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Old 12-09-2021, 06:59 AM   #1
unimatrix93
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Default Phillips 55PUS6561/12 Black Screen

Hello everyone,

My Philips 55PUS6561/12 (QM16.3E_LA) doesn't produce any image, just a blank black screen. Backlight working fine.

I started troubleshooting the T-CON panel (LC55DQF / 6870C-0549A) and I found a row of capacitor that produce short with my multimeter (Multimeter in Continuity/Beeps on measuring).

I unplugged everything from the T-CON panel to isolate it from the Panel and Mainboard.

I uploading a picture of the caps that shows short.
https://imgur.com/a/QIVlPe1
Could this be the cause of the issue?

Thank you!
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Old 12-09-2021, 07:51 AM   #2
dick_barton
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Default Re: Phillips 55PUS6561/12 Black Screen

When you say short what was the resistance reading across the capacitors?

Always best to add the pictures to your posting using "Go Advanced"

You could also of added to your existing thread since that gives fuller details of what you have done so far.
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Willing to help but I'm no expert.

Last edited by dick_barton; 12-09-2021 at 08:07 AM..
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Old 12-09-2021, 07:55 AM   #3
lotas
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Default Re: Phillips 55PUS6561/12 Black Screen

Vcore is the output voltage supplying the cpu core and it may have a very low resistance relative to gnd, what is the voltage at this point, most likely there should be 1.0v
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Old 12-09-2021, 09:23 AM   #4
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Default Re: Phillips 55PUS6561/12 Black Screen

In the other thread you wrote:
Quote:
Originally Posted by unimatrix93 View Post
Backlight, display working with no data on it, no menu, nothing just blank screen with flashing red power led.
How many times does the LED flash before it pauses for 1.5s and then repeats the sequence?

The service manual that covers your model is available to download from this page, if you don't already have it.
Look at table 2-1 to find out which sections are unique to your specific model.

Chapter 5 is the most interesting part, it covers fault finding.
The blinking error code you are getting is a "layer 1" code, which you can look up in section 5.5.
It's not particularly helpful as you can see in the table in Figure 5-8.
It does say in section 5.5.3 that the more specific "layer 2" codes become visible when the CSM mode has been activated.
However, doesn't the CSM mode require a booting system where your system appears to not boot, I don't understand how that's supposed to work.
It's explained in section 5.1.4 how to activate CSM, you can try that and see if the blinking LED pattern changes, even if you have no feedback on the display.


Quote:
Originally Posted by unimatrix93 View Post
I started troubleshooting the T-CON panel (LC55DQF / 6870C-0549A) and I found a row of capacitor that produce short with my multimeter (Multimeter in Continuity/Beeps on measuring).
Does the multimeter beep continuously when you hold the probes across one of those capacitors, or does it only give one short beep before going silent?
And as has been stated above, do the measurement in resistance mode as that is more useful.
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Old 12-09-2021, 10:44 AM   #5
Diah
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Default Re: Phillips 55PUS6561/12 Black Screen

yours TV Android from 2016.. downgrade the firmware to one from 2018 under name upgrade_loader , after you got the screen back upgrade it to the last version.
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Old 12-10-2021, 04:15 AM   #6
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Default Re: Phillips 55PUS6561/12 Black Screen

Quote:
Originally Posted by dick_barton View Post
When you say short what was the resistance reading across the capacitors?

Always best to add the pictures to your posting using "Go Advanced"

You could also of added to your existing thread since that gives fuller details of what you have done so far.
Sure I will pay attention to it next time!

The reistance on the caps are between 24 and 26 Ohms.

Quote:
Originally Posted by lotas View Post
Vcore is the output voltage supplying the cpu core and it may have a very low resistance relative to gnd, what is the voltage at this point, most likely there should be 1.0v
I measure 1V on Vcore when the TV is on.

Quote:
Originally Posted by Maalobs View Post
In the other thread you wrote:

How many times does the LED flash before it pauses for 1.5s and then repeats the sequence?

The service manual that covers your model is available to download from this page, if you don't already have it.
Look at table 2-1 to find out which sections are unique to your specific model.

Chapter 5 is the most interesting part, it covers fault finding.
The blinking error code you are getting is a "layer 1" code, which you can look up in section 5.5.
It's not particularly helpful as you can see in the table in Figure 5-8.
It does say in section 5.5.3 that the more specific "layer 2" codes become visible when the CSM mode has been activated.
However, doesn't the CSM mode require a booting system where your system appears to not boot, I don't understand how that's supposed to work.
It's explained in section 5.1.4 how to activate CSM, you can try that and see if the blinking LED pattern changes, even if you have no feedback on the display.



Does the multimeter beep continuously when you hold the probes across one of those capacitors, or does it only give one short beep before going silent?
And as has been stated above, do the measurement in resistance mode as that is more useful.
I turned ON the TV and the flashes around 60 times then it stops completely no power led after.

And thank you for your advice about the manual, I will investigate it as soon as I can. It's a continuos beep of course and I also meaasured the caps in resistance mode too.


Quote:
Originally Posted by Diah View Post
yours TV Android from 2016.. downgrade the firmware to one from 2018 under name upgrade_loader , after you got the screen back upgrade it to the last version.
Oh thank you for the file, I will try it out soon and report back!

Thank you everyone I hope we can sort it out!
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Old 12-13-2021, 05:13 AM   #7
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Default Re: Phillips 55PUS6561/12 Black Screen

Quote:
Originally Posted by Diah View Post
yours TV Android from 2016.. downgrade the firmware to one from 2018 under name upgrade_loader , after you got the screen back upgrade it to the last version.
So I tried to downgrade the firmware but I had no luck.

I copied the upg file from the archive to a FAT32 formatted usb stick.
Plugged it in the TV USB2 port, connected to power and I turned on the TV. Then I waited a good 10-15 minutes or so and I restarted the TV without the stick.

No change, still black screen.

What I found is that when I connected the stick back to my computer.
The TV created a "Android" and "LOST.DIR" folder.

The "LOST.DIR" folder is empty.

The "Android" folder has a data folder with 2 com.google... folder and a .nomedia file.
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Old 12-13-2021, 05:30 AM   #8
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Default Re: Phillips 55PUS6561/12 Black Screen

Quote:
Originally Posted by Maalobs View Post
In the other thread you wrote:

How many times does the LED flash before it pauses for 1.5s and then repeats the sequence?

The service manual that covers your model is available to download from this page, if you don't already have it.
Look at table 2-1 to find out which sections are unique to your specific model.

Chapter 5 is the most interesting part, it covers fault finding.
The blinking error code you are getting is a "layer 1" code, which you can look up in section 5.5.
It's not particularly helpful as you can see in the table in Figure 5-8.
It does say in section 5.5.3 that the more specific "layer 2" codes become visible when the CSM mode has been activated.
However, doesn't the CSM mode require a booting system where your system appears to not boot, I don't understand how that's supposed to work.
It's explained in section 5.1.4 how to activate CSM, you can try that and see if the blinking LED pattern changes, even if you have no feedback on the display.



Does the multimeter beep continuously when you hold the probes across one of those capacitors, or does it only give one short beep before going silent?
And as has been stated above, do the measurement in resistance mode as that is more useful.

So I tried to enter CSM mode after reading the service manual.

The display did not show anything, but I found out is that the backlight reacted (changed brightness) after entering the key sequence 123654.

So it's look like the software is there, it's just the display wont draw it?
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Old 12-13-2021, 10:31 AM   #9
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Default Re: Phillips 55PUS6561/12 Black Screen

Quote:
Originally Posted by unimatrix93 View Post
So I tried to downgrade the firmware but I had no luck.

I copied the upg file from the archive to a FAT32 formatted usb stick.
Plugged it in the TV USB2 port, connected to power and I turned on the TV. Then I waited a good 10-15 minutes or so and I restarted the TV without the stick.

No change, still black screen.

What I found is that when I connected the stick back to my computer.
The TV created a "Android" and "LOST.DIR" folder.

The "LOST.DIR" folder is empty.

The "Android" folder has a data folder with 2 com.google... folder and a .nomedia file.
yours TV are working and boot correct also if you now feed it with HDMI signal you will hear the sound ... its known fault of kltich at firmware this why need to downgrade..

1- the USB stick should be MBR mode... read over here how to make USB as MBR mode, i wrote several time on this forum. also dont use over 8Gb USB

2- the firmware should be upgrade_loader.upg

3- while the tv working ( screen black ) at your case plug it out from wall socket... wait 1 minute ... inseret the usb at USB V.2 and press on the RC the power keep pressing then plug it on in wall.... you can try the OK buttom too on the RC. if the yours USB had led indicatore you will see it will blinking .. mean it write the firmware.
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Old 12-13-2021, 11:42 AM   #10
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Default Re: Phillips 55PUS6561/12 Black Screen

Okay then!

I will try again tomorrow, thanks for the detailed guide!
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Old 12-14-2021, 08:49 AM   #11
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Default Re: Phillips 55PUS6561/12 Black Screen

Quote:
Originally Posted by Diah View Post
yours TV are working and boot correct also if you now feed it with HDMI signal you will hear the sound ... its known fault of kltich at firmware this why need to downgrade..

1- the USB stick should be MBR mode... read over here how to make USB as MBR mode, i wrote several time on this forum. also dont use over 8Gb USB

2- the firmware should be upgrade_loader.upg

3- while the tv working ( screen black ) at your case plug it out from wall socket... wait 1 minute ... inseret the usb at USB V.2 and press on the RC the power keep pressing then plug it on in wall.... you can try the OK buttom too on the RC. if the yours USB had led indicatore you will see it will blinking .. mean it write the firmware.
So I tried your tip and I think the system did update but the screen is still black unfortunately.

However, I noticed that there was a bleep sound when the TV started up by itself and I found this log file on the USB too.

recovery.txt
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Old 12-14-2021, 10:38 AM   #12
Diah
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Default Re: Phillips 55PUS6561/12 Black Screen

Quote:
Originally Posted by unimatrix93 View Post
So I tried your tip and I think the system did update... and I found this log file on the USB too.

Attachment 250882
download from Philips this firmware and do it same way again
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Old 12-14-2021, 03:14 PM   #13
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Default Re: Phillips 55PUS6561/12 Black Screen

by the way... the first firmware i wrote to you was service firmware.. mean its auto run firmware.. also when you flash it , i think you kept the usb in place... and this is wrong.. as soon the the TV reboot with it self the usb should take it out and wait for enough time to let the firmware install it self in side the designed block.

however i found for you at 4pda collection of service firmware starting from android 5 to 8
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Old 12-15-2021, 02:40 AM   #14
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Default Re: Phillips 55PUS6561/12 Black Screen

Quote:
Originally Posted by Diah View Post
by the way... the first firmware i wrote to you was service firmware.. mean its auto run firmware.. also when you flash it , i think you kept the usb in place... and this is wrong.. as soon the the TV reboot with it self the usb should take it out and wait for enough time to let the firmware install it self in side the designed block.

however i found for you at 4pda collection of service firmware starting from android 5 to 8
Allright thanks for reminding me!

I will try to install the latest firmware you sent me, then If it's wont help I will try again with the service one and remove the USB stick once the TV is rebooting.

Will report back with the results, thank you!
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Old 12-18-2021, 04:14 AM   #15
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Default Re: Phillips 55PUS6561/12 Black Screen

I couldn't continue working on the TV on the last 2 days because of the Christmas rush in my workplace.

I'm off to some winter vacation with my wife till January, so I will continue this journey then.

I hope we can finish this in january and thank you everyone for helping me with this!

Happy Holidays for you guys until then and take care!
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Old 01-31-2022, 05:28 AM   #16
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Default Re: Phillips 55PUS6561/12 Black Screen

Hey people, I'm back and I have some progress with the TV!

So after checking all the connections I found out that the right t-con flex cable was damaged. Few of the pins were bent, so I took some glue and a tweezer and I tried to put them back into their places. This is how it went, I tested the pins with my multimeter and they show continuity and no short between the lines as far as I see.

IMG_20220128_110201.jpg
IMG_20220128_131823.jpg
IMG_20220128_131821.jpg

Now since this the display do turn on but with pink-blue bars across the screen.
IMG_20220128_135344.jpg

I looked it up and in a SONY service manual, it indicates T-CON failure.

What do you guys think?

Should I replace the flex cable first or should I try to repair/change the T-Con board?

Thanks in advance!
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Old 01-31-2022, 05:47 AM   #17
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Default Re: Phillips 55PUS6561/12 Black Screen

I'd replace that chewed up cable first.
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Old 01-31-2022, 05:51 AM   #18
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Default Re: Phillips 55PUS6561/12 Black Screen

You will not find out the cause of the defect until you replace the defective ribbon.
Change the ribbon.
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Old 01-31-2022, 12:18 PM   #19
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Default Re: Phillips 55PUS6561/12 Black Screen

Sure, that bad cable is probably the reason for the tcon error.
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Old 02-01-2022, 02:44 AM   #20
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Default Re: Phillips 55PUS6561/12 Black Screen

Thank you for the replies, I'm looking for a new ribbon cable right now. Will report back once I changed it!
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