Sony XBR-75X800G - Android start up only and dark blue screen

[NolesFan]

its much likely Main Boards... but because you have dark blue picture, you need to testing the screen as standalone, if every things went correct then replacing MB.. you will not able to repair the boards. as its just ONE Soc ,
to do screen standalone test ..
disconnect the MB from PSU
disconnect the LVDS between T-CON & MB from T-con side
on the socket of the PSU, you need to jumper
Pin 5 STBY_3.3V to PIN 9 Power_ON & pin 7 BL_ON & pin 26 T-CON_ON check the pins No. you have print chart on the boards... it may my memories went weak

take 12V from the pin 25 T-CON VCC and put it on the F fuse on the T-con
put it in wall and check what you will have on the screen..

Note if you are not sure by pins name or No... use 1KR when you do the jumpers to avoid any damage to PSU in case you did wrong at pins order

Note 2 you can do hard reset from plug it out from wall . press joystick and push down then plug in wall leave the push only when the front LED change from white to green

Well i tried this with the new jumpers I got and the TV doesnt respond. When I plug it into the wall, I hear the initial click of the PSB but the remote or the joystick does nothing as far as turning on the TV. Im guessing its my connections with the jumper? Because as soon as I pull the jumpers off and plug the PSB to the MB, the TV comes on.

[Davi.p]

it seems a common problem at the lcd panel, alternate short to a condenser, must do the screen self rest.. remove lvds cable from MB, jumper a 12v from PSB to tcon fuse, turn on and see full screen colours for the time to eliminate doubts..

[NolesFan]

And now at this point, I can turn the TV and it will show normal picture, work for a few hours then go dark blue. I can shut off the TV for a little while, turn it back on and its a normal picture again. Leave it on a few hours and itll go back to dark blue.

[NolesFan]

nomoresonys Ok, Ill check that along with #14 post. But since I wrote and you wrote, I went out to TV, still have it powered on, unplugged harness at PSB to the MB and plugged it back it, the TV booted up with Android screen and is now back to Home.

[nomoresonys]

Also if you have not yet, make sure you don't have any bad solder joints on powerboard, just search for images of bad solder joints if needed.

[nomoresonys]

Do that wiggle with the harness, starting to think if you get a good picture after messing with it sometimes, you may have a wire in it that only gets connection sometimes, you can test continuity of each wire form end to end with meter, want to be careful not to stretch out the ends of connectors with meter leads. I use stripped bread ties sometimes to poke in the ends to make connection for testing, then wiggle the harness, each wire should maintain continuity if one doesn't then it's a bad/broken wire.

[NolesFan]

Thank you vinceroger69

So I ordered new jump wires that are smaller on the base to allow less interference, but in the meantime, I was playing around with the harnesses again and the picture came back on. It was that was for 2 straight days. I went to move the TV ( its standing on its base ) and when I shifted the TV and set it down, i lost the picture, but the sound to what I had playing on Youtube is still playing. Is that type of issue leading anyone to believe its definitely the MB or I still need to wait to get the jumpers and run the test in post #14? Thanks

[vinceroger69]

1kr diah means 1k resistors used for jumping pin to pin

[NolesFan]

Diah

I bought some pin jumpers from Amazon to link up the 4 pins you mentioned ( 5 - 7 - 9 - 26 ) but they are too loose. What type of jump wires are you using to test things? When I pull the harness off the PSB, Im left with male ends. I cant get a wire to sit there, alligator clips are too big, and like mentioned, I bought female test ends to push on but they are too big for male pin and just fall off. I tried leaving the harness plug in on PSB and using male pins, but when I did the asked configuration, the TV wouldnt power on, so I figured I wasnt getting a good connection with the pin set I bought.

Also you mention 1KR, Im dont know what that refers to? I am able to figure out which is which because I can see on the board the 1 and 2 respectively designating which row is odd or even.

Any help with names of jump wires or links you can provide to purchase a good set of test leads would be awesome. Or if you can point me in the direction of what to use that works best, that would be awesome also. I really appreciate any help you can give in the matter.

If when I get this configuration all correct and I do get an image on screen, then Im guessing its the MB that is what is wrong?

[nomoresonys]

Don't we all know by now that Europe has 220v and North America is 120v. Been that way for a very long time.

[Davi.p]

In USA things are very different than Italy.. here there are professionals that uses 5$ testers (very bad) and there there are absolutely beginners with 100$ testers.. very strange the world..

plus here a 75" bad tv but integer needs around 200/250$..

[NolesFan]

No, you guys were right, the metering was only ready 1 leg with the way I had it set. Correctly now metering both legs and I have 121.7. Sorry for the confusing on my part.

So now I with the correct voltage entering, I will run thru the tests you guys suggested. I appreciate the patience.

[Davi.p]

So i was NOT right.. the wall outlet is not the culprit but maybe the house cabling yes (??).. seems as a cable somewhere has a clamp, maybe due to oxidation, that when the tv is standby or cold the current is enough but when that cable heats the voltage drops.. i don't know how long is that extension cord but if is possibile it can be attached some way directly to electrical breaker for a test..

anyway due to the fact the tv is sold as bad, the answer could be inside it, so the huge loss must produce heat, when tv starts to have problem must feel that heat precisely, or since the drop is immediate the heat also can be felt immediately..

[nomoresonys]

Seems like the power cord is ok, can you explain exactly where and how you are measuring 64, how is meter set and where are you putting both probes?

[NolesFan]

Had the TV off all day, came home and was still reading 66.7. Wall outlet reads 123. If I plug the cord in to the outlet, but leave it out enough to get my probes on it, its reads 121. To satisfy Davi, I went to another outlet across the house, metered it: 121. Plugged in an extension cord, metered it: 121. Plugged tv to said extension cord, metered harness plug-in: 64.7, metered main fuse on PB: 64.7.

Well seems Davi was right though. After metering things, I left the TV on and about 10 minutes later, it reverted back to the dark blue screen. Sound plays fine, though this time, I can use the remote to talk to tv and it talks back, when I press the presets on the remote the picture changes in brightness then returns to the dark blue. So Im assuming go back to original testing as described before the "fix" happened, but the question now is, will i get accurate reading at the terminals if I dont have 120 entering the TV?

[nomoresonys]

Anyone paying attention would have read in post #22, that there is 120 v at the wall outlet and nobody needs to carry a tv to another outlet when an extension cord can be used.

[Davi.p]

You have a Fluke and you are not able to use it? Strange.. the power cord has surely no loss, but a test of it with ohm mode cannot let loose huge time.. don't waste time/money with a new cable, this is ridicolous.. a simple check is enough... "IF"" it's ok.. no.. scince it is ok the.main suspect is a bad wiring of wall plug, have you transferred the monster tv to another place and checked it? I suppose no since the size of it..

[NolesFan]

Glad to hear it, must have been a bad connection, sometimes it just takes cleaning or unpulg and replug a few times to get it working, curious if the voltage at powercord was still less than 120.

Well tv has run 24 hours so far. Just shut it down, Ill see tomorrow if it powers on. The voltage though was scary, at the connector and fuse, with a Fluke and a Klein 66.8 and 66.7volts. Curious if the lessening of the voltage as time goes on was a reason for shut down? Physically there is nothing wrong with cord, Id like to think buying a new cord would change, but ? Suppose I could always make a new test cord and try that first.

[Davi.p]

Don't think you have solved, i never seen so a stupid "repair" (well, it repaired itself), so the fault will come back.. also power kcord discourse is out of reason, with 26v at many amps you would have hot melting cable (200+W dissipating..)

[nomoresonys]

i mentioned yours eMMC Data in tact and yours melody first install... if the user don't know like David. keep silent other wise all TV will be in rubbish

You are correct sir, I would rather be the last one with the solution than be the first one to jump in with pure guess and speculation. Why drag someone down the wrong path when simple testing can determine the issue.