Philips TV keeps restarting, is this MB the same as mine please?

[nomoresonys]

Re: Philips TV keeps restarting, is this MB the same as mine please?

easy thinks first, I usually start with top of board, checking all diodes and resistors and checking all solder joints on bottom of board, those for starters, examples of bad solder joints there: https://www.google.com/search?q=bad+...ih=607&dpr=1.5

[alfonzzo]

Re: Philips TV keeps restarting, is this MB the same as mine please?

Thanks nomoresonys I'll make sure to check all of this.

I made the measurements again, 2 ways:

1) with the positive probe on LED1+ :
Depending on what's on the screen (nothing, logo, or plain light) all the 4 LED1- points go from 0v then 32v then 35v then 37v then stabilize at 39V

2) with the negative probe on the chassis
The 4 LED1- points go from 0v then 8v 10v 15v and stabilize at 6.5v

All these values cycle while the tv starts over and over again

[nomoresonys]

Re: Philips TV keeps restarting, is this MB the same as mine please?

doesn't look right at all, try this, unplug backlight cable, and recheck the pins on connector on the board.

[alfonzzo]

Re: Philips TV keeps restarting, is this MB the same as mine please?

Ok I unplugged the connector, here are the values:

1) with the positive probe on LED1+ :
0v on all the 4 LED1- points

2) with the negative probe on the chassis
0.9v on all the 4 LED1- points

[nomoresonys]

Re: Philips TV keeps restarting, is this MB the same as mine please?

try this, plug everything back in power it up, check voltages on CN9101, what are they and do they fluctuate?

[alfonzzo]

Re: Philips TV keeps restarting, is this MB the same as mine please?

try this, plug everything back in power it up, check voltages on CN9101, what are they and do they fluctuate?

here are the measurements please check the pic below, they don't fluctuate thank you (negative probe was on the chassis)

[Diah]

Re: Philips TV keeps restarting, is this MB the same as mine please?

show us the print chart of this socket CN9101

[Maalobs]

Re: Philips TV keeps restarting, is this MB the same as mine please?

The service manual that covers your model can be downloaded from this page.
The service manual is for a chassis that is shared among several models, so refer to Table 2-1 to find the diagrams and schematics that are specific to your particular model.
Other than that, focus on chapter 5.

There is no hardware SDM in this model, in section 5.2.2 it says:

In this platform, a simplified SDM is introduced (without protection override [...])

There is also no table that explains the "blinking LED" diagnostics, even though there is a section "5.6 The Blinking LED Procedure".
It might be that either section 5.6 is a copy/paste mistake and should not have been included in this service manual, or that the table was mistakenly omitted.

Regarding the boot-cycling; if you plug in mains power and just let the TV be for several minutes, does it eventually start blinking the power LED?
The boot-cycling might be a symptom of a number of retries in the boot-process, and if you let it run until the maximum allowed retries have been reached, the TV might fall into a protection mode and start blinking the LED.

If you have the ability to read the TX from the Standby controller UART and from the MIPS (main processor) UART, maybe there is information about what is going wrong in the boot-process.

--------------------------------

show us the print chart of this socket CN9101

Were you looking for this?

[Diah]

Re: Philips TV keeps restarting, is this MB the same as mine please?

thanks Maalobs. we do know the start boot script first section to load Logo there are no protection. after logo steps start the protection. from the chart i would like him first to termenated at the scoket CN9101 pins 9&10. as this line not only for audio but i think for Tuner too. if there any fault at MB audio or tuner section.. tv should boot complete.

[alfonzzo]

Re: Philips TV keeps restarting, is this MB the same as mine please?

Thank you much Maalobs, even if I understood half of what you wrote (because of my lack of knowledge) I'm sure it's very clever stuff
Ok I plugged the TV it's 3:48pm let's see for how long it will reboot, I'll check the red led regularly to see if it comes up.
Downloading the service manual right now thank you.

Thanks Diah for the following up. The CN9101 seems to only have 7 visible pins (I measured them in post #46) , how can I measure pins 9&10 please?

[alfonzzo]

Re: Philips TV keeps restarting, is this MB the same as mine please?

<removed>

[Diah]

Re: Philips TV keeps restarting, is this MB the same as mine please?

you have 14 pins. they are 2 line of pins

[alfonzzo]

Re: Philips TV keeps restarting, is this MB the same as mine please?

Ok I removed the connector to be able to see all of the pins.
Here are the measures I got (connector removed).
I won't be able to take measurement with the connector on, because it's not accessible for me due to all the components around, there is no place to put the probes. So I had to remove the connector.


@Maalobs, tv is on for around 1h30 now and still rebooting, no red light.

[Maalobs]

Re: Philips TV keeps restarting, is this MB the same as mine please?

I don't know about clever, but reading the serial output from the processor during the boot-up can give you a lot of information about what's going on, as shown here.

The SDM (Service Default Mode) when it was a hardware feature, and your TV is from that era, was a way to force the TV to keep all power rails on even when the TV enters protection mode.
This would allow you to measure each rail and to find short circuits.
This is what Diah was asking about to find on the main PCB.

If you had it running for 90 minutes and there was no blinking, then keep following Diah's instructions.

[alfonzzo]

Re: Philips TV keeps restarting, is this MB the same as mine please?

How can I boot into this SDM mode so I can get the processor informations?
I guess it's like booting into safe mode on windows laptops.
I still have the original remote, the tv doesnt respond to it though.

Ok let's follow Diah's advice Thanks guys !

[Diah]

Re: Philips TV keeps restarting, is this MB the same as mine please?

LOL Maloobs, what we can more if his knowledge not as expected..
@alfonzzo:
SDM are soldering point will be find on the Main Boards if we shorted to chassis this mode will be active.. but as Maloobs wrote regard to the service manual your boards didn't have, so forget this point.
another point you didn't understand it what Maloobs wrote.. about capture the boot log. this procedure need USB TTL or USB to serial adapter and use any terminal at windows or Linux .. we connect RX and TX of the adapter to UART port which you have on the MB. this will show us the start protocol on the Terminal. i am not sure if you are able to this test point.!!
let see the area of the main CPU on the mainboards.. from downside like this photo you upload i can see there are change at the boards color caused by heating.. if this the case mean the Main CPU could got BGA issue because of the heat.. so remove first the heat sink which cover the main IC, and show us clear photo of the back side exactly the area under the Soc. and you can confirm with your eyes if what i mentioned color change was true or not.

[alfonzzo]

Re: Philips TV keeps restarting, is this MB the same as mine please?

Yep I just have a multimeter guys I can't capture the boot log with a USB to serial adapter.

Ok let's take a look at the CPU then, Diah could you please confirm I just have to unsolder these 2 pins to remove the heat sink and have access to the cpu? thanks

[Diah]

Re: Philips TV keeps restarting, is this MB the same as mine please?

no. dont unsolder them.. from the top at the heat sink they are connected as clip.. look carfully

so what i mentioned bnefore was correct the area of the CPU realy warm and changed color...
your BL even if they are defect... yours tv will work because we dont have BL_Error pins on the socket CN9101. so the issue on MB
try to unplug any load on the MB like wifi speaker.. and turn on.. also you can disconnect the IR section too.. if thius didnt help i assume you have 99.9% BGA on the main IC

[alfonzzo]

Re: Philips TV keeps restarting, is this MB the same as mine please?

Thanks, here is a video I can't see any clip
https://streamable.com/ieuw8y

There is no other equipment linked to the tv, no wifi speaker nothing.
Thanks

[Diah]

Re: Philips TV keeps restarting, is this MB the same as mine please?

leave it.. you need other MB... if you have hot air Gun good to try heating this heatsink from top with 280° 3 minute .. so it could help if there BGA on Soc will be connect again