Philips 42PFL7108K/12 dead

[Nawual]

I have this tv that is completely dead. Not even the power led.
The PSU is this model FSP140-4FS01.
I have measured the voltages and I have no voltage, not even on the standbye pin which is 10.
I have removed it from the TV and plugged it in alone and there is still no voltage on that pin but I have almost 300 in the primary capacitor.
My question is if this model of PSU when tested outside the TV, does not have the voltage on pin 10 of STB, or is it faulty?

[IMG][/IMG]

[IMG][/IMG]

[IMG][/IMG]

[trunks81]

Re: Philips 42PFL7108K/12 dead

You should have 3V3 on that pin even tested outside of the TV,
Which voltage to you have on the + and - of the recitifier ?

[budm]

Re: Philips 42PFL7108K/12 dead

I have this tv that is completely dead. Not even the power led.
The PSU is this model FSP140-4FS01.
I have measured the voltages and I have no voltage, not even on the standbye pin which is 10.
I have removed it from the TV and plugged it in alone and there is still no voltage on that pin but I have almost 300 in the primary capacitor.
My question is if this model of PSU when tested outside the TV, does not have the voltage on pin 10 of STB, or is it faulty?

[IMG][/IMG]

[IMG][/IMG]

[IMG][/IMG]

Just to be clear, you do not have ANY Voltages on any pin of the connector on the cold side?
STB pin is not Standby power supply output pin, it is PS-ON pin for getting the on control signal from the main board.
Looking at the picture #3, it looks like this TV use 12V Standby Voltage, I see 12VSSB pin labels, and 3V3S for 3.3V standby. I can tell more when I see better pictures.
Please attach good clear pictures of the board using 'Go Advanced'. Right now I cannot read any prints on the board due to pictures are not in focused.
BTW, what is the chassis number as printed on the model number sticker on the back of the TV?

[thommyX]

Re: Philips 42PFL7108K/12 dead

The power supply does not normally break. 99% of the time it is the mainboard. Your device should make a blink code after about 2 to 3 minutes !!!

http://monitor.espec.ws/section31/topic313630.html

LG Thomas

[Nawual]

Re: Philips 42PFL7108K/12 dead

Hello again.
Well, something strange happened, I started to measure the voltages in the rectifier capacitors and I have 300v.
The strange thing is that I measure pin 10 STB again and now I do have 3v3.
All this with the PSU outside the TV.
Now I'm not sure which pin to jumper for the PSU to give me the rest of the voltages

[Nawual]

Re: Philips 42PFL7108K/12 dead

Hello, I upload a better photo of the pins and the chassis number.
What I do not know which I have to join to have all the voltages and turn on the LEDs and thus check that the PSU is fine

[IMG][/IMG]

[budm]

Re: Philips 42PFL7108K/12 dead

..

[budm]

Re: Philips 42PFL7108K/12 dead

Hello again.
Well, something strange happened, I started to measure the voltages in the rectifier capacitors and I have 300v.
The strange thing is that I measure pin 10 STB again and now I do have 3v3.
All this with the PSU outside the TV.
Now I'm not sure which pin to jumper for the PSU to give me the rest of the voltages

1) Are you testing the Voltages with all the connectors in place.
2) "10 STB again and now I do have 3v3" Are you saying you now have 3.3VDC on STB pin 10? What do you have on pin 9 3V3S pin, 3.3Vdc?
3) What are the Voltages on the other pins? We need those readings!
4) Does the Voltage on the STB (PS-ON) change state when you turn the TV on and off? what is the STB Voltage when TV is OFF and when the Power switch is turned on? I need this information to find out if STB (PS-ON) is Active HI, or Active LO control signal..

[trunks81]

Re: Philips 42PFL7108K/12 dead

Can you check the next ? remove the heatsink from the BGA and if it is an Fusion IC
If it is you need to reball this one

[Nawual]

Re: Philips 42PFL7108K/12 dead

Hi all. I managed to repair this tv. I want to thank everyone for your ideas and help and I will explain how I have found the fault in case it can help someone in the future.
When turning on the TV, the standby LED does nothing but I have all the tensions in the PSU, which are these:
Pin:
-9: 3.4v
-11 and 12: 12vssb 12v
-10: 3v3
-13 and 14: VSN 12v
-17 and 18: BLON AND BLIC 0V
-19: Din1 0v
-21 and 22: Val bo 12v
-25 and 26: 12vssb 12v

After about three minutes, the standby LED turns on twice and goes off, and so on continuously. At that time I no longer have the tensions. Only pins 9 and 10 of 3v3 remain.
I turn the tv off and on again and I have all the tensions again. Then I measure the voltages on the mainboard and notice that they are all and there is no short.
So I decide to reflow the main chip. After it cools down I turn on the tv and it works perfectly.
I don't know why in the first measurements I didn't have any tension, surely I didn't measure well.
Anyway, thank you all.

[Deusjevoo]

Re: Philips 42PFL7108K/12 dead

Reflow probably won't last.
Got some of those reflowed fusions since beginning 2019, all failed again within 3 months usually.
First ones I reballed are still running for +/- 1.5y now.

If it fails again and you want to keep it running, (let it) reball.
Some pads are probably oxidated, turned black, whatever not making full contact anymore.
Heath = oxidation. Reflowing it everytime it fails can make the pad contact areas smaller every time (oxidation grows) untill it fails.
Too much uncontrolled heath cycles can also destroy the glues holding the layers etc. resulting in ripping pads when lifting it. (Guess who'll be blamed...)