside from the 4 long gold ones laying down on the top of the board. I did test them out of circuit, and they came out great. Unfortunately, so did all the old ones I took out.. Problem remained, however the oscillation I saw on the scope seemed to go away. (Now I am second guessing whether I tried AC coupling it at this point and zooming in enough to see it...)
TRIED 3 - I unplugged the T-Con power cable, no change. I unplugged the backlight connector, no change.
TRIED 4 - I'm proud of this one... I intercepted the T-Com power lines from the power supply, and fed 12V into it from my bench supply. I interrupted all the T-Con lines on both connectors and connected them all to my supply. (They all had continuity on the power supply board anyhow.) Things got no better! Things got no worse either. All the other conductors were connected still.
TRIED 5 - I remelted all the solder points on the power supply board with flux and a touch of leaded solder on the bigger ones. No change.
Note: After I reproduced the problem lots of times while doing all this, I noticed that it would run less and less time when started cold.
TRIED 6 - Freeze spray! Long story short, I hit all three boards HARD in the end, and.. nothing changed!
TRIED 7 - I checked the current on the T-Con board, and the backlight. The T-Con was pulling 600 mA, and the backlight was at 400 mA. I don't know if these numbers are right.

So... I'm kind of at a loss right now. So if there are any geniuses in here, willing to help, Thank you in advance!

Phil D

[nomoresonys]

No genius at all but I'll try to help, are the expected voltages coming from powerboard, should be a label/legend nearby. Can you post some good clear pictures of each board and one of the whole back as to see how everything is connected. When you say recapped all, do you mean ALL or just the electrolytics?

[nomoresonys]

You probably already checked all the resistors, diodes and transistors on top of the board.

[nomoresonys]

Sonys are tough, haven't seen too many get fixed around here lately.

[EazyBone]

It will turn on for a few minutes when sitting correct? If this is the case.. Open the service menu and look and see what error is potentially tripping in the service menu. Get your camera ready to take a picture of it right when you get to it so that it doesn't shut off on you. This may give a clue.

And I agree Sony's are tough.. I would guess the back lights or the main board. If you have an LED tester not a bench supply then I would test them out of circuit with the power supply.

But shit, you never know when they Sony panel goes bad also lol. Damn Sony's.

Edit.. also check the BL error pin. Does it have voltage

[phuzzyday]

Thanks for the input guys! I forgot I posted in here for a day or two!

The expected voltages are coming from the power board. And yes, I have checked all of the components on top, Any that were 'weird' I pulled out of circuit. I will get those pictures. Actually, I have the top one now!
Easybone.. I attached the diagnostics screen. Is the backlight power derived from the T-Con 12V line? That might give me a connection between the wonky T-Con voltage I saw on the scope and this backlight error... I need to re-scope that voltage line to make sure maybe.

Note also - I have tried unplugging the T-Con AND Backlight connectors. Nothing changed, but unplugging those might cause the same error!! (Hmmm... It would happen immediately though. I haven't tried when it was cold...!) That might have caused some more errors on the service screen, but I know there was only one before, and it will certainly be the highest number of occurrence's!

And - As the stomach turns... Right after it started happening, I put it face down on our clean table, and it contacted the frame only. Then I put the stand back in, stood it up, and when I powered it back up... There was a line of pixels out vertical from the top down 3/4 towards the bottom, At about 75% of the way to the right. When I saw that, needless to say, I was pretty sick for a bit. I'm maintaining hope that I might be able to stuff something between the contact tape and the aluminum to put a bit of pressure against it. If it comes down to ordering a board or something I am going to try to address that before doing so. If I can't, I am going to ask myself if I REALLY want to put up with that line on there before I put up more cash. Nice huh?

I haven't checked the other pins on the connector which refer to status, etc, but I will tomorrow! I've been working on a '77 Thorens Turntable today. I'd take that era any day...

So Sony has a bad rep when it comes to repair??

[Davi.p]

rule out the main board, do the panel self test, run a cable from psb 12v to tcon fuse, detach MB and give current, if an BWRGB color test runs well endlessly, bad MB

[phuzzyday]

rule out the main board, do the panel self test, run a cable from psb 12v to tcon fuse, detach MB and give current, if an BWRGB color test runs well endlessly, bad MB

My friend Davi.p- you are obviously the kind of guy I need to talk to !! I am having trouble understanding your instructions though. I don't know where the 'T-Con Fuse' Point to connect to is! Also, How can I power up the power board with the MB detached? I am assuming I need the power board to run the backlight for this, so I don't think you mean a bench supply. I tried going from the 5V Stanbdby to the Power On, and the T-Con On, to trigger them, but no life. No damage either though! Thank you SO much for the tips! I'm almost there!

I also just popped the wide cable from the T-Con and turned it on, and all I got was a backlight with no image, and no change to the problem. (I thought that might trigger the test you speak of.)

[Davi.p]

Sorry, posted in a hurry, well, firstt i forgot is a Sony, so first we need to know how the psb (power supply board) outputs the voltages, i see the photo now, needed a double jumper TCon-ON - Power-On - 5VSB, in this way you enable Tcon12v-out on the respective connector, on the back you could solder a single wire (at least 0,5mmq thick , sorry i now metric system only) that goes to the fuse near the supply connector on the tcon, the fuse is usually white with gold plated terminals, if you would do a better job , best is to get spare wires from old bench PC with 1pin connector, or buy a bunch of "female jumper wires" from the net, detach completely the main board, and give current, in most of the cases the screen does an endless autotest black white red green blue full screen, if it works good > bad main board..

[phuzzyday]

Thanks for the reply! I use metric all the time, no worries! I have a well set up lab.
Let me see if I understand... Jumper the 5v-tcon on-Power on terminals. That power wire thing... Are you aware that there is a separate power cable direct from the power supply to the T-Con? Bottom of the board, closer to the right. I think the T-Com power to the mainboard might be for monitoring.. There is continuity between them anyhow, so the T-Con is getting power already from the power supply.
So I earlier removed the mainboard connectors, jumpered those 3 pins, and (with power still to the t-con), plugged it in. The power supply powers on, with a bit more noise than usual.
That might point to the... T-Con?? Interesting.
I think the signals from the mainboard to the power supply and back are pretty simple. If I monitor them when it's working, and when things go bad, I will probably learn something, perhaps I'll be able to see and reproduce a glitch that tells me where to go!

[bohaboha]

Hi where are all the pics nomoresonys asked for thanks

[Unspun01]

Before we get too far into the weeds with this TV, Does the TV reboot completely? or does the TV continue to operate WITH SOUND but a black screen?

And please be clear: When your TV stops working properly, is the screen black and completely without backlights? or is the screen black with no image but backlights are actually on? Your original post does not say.

The fact that you posted a screenshot of the self-check screen indicates your problem may not be a backlight. This may be a mainboard problem where TV mainboard works until it craps out.

If TV still plays sound from a video input or an app like Netflix while watching it, then I suspect a backlight LED or backlight power issue. Otherwise, if you have black screen and sound, can you verify with bright flashlight or lamp if you still have an image on screen just no backlight?

Here is a youtube video for a KD70X690E with a backlight issue and it shows a simple (but not so simple) fix removing a protection diode that can interfere with backlight:

https://www.youtube.com/watch?v=b-p1tZCeoh8


If that backlight tip is not helpful, then I also want to clarify if this an android smart TV?

Even though this is a KD-70X690E, this sounds similar to an issue that myself, nomoresonys, and others have experienced with the similar line of X690E Sony TVs in the XBR series - namely XBR-49X690E, XBR-55X690E, XBR-65X690E and XBR-75X690E. The TV will turn on, and you will hear a relaxing ambient "spa" music, but never does an image appear on screen.

Please refer to this other forum thread on the 49", 55", 65", 75" X690E models above:

https://www.badcaps.net/forum/troubl...00e-no-picture

The user Nick's Tvs seems to have lots of experience fixing the XBR series, so maybe he can offer some insights as to whether the KD-??X690E series has similar mainboard/tcon issues also?

[Davi.p]

Hi, by the first post i trend for a bad bga on main.board, but after the test of the panel, if nothing happens and no WBRGB test shows, i don't know, not the 100% of the panels supports this type of test, the more noise is probably a light loaded psb due to panel off, tcon half on, so not clear.. but if when it shuts off it doesn't blinks a 5 code error then 100% bad bga on MB

[nomoresonys]

Before we get too far into the weeds with this TV, Does the TV reboot completely? or does the TV continue to operate WITH SOUND but a black screen?

And please be clear: When your TV stops working properly, is the screen black and completely without backlights? or is the screen black with no image but backlights are actually on? Your original post does not say.

The fact that you posted a screenshot of the self-check screen indicates your problem may not be a backlight. This may be a mainboard problem where TV mainboard works until it craps out.

If TV still plays sound from a video input or an app like Netflix while watching it, then I suspect a backlight LED or backlight power issue. Otherwise, if you have black screen and sound, can you verify with bright flashlight or lamp if you still have an image on screen just no backlight?

Here is a youtube video for a KD70X690E with a backlight issue and it shows a simple (but not so simple) fix removing a protection diode that can interfere with backlight:

https://www.youtube.com/watch?v=b-p1tZCeoh8


If that backlight tip is not helpful, then I also want to clarify if this an android smart TV?

Even though this is a KD-70X690E, this sounds similar to an issue that myself, nomoresonys, and others have experienced with the similar line of X690E Sony TVs in the XBR series - namely XBR-49X690E, XBR-55X690E, XBR-65X690E and XBR-75X690E. The TV will turn on, and you will hear a relaxing ambient "spa" music, but never does an image appear on screen.

Please refer to this other forum thread on the 49", 55", 65", 75" X690E models above:

https://www.badcaps.net/forum/troubl...00e-no-picture

The user Nick's Tvs seems to have lots of experience fixing the XBR series, so maybe he can offer some insights as to whether the KD-??X690E series has similar mainboard/tcon issues also?

Oh crap, that xbr65x900c was a nightmare, was a donation but that's where the fun ended. worked fine for 3 days then got 6 blinks, tore it down=huge job, soo many tiny screws and of course a few refused to come out and had to more or less be drilled out and hidden screws too. Backlights were blinding bright all worked but still one could have been bad. first I blew up the powerboard which was probably ok, then started picking on the mainboard and messed it up. Threw a replacement powerboard at it which it did need after the first one blew up. I was intent on figuring out what was wrong. Decided that even if I managed to fix it there's no value there because the three days it did work, the picture was very crappy compared to well just about any old tv that wasn't edge lit. Sure I tried to calibrate it by my likes and the pro-calibrators from the usual sites. Picture was just horrendous. So common sense finally prevailed and I stopped. Thank you sony lol.

[KYBOSH]

So common sense finally prevailed and I stopped. Thank you sony lol. [/B]

You should have kept going... for science and experience. Dont stop unless it catches on fire!

[nomoresonys]

Lol, I would have but the damn mainboard is ridiculously high. Was my error, jumped in before I thoroughly understood the mainboard. That costly mistake made fixing it not worth the effort, plus I couldn't deal with the poor picture quality on that one. those era edge-lit tvs are the worse. Had a samsung edge-lit, same crappy picture. After a while you don't even have to look it up, just plug it in turn it on, picture not sharp and crisp? Yep it's edge lit.