Overnight our Philips TV (55PUS6162/12) started behaving badly.
Unfortunately I'm quite the newbie with this stuff, so I am a bit uncertain what to do, but I detailed everything I've observed and done based on various guides I found on the internet. I also read the "Basic troubleshooting guide" from here, but it seems already not basic enough for me, besides confirming my suspicion that the power supply board is at fault.
When plugging the TV in it turns on by itself. But only the backlight will turn on, the screen will stay completely black and no sound will play and the power indicator LED is also not turning on. It's also not possible to turn off the TV via the remote (there's no power button on the TV itself).
When contacting Philips customer support (after giving a couple power cycles a try) they gave us a software upgrade that we should install via a USB stick, but given we don't have any image we don't know if it actually worked. Only thing we know is that it didn't fix the issue we had, but maybe we have new software on the main board now
Given the current situation I would have to ship the TV to a repair shop, which is ridiculously expensive where I live, so I decided to open up the TV instead and give it a try at manually fixing it.
Unfortunately neither the power supply board nor the main board have any visible damage like bulging capacitors or burned components.
I did a couple checks on diodes and transistors in the circuit, some of which behaved weirdly, but I guess measuring in circuit is not really reliable. Before unsoldering anything I wanted to get a second opinion.
I also tried to measure standby voltage, but it's not clearly labeled. But I guess it is the 3.5V label, aka the lowermost pin. Measuring the voltage on that I saw a steady and really quick drop. Plugging in and positioning my multimeter it already was at ~2V and within 5 to 10 seconds it's down to 8mV, which might as well be 0V in the context. The behavior is the same with the Main Board and/or backlight unplugged.
If I would have to improvise here I would desolder random transistors and check if they are good or not, but it feels like there could be a better way here.
To note, I don't have an ESR meter, just a regular multimeter. These ESR meters are also quite expensive and buying one would not really be financially sensible considering the TV is already 3 years old and I don't plan on doing this stuff more often.
Which component could cause that behavior?
What other measurements could I do before unsoldering anything?
Unfortunately I'm quite the newbie with this stuff, so I am a bit uncertain what to do, but I detailed everything I've observed and done based on various guides I found on the internet. I also read the "Basic troubleshooting guide" from here, but it seems already not basic enough for me, besides confirming my suspicion that the power supply board is at fault.
When plugging the TV in it turns on by itself. But only the backlight will turn on, the screen will stay completely black and no sound will play and the power indicator LED is also not turning on. It's also not possible to turn off the TV via the remote (there's no power button on the TV itself).
When contacting Philips customer support (after giving a couple power cycles a try) they gave us a software upgrade that we should install via a USB stick, but given we don't have any image we don't know if it actually worked. Only thing we know is that it didn't fix the issue we had, but maybe we have new software on the main board now
Given the current situation I would have to ship the TV to a repair shop, which is ridiculously expensive where I live, so I decided to open up the TV instead and give it a try at manually fixing it.
Unfortunately neither the power supply board nor the main board have any visible damage like bulging capacitors or burned components.
I did a couple checks on diodes and transistors in the circuit, some of which behaved weirdly, but I guess measuring in circuit is not really reliable. Before unsoldering anything I wanted to get a second opinion.
I also tried to measure standby voltage, but it's not clearly labeled. But I guess it is the 3.5V label, aka the lowermost pin. Measuring the voltage on that I saw a steady and really quick drop. Plugging in and positioning my multimeter it already was at ~2V and within 5 to 10 seconds it's down to 8mV, which might as well be 0V in the context. The behavior is the same with the Main Board and/or backlight unplugged.
If I would have to improvise here I would desolder random transistors and check if they are good or not, but it feels like there could be a better way here.
To note, I don't have an ESR meter, just a regular multimeter. These ESR meters are also quite expensive and buying one would not really be financially sensible considering the TV is already 3 years old and I don't plan on doing this stuff more often.
Which component could cause that behavior?
What other measurements could I do before unsoldering anything?
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