Samsung QN75Q60TAF Boot Loop fixed but no picture

[Diah]

I was able to isolate the issue down to pin 7 specifically, and I was able to trace it down to a 56-ohms resistor at the end of the buffer board. You can see the resistor in the picture attached marked with red, and pin 7 is connected to the side pointed by the arrow. I checked ohms across the resistor and it reads good.

I tried to find where the other side of the resistor led, but I wasn't successful. Also, I did as suggested and disconnected the U ribbon cable, and the lines disappeared that time.

I am not sure if I should try to re-flow/replace that resistor, or go down another route. Thanks for the suggestions.

the other end of the R going to the gate Transistor in display which it seem shorted as know issue with this model.
but i would suggest trying to remove yours mask on the U ribbon cable.. and just release one legs of this R then see if the screen come clean.

[Hendrink]

did you trace the pins 7,8 where they go... to the end of buffer boards.. there may ESD diode shorted

also with out this U ribbon cable you will have 3/4 screen... did the line remain showing or disappear

I was able to isolate the issue down to pin 7 specifically, and I was able to trace it down to a 56-ohms resistor at the end of the buffer board. You can see the resistor in the picture attached marked with red, and pin 7 is connected to the side pointed by the arrow. I checked ohms across the resistor and it reads good.

I tried to find where the other side of the resistor led, but I wasn't successful. Also, I did as suggested and disconnected the U ribbon cable, and the lines disappeared that time.

I am not sure if I should try to re-flow/replace that resistor, or go down another route. Thanks for the suggestions.

[Diah]

I was able to fix the Boot Loop by masking pins 7-8 on the flex cable that connects to the right
Any information that helps me solve this problem would be greatly appreciated.

did you trace the pins 7,8 where they go... to the end of buffer boards.. there may ESD diode shorted

also with out this U ribbon cable you will have 3/4 screen... did the line remain showing or disappear

[Hendrink]

I also have the Boot Loop issue with this exact same TV, the QN75Q60TAF. After reading through this forum and the "SAMSUNG UN50TU8000F rebooting, backlight ok. No 12v to panel boards" forum, I got the TV to turn on with image and everything, but a bunch a reddish horizontal lines display on the screen. The lines are not too noticeable, but they still affect the quality of the image.

I was able to fix the Boot Loop by masking pins 7-8 on the flex cable that connects to the right side buffer board, but I can't get rid of those reddish horizontal lines on the display. I have tried checking all the caps with a multimeter, I have tried injecting voltage into the board to find a short, and I have tried to follow the rails to find the issue. Unfortunately, I haven't been successful.

I would also like to mention that I don't have a lot of experience troubleshooting electronics, but I have a solid foundation in electrical systems. I have also tried to find the schematic for this TV, but I have been unsuccessful.

Any information that helps me solve this problem would be greatly appreciated.

[Nicktronic]

Wiring diagram...

[Nicktronic]

Re: Samsung QN75Q60TAF Boot Loop fixed but no picture

Wiring Diagram

Hey again, I have another Q60TAF (70" this time) and I've confirmed that if I isolate the any ONE of the following pins, the TV will stop boot looping (but still doesn't show a picture). I've found no shorted caps on the buffer boards. Pins 1, 11, 22, 28 and 82. Based on the wiring diagram of CN1300, which of these pins is critical to allowing a picture to show on screen?

[nomoresonys]

Re: Samsung QN75Q60TAF Boot Loop fixed but no picture

Well it was not a success BUT it's a damn interesting thread with some good info in it.

[Nicktronic]

Re: Samsung QN75Q60TAF Boot Loop fixed but no picture

Installed both the new SPI flash and the diode packs. Same result. I'm done with this TV, it's going to the recycling depot.

[Nicktronic]

Re: Samsung QN75Q60TAF Boot Loop fixed but no picture

Now you need to solder a clean spi flash and check with it.

Once I receive it, I will. I ordered new diode packs as well.

[lotas]

Re: Samsung QN75Q60TAF Boot Loop fixed but no picture

Now you need to solder a clean spi flash and check with it.

[Nicktronic]

Re: Samsung QN75Q60TAF Boot Loop fixed but no picture

Remove DT601 and DT602 and all of them are not needed, they cause more problems.
After removal, check to turn on the TV without spi and 601, 602.

No difference, boots up, samsung jingle, backlights on, no picture

[Diah]

Re: Samsung QN75Q60TAF Boot Loop fixed but no picture

Haha, maybe!

do it as lotas suggest to remove both DT.... maybe this is the wounder you are waiting for... you will not lost anythings.

[Nicktronic]

Re: Samsung QN75Q60TAF Boot Loop fixed but no picture

you placed order for new SPI and DT.. change them as they both low coast.
who knows.. maybe there will be wounder !!!

Haha, maybe!

[Diah]

Re: Samsung QN75Q60TAF Boot Loop fixed but no picture

@diah, it's ok, and I thank you for all the help, do you think the panel is causing the problem and therefore the TV is garbage/recycle?

you placed order for new SPI and DT.. change them as they both low coast.
who knows.. maybe there will be wounder !!!

[Nicktronic]

Re: Samsung QN75Q60TAF Boot Loop fixed but no picture

his problem not about boot loop as before... tv will turn on even if he remove both DT.. the questions there will be no picture... because t-con cut it off before removing the spi or the masking he did.
i wish i am wrong for his sake.

@diah, it's ok, and I thank you for all the help, do you think the panel is causing the problem and therefore the TV is garbage/recycle?

[Nicktronic]

Re: Samsung QN75Q60TAF Boot Loop fixed but no picture

Remove DT601 and DT602 and all of them are not needed, they cause more problems.
After removal, check to turn on the TV without spi and 601, 602.

Ok, I will try that

[Diah]

Re: Samsung QN75Q60TAF Boot Loop fixed but no picture

his problem not about boot loop as before... tv will turn on even if he remove both DT.. the questions there will be no picture... because t-con cut it off before removing the spi or the masking he did.
i wish i am wrong for his sake.

[lotas]

Re: Samsung QN75Q60TAF Boot Loop fixed but no picture

Remove DT601 and DT602 and all of them are not needed, they cause more problems.
After removal, check to turn on the TV without spi and 601, 602.

[Nicktronic]

Re: Samsung QN75Q60TAF Boot Loop fixed but no picture

Not yet known.

I think @diah is saying the T-Con circuit is toasted on the MB, do you disagree? New MB then?

- GD25B32C I/O NOR Flash had leak. not shorted
- DT602 had leak

I'm waiting for a new SPI Flash, should I also order a new DT602?

[lotas]

Re: Samsung QN75Q60TAF Boot Loop fixed but no picture

So your opinion is that the panel has the problem and there's no way to fix?

Not yet known.