Sony xbr-75x900f 6 red blink

[nomoresonys]

Re: Sony xbr-75x900f 6 red blink

Make sure that fuse on your blue board is good, you prolly already checked it.

[EazyBone]

Re: Sony xbr-75x900f 6 red blink

Repeat... check the led psu output in the early seconds after power up...
the STM32 cpu can be programmed with a big free software from ST website and a cheap i2c adapter or a ch341a (don't remember), but it's quite hard and is also hard find firmware.. the power on the blue board must be checked in early seconds!!

So the only voltage that comes out of the PSU LED is 12 V. I plug in the TV and 12 goes to 12 and immediately starts dropping. I then hit power and 12 V goes to 12.74 and stays consistent for like 5-8 seconds and then drops to zero again. No voltage ever hits the fuse of the driver board. Randomly I will get like .050 volts and it'll drop again. But never over .050 so nothing is happening. But the driver board does get 12v. Also pins j752/51/49 etc etc get 33V consistent during the time where 12V is consistent then drops at the same time.

https://youtu.be/piuV_mBrGv8?si=MTD6fjHgTXEd88Hm

If I unplug the LED driver from the main board and tcon cables the 12 V stays consistent to LED driver and red and yellow LEDs on driver board flash repeatedly and never shuts down. Still no voltage to the LED driver besides the 12 V and backlights do not come on. But the TV turned on and has sound! But no backlight. So are we on the right track with backlights still? Lol

[Davi.p]

Re: Sony xbr-75x900f 6 red blink

The led psu (i call it psb.. however..) is a flyback, forward or similar power supply followed by a 12v dc to +vled boost ps, where +vled is probably about 60/70v (see the electrolitics rated 80v on blue board), depends on the BL leds organization to know how probably them are damaged, since storyteller tells leds are 12v and the basic average voltage is more than 12v, then there are many leds in series, but anyway is somehow a local dimming set, so probably some leds are bad.. also 12v leds are not the best thing as reliability.. since is a local dimming i don't see the reason why a group of leds with a short cannot be isolated.. and the led bars how them are? Probably many small bars, must be checked one by one..

[EazyBone]

Re: Sony xbr-75x900f 6 red blink

The led psu (the best is to call it psb.. however..) is a flyback, forward or similar power supply followed by a 12v dc to +vled boost ps, where +vled is probably about 60/70v (see the electrolitics rated 80v on blue board), depends on the BL leds organization to know how probably them are damaged, since storyteller tells leds are 12v and the basic average voltage is more than 12v, then there are many leds in series, but anyway is somehow a local dimming set, so probably some leds are bad.. also 12v leds are not the best thing as reliability

As a note, I've already put a offer in on new set for eBay and was accepted yesterday. Forgot I did that so already a new set on the way. But I should of checked all the boards first. And thanks for being cool everyone.

[EazyBone]

Re: Sony xbr-75x900f 6 red blink

The led psu (i call it psb.. however..) is a flyback, forward or similar power supply followed by a 12v dc to +vled boost ps, where +vled is probably about 60/70v (see the electrolitics rated 80v on blue board), depends on the BL leds organization to know how probably them are damaged, since storyteller tells leds are 12v and the basic average voltage is more than 12v, then there are many leds in series, but anyway is somehow a local dimming set, so probably some leds are bad.. also 12v leds are not the best thing as reliability.. since is a local dimming i don't see the reason why a group of leds with a short cannot be isolated.. and the led bars how them are? Probably many small bars, must be checked one by one..

Well here they are in glory. I checked them all with LED tester, and I can only get 4 to light up at once lol this TV is a beast on power. I have not found a bad LED with the tester. They all light up. I get the LEDs today. Is there something I should do to test them further..? Cause shiiiiit.

Also this is the worst TV I have ever taken apart. It took 2 friggin hours easily and everything is taped down or glued down. Literally everything. It has screws holding the screws in place. It had glue holding the glue down, and tape holding the tape down. Absolutely nasty TV. I had to write a book on how to take it apart so that I can do it in reverse.

Thinking I'm just going to replace them all anyways since I got the code and I have them.. but what is y'all's thoughts. There's like 200 lights and all are 12v ����������

And Sony, very late response I tested that fuse yes. Thanks

[Diah]

Re: Sony xbr-75x900f 6 red blink

i don't know why so long discuss lead over here and allot of idea..
you have DM test one by one with Diode mode.... one direction will lit dim.. and reserve way check if there are ziner reading.... if yes... the tester will not discover open or shorted ziner at LED

[Davi.p]

Re: Sony xbr-75x900f 6 red blink

Ziner ... ma va va va.. berlefus..

my opinion if you were sure of bad leds so an huge replacement was possible, but this way i would personally try to find a replacement blue board..

[EazyBone]

Re: Sony xbr-75x900f 6 red blink

i don't know why so long discuss lead over here and allot of idea..
you have DM test one by one with Diode mode.... one direction will lit dim.. and reserve way check if there are ziner reading.... if yes... the tester will not discover open or shorted ziner at LED

Not sure if I'm doing something wrong but diode mode won't light any of these at all. And when you say ziner, do you mean zener? I am trying to Google ziner and don't find anything. Reverse way zener, as in ohm resistance?

When I use diode mode negative to negative positive to positive nothing lights up and just says OL

And davi, I may need a replacement blue, but I already bought these lights and I'm not gonna open it a second time so they gonna go in.

[Diah]

Re: Sony xbr-75x900f 6 red blink

EazyBone
ziner in german... LOL zener... well if your DM with 9V battery it will, i dont know yours DM... but my the Diode mode and peep ton option are at same setting

[nomoresonys]

Re: Sony xbr-75x900f 6 red blink

i don't know why so long discuss lead over here and allot of idea..
you have DM test one by one with Diode mode.... one direction will lit dim.. and reserve way check if there are ziner reading.... if yes... the tester will not discover open or shorted ziner at LED

Can you clarify, one way lit dim, other way what should he expect to see for a reading, are you saying the tester can not tell if the zener/ziner is bad?

[Diah]

Re: Sony xbr-75x900f 6 red blink

Can you clarify, one way lit dim, other way what should he expect to see for a reading, are you saying the tester can not tell if the zener/ziner is bad?

lit dim not as we understand lighting up... its just the middle of the LED will be very very dim... need good eyes to notice it,,, at reserve way if there are zener it will read 0.75-0.68 in diode mode... any which read below 0.5 are bad .. or shorted... of course only to LED BL with zener. like in LG Panel

LED Tester will lighting the led even if the zener open.. so its good to use only with BL LED with out zener protection build in

[nomoresonys]

Re: Sony xbr-75x900f 6 red blink

Seems like it's hard to tell which tvs have the zeners and which ones don't, unless it's tore down to see the backlights and test or is it in a description when you buy backlights or look them up?

[EazyBone]

Re: Sony xbr-75x900f 6 red blink

lit dim not as we understand lighting up... its just the middle of the LED will be very very dim... need good eyes to notice it,,, at reserve way if there are zener it will read 0.75-0.68 in diode mode... any which read below 0.5 are bad .. or shorted... of course only to LED BL with zener. like in LG Panel

LED Tester will lighting the led even if the zener open.. so its good to use only with BL LED with out zener protection build in

Actually many of them read below .5 several read .258 only a couple were up to .75.

Interesting. Okay well I have replaced all of them anyways as I think it'll just be better since I ordered them anyway. Putting this beast back together. Will share results when done

[nomoresonys]

Re: Sony xbr-75x900f 6 red blink

I hope you tested the new ones before assembly, sometimes they come defective.

[EazyBone]

Re: Sony xbr-75x900f 6 red blink

I hope you tested the new ones before assembly, sometimes they come defective.

I did test them. And lo and behold it didn't work. Still same error

[EazyBone]

Re: Sony xbr-75x900f 6 red blink

Also now all my test voltages are negative... why all negative???

[Davi.p]

Re: Sony xbr-75x900f 6 red blink

voltages tests of what?

[EazyBone]

Re: Sony xbr-75x900f 6 red blink

voltages tests of what?

Literally anything. Pb to main, backlight error which still exists. Second pb voltages every is negative lol

[EazyBone]

Re: Sony xbr-75x900f 6 red blink

So I can't get the error to stop. I tried the method of taking the bl err out of the PB out housing and grounding it so the main board doesn't know, yet still I get the 6 blink code. The only time I can get anything .

So I get stby at 3.5. I turn on TV and 12v goes to LED PSU. 12v goes to tcon and main board. 12v hits LED driver board. It turns on a yellow light, then flashes red a code or something, I put a video.
The LED driver board never gets the I assume 30v (from another thread) on and of the VCC and LED driver fuse never gets any voltage either. I can disconnect anything anywhere and the LED driver PSU never sends the voltage down it's pins. Other places on the LED PSU show 35v on several places but never at the pins. The 6 blink code continues any which way.

If I disconnect the TCON from the main AND the LED driver from main, TV turns on and sound is heard but still never any backlight. Can't even get it to flash.

And I connect red and black backwards that's negative, sometimes just need a break from tvs lol lose your mind

Video shows LED driver blink code if it means anything
https://youtu.be/X0S4a_F7VEc?si=r0qhiWQ7QnTpeXdk

Doesn't anyone know if the 12 v that goes from PSU to ledpsu to LED driver then the driver says, everything is okay please send more.voltsge, then the LED PSU turns on?

[nomoresonys]

Re: Sony xbr-75x900f 6 red blink

Maybe your ld board is bad, those are usually not that much to buy.