Sony xbr-75x900f 6 red blink

[Diah]

Re: Sony xbr-75x900f 6 red blink

i dont believe on seller what he say.... its make no sense at all... 11 & 12 are same as 10 & 9 no stupid manufacture let 2 strips different from others..

look on the 12 Left and the other 12 Right.... are there LED mounted in reserve way... if NO... then yours strips for 11 % 12 not correct or need to test the points of 11 & 12 on LED driver boards as R to chassis and compare them with 10 & 9... of course the ribbon cable should be disconnected from the boards at testing

[EazyBone]

Re: Sony xbr-75x900f 6 red blink

So the cycle goes this. I have tester on bl err pin. I plug in TV. Bl err goes to .65 volts for about 5 seconds (without touching anything) then drops to zero. I hit the power button, bl err goes from zero to .65 volts. One of the power supplies clicks and then goes to 3.3volts. All other voltages are correct. The backlights never turn on or even flash ever. The LD psu never supplies voltages to the LED driver board ever. None of this ever changes no matter what cables I disconnect. One at a time bl cable disconnect and nothing happens. All BL lights originally lit up before I changed them. All BL lights light up now.

And to diah, yes all strips are exactly the same l and r. When I put the strips in, I have to flip the strips upside down.

I don't know how to test them. Do I just unplug them and test each of those 5 copper pads for voltage.

[Diah]

Re: Sony xbr-75x900f 6 red blink

to clear my understanding..... with flip them 11 & 12 up down they light up all correct ?

[Diah]

Re: Sony xbr-75x900f 6 red blink

about 11 & 12 the cable could be flipped some where we cant see... so the pin on top of LED boards NO 1 will be last at strips. this only explain if all strips are same L & R

but
one things possible... you need to inspect all the ribbon cable contact pins of the strips... you plugged them but the pins are down side so you cant see them if they are in good shape,,, thought the heat of the LED make them dry fast and easily get out from it place or broken.. so give time to inspect them carefully

[EazyBone]

Re: Sony xbr-75x900f 6 red blink

to clear my understanding..... with flip them 11 & 12 up down they light up all correct ?

Nothing lights up ever. Per the service manual 6 blink says backlight but the error thing underneath it says it's the power board LCD screen or main board. And more likely the power board... so am I looking in wrong spot. I can't get the second power board to supply 70v to the LED driver board.

[Diah]

Re: Sony xbr-75x900f 6 red blink

I don't know how to test them. Do I just unplug them and test each of those 5 copper pads for voltage.

no needs volts... read my last post.... and this pads just compare them with chassis as resistance

[EazyBone]

Re: Sony xbr-75x900f 6 red blink

no needs volts... read my last post.... and this pads just compare them with chassis as resistance

Ahh okay, I will test all of them.

Did you see the error diagnosis thing? Says panel, or power board first. Second is main board third being back light possibly.

When no main or panel is even connected it still does the same thing. I'm going to test the chassis and resistance to all as you said but gonna look into this power board

[Diah]

Re: Sony xbr-75x900f 6 red blink

Ahh okay, I will test all of them.

Did you see the error diagnosis thing? Says panel, or power board first. Second is main board third being back light possibly.

When no main or panel is even connected it still does the same thing. I'm going to test the chassis and resistance to all as you said but gonna look into this power board

Man... yours statement... all old BL was light on.. you replace them all and since no BL you have..... so how it come other parts get defect... yes i could be if you wasn't wearing earthing arm band when you working on the TV... but this caused in rate 0.1 %.. so check yours Strips ribbon cable the contact pins first....
trouble shooting should be dome from the bottom then to the top / boards of the TV

[EazyBone]

Re: Sony xbr-75x900f 6 red blink

All old backlights lit up with tester yes. But this was the original problem. I'm already down to the lights so I'm gonna do every check you say first lol. I'm with you here, I just noticed since I am reading manual that it says power board is all. But I will check resistance on everything.

Thx for spending time to respond diah, will get rest of data in a bit!

[EazyBone]

Re: Sony xbr-75x900f 6 red blink

All read OL with chassis and positive to each pad. This is what you mean correct

[Diah]

Re: Sony xbr-75x900f 6 red blink

All read OL with chassis and positive to each pad. This is what you mean correct

on which Ohm level you did testing?

[Diah]

Re: Sony xbr-75x900f 6 red blink

in case only if you did check all Strips ribbon cable contact pins are fine,,, we will move to power boards...
you need to test the PWB as stand alone... so it go
yours standby V. as i can read from photo are low 3.3 V some things.. so we do the following
1- jumper STB to Power on ( this should the SMPS on Hot area go high... and Voltage to the MB exists

2- jumper No 1 always should in place ... we make other jumper STB to T-CON _ON... the pins of T-CON 12V should exist
and STB via 1K Ohm to BL DIM.... here should BL come on... if not check V on LED power broads if it go high and provide V to LED driver-
3- both 1- & 2 should in place we do jumpers STB ..... to BL _ON.......

forget to add the socket between Power boards and Main boards should disconnected

[EazyBone]

Re: Sony xbr-75x900f 6 red blink

Power board mystery solved

Circled in red blew up. Wish I had known that 6 blinks means backlight failure but is most likely power board before lol. Well now we know

[Diah]

Re: Sony xbr-75x900f 6 red blink

hahahaha.... all this 6 pages and you never take the PWB out ....lol

[EazyBone]

Re: Sony xbr-75x900f 6 red blink

hahahaha.... all this 6 pages and you never take the PWB out ....lol

Yea lol . Sometimes you go backwards when you move forwards. Appreciate all the help, slightly expensive mistake but in the end it will only be $120 to fix TV and it was free lol. I learn from my mistakes it won't happen again

[Diah]

Re: Sony xbr-75x900f 6 red blink

Yea lol . Sometimes you go backwards when you move forwards. Appreciate all the help, slightly expensive mistake but in the end it will only be $120 to fix TV and it was free lol. I learn from my mistakes it won't happen again

compare yours last photo of plowing with first post you added photo... seem different to me

[Storyteller12]

Re: Sony xbr-75x900f 6 red blink

If you did the test I mentioned and nothing happened then the blue board (led driver board) is bad

[EazyBone]

Re: Sony xbr-75x900f 6 red blink

I'll eat crow. Yea the LED PSU is blown up. I'll find out in a few days.

[nomoresonys]

Re: Sony xbr-75x900f 6 red blink

Yep, this is why I get that powerboard out and look it over right away, I always check the solder joints too, just in case it's something simple like this. https://www.youtube.com/watch?v=AynXoLjYrKc

[nomoresonys]

Re: Sony xbr-75x900f 6 red blink

Lol, we all dropped the ball on this one, from first post the powerboard is suspect and nobody said well yank it out and look it over front and back.