Philips 47PFS7509/12 LCD TV problem

[janos6662000]

Hi

I have here a Philips 47PFS7509/12 LCD TV which came to me with a weird problem : without signal i could access menu, make a factory reset, access menus, etc.
When i applied cable signal to check image, i had normal picture, but TV was restarting.
I downloaded original firmware and applied the update, but the problem remained.
From a colleague i received a "factory package software" which is a lot bigger.
I made another firmware update, but still did not solve the problem.
Somewhere on the way the error got worse, because at the moment the TV does not boot to menu, i get the Philips logo and stays there forever.
It is not dead, because i can rewrite the firmware as many times i want, but...
I noticed one thing. When i power up the TV with the firmware update stick, i get the "Software update in progress" message.
This goes for only 30 seconds, then TV restarts. Second time the process is much longer, but i think the time differs, i noticed that after 4-7 minutes the TV restarts again, this time to logo, no more "Software update in progress" message.
I left it even 30 minutes, nothing happens.
If i power it down and power it up, i can redo the process, but same happens.
If i remove the USB stick, i get only the logo.
I think that it is an emmc issue, but any idea is welcome.
Maybe i could make an RS232 connection to check the boot messages?
Please share your ideas.

Thanks in advance.
Best regards,
Janos

[nomoresonys]

what kind of signal are you trying, tuner, hdmi, if hdmi did you try another cable?

[janos6662000]

Hello
I was trying cable TV (european standard, RF to tuner), but now i cannot get anywhere, with or without a signal.
What is also interesting, the TV has a Demo picture. When i selected that, got a nice picture, without restarting the TV.
Now... only the logo, or the firmware update message.

[nomoresonys]

Probably not it but won't hurt to try a simple reset. Unplug tv wait 10 minutes-hold power button on tv for 42 seconds-let go-plug tv back in and try it.

[lotas]

Connect via UART and watch the boot log, most likely the eMMC will die.

[nomoresonys]

What's going on with the indicator light on the front of tv, blinking, solid, not on?

[Davi.p]

in recent philips the backlight can make the set to be in total protection, the difference between signal-no signal can be of dynamic B.L. that draws more current on a certain video, post eventually a list of signals on the power board connector, searchng for BL fault signal, this is the most possible for me that answers to fast degradation..

[William1967]

The TPM14.X series are known for the bad caps in the power supply, several caps will be bulged.
Another common problem is the software which makes the TV respond very slowly.

[Davi.p]

you can also try a slight warming of the bga area on the main board or power board, and also watch its solderings or hit it with the handle of screwdriver

[janos6662000]

Probably not it but won't hurt to try a simple reset. Unplug tv wait 10 minutes-hold power button on tv for 42 seconds-let go-plug tv back in and try it.

Hello
I tried the reset, does not help.

Connect via UART and watch the boot log, most likely the eMMC will die.

I will probably try that. I need to build a cable. My UART connector seems to be on jack, being a 7500 series TV

What's going on with the indicator light on the front of tv, blinking, solid, not on?

While it is doing the firmware update, the led is blinking, sometimes slower, sometimes faster. When it has only the logo, the led is off.

in recent philips the backlight can make the set to be in total protection, the difference between signal-no signal can be of dynamic B.L. that draws more current on a certain video, post eventually a list of signals on the power board connector, searchng for BL fault signal, this is the most possible for me that answers to fast degradation..

You mean the Ambilight? I already disconnected that

[janos6662000]

The TPM14.X series are known for the bad caps in the power supply, several caps will be bulged.
Another common problem is the software which makes the TV respond very slowly.

I know it is not OK to judge the capacitors only by looks, but these seem perfectly OK. If you think there is a reasonable doubt, i can desolder the and measure/change them. I attach a picture.

[Davi.p]

i say backlight not ambilight, in the picture i do not see the bottom 4 pins label of connector, can you list them?

But first of all follow what William says , try to apply 12v from external PSU to the tv PSB 12v output, check if the ext psu goes in protection, there are some rare cases of el. caps. that goes short on a certain load, locating the bad dude is a bit complicated , so replacing them all can be an option.. instead of protected psu you can use bench psu with fixed current.. you can also contemporarily add a strong load like 12v 50w light bulb/s to increase curent in el. caps , or you can heat them..

[lotas]

What does the backlight have to do with it if the problem is with the motherboard?

[janos6662000]

OK, this UART idea was brilliant, thank you.
I made a cable, connected to PC with Putty and made a log.
I already see some issues, but i am pretty sure that many if you will see the problem.

eMMC Name: UNKNOWN
Dev Num: 0, Timing Position: 1, Sample Edge: 0x00
Dev Num: 0, Timing Position: 2, Sample Edge: 0x00
: 0
*** Warning - bad CRC, using default environment

It may indicate a bad eMMC, but verifying the firmware update seemed OK.
Please analyze the log and advise.
I also attach a "normal", cold boot log, here i don't see that warning.

Best regards,
Janos