Phillips TV repair - help with identifying bad caps

Thread Starter

MarioBlacksmith

Joined Oct 5, 2018
2
Hello,

my phillips tv 47PFL6007D/30, 5 years old, has been giving me a hard time lately. it does not turn on immediately , and sometimes it just refuses to turn on. the red led that is supposed to go blue when turned on, just disappears for 2 seconds and goes red again. tried power cycling...
I've read that bad capacitors might be the culprit. i opened the case but did not identify bad caps right away. I love fixing things on my own, and i have handled a soldering iron before, but no capacitors :)

i uploaded a few pictures so someone could help me with that:


https://ibb.co/mqXbeK
https://ibb.co/cB96eK the upper bunch, the lower 2 capacitors maybe ?
https://ibb.co/cs1PYe closeups of the above
https://ibb.co/b3i4Ye closeups of the above
https://ibb.co/c1RDRz does this look ok ?

much appreciated!
 

wayneh

Joined Sep 9, 2010
17,167
Bad caps in something only 5 years old is odd but not impossible. Unfortunately you can't usually tell much by looking at them unless there has been an obvious bulging or bursting. I have to admit that some of those pictures hint at bulging. I wouldn't have thought much about it but it appears that some of the nearby ones look very flat on top while a few look slightly domed.

The way to test capacitors is with an ESR meter. I built my own but after all was said and done, I realized it would usually be faster and easier to simply replace every electrolytic. This saves the time you would spend testing, and you get a full set of fresh caps out of the deal. That isn't a total waste, since having fresh caps will likely extend the life of the unit.

Do you have the service manual for this TV? The schematics and test procedures can be very useful.
 

Hymie

Joined Mar 30, 2018
1,080
Electrolytic capacitors are well known to fail and cause the sort of issues you have with your TV.

My advice is to carefully inspect each electrolytic capacitor for any indication of damage, especially bulging of the can due to internal pressure build-up.

Although very much a stab in the dark, I’m going to suggest one of the three circled in the attached photo. Although these are in the primary circuit (if I’m correct) they are associated with the PSU switching IC – failure of one or more can result in the switching circuit failing to start.

One of these capacitors will be providing the dc voltage to the IC before the PSU switching circuit starts, typically it will have a value of 1 – 10uF at 50V (this is the one I’d go for).

However, given that you will have to remove the PCB assembly to replace the capacitor – I’d give serious consideration to replacing all the electrolytic capacitors. Make sure that you observe the correct polarity when replacing them and use capacitors with a 105C rating for maximum life.
 

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drc_567

Joined Dec 29, 2008
1,156
At the outside chance, spray electrical contact cleaner into the manual power on switch and cycle it a few times. Occasionally, humidity, smoke, or other particulates will create a problem of this nature.
 

SLK001

Joined Nov 29, 2011
1,548
Late model PSs aren't likely to fail due to bad caps. You need to measure the voltages on the connector going to the mainboard. The results of these measurements will guide you to the failure.
 

ebp

Joined Feb 8, 2018
2,332
It looks to me like there are three separate switchers on that board. One is probably the main supply (biggest transformer, centre right & all the parts in the upper right), one a stand-by supply (lower right) and one likely active power factor correction (left side). I also think it very likely that the back of that circuit board is crammed with surface mount components.

I suspect that the power factor correction and main supply are enabled when the set is turned on with the remote control. The indicator LED is probably controlled by a microprocessor that may be monitoring several supply voltages. If all is well, turn-on is completed and the blue LED turns on. If something is wrong, it probably returns to standby. It is possible that the standby supply has its load increased significantly when turn-on is attempted and it is shutting down the restarting, hence the behavior of the red light. Trying to troubleshoot something like this without a schematic is difficult.

Many of the electrolytic capacitors will have critical characteristics and replacing them with caps that are not at least equal can lead to problems ranging from very short life to promptly ruptured caps. Simply going by voltage, capacitance and temperature rating is nowhere near adequate.
 
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Thread Starter

MarioBlacksmith

Joined Oct 5, 2018
2
Wow thank you for all the informative responses!

I am going to go for trying to replace as much capacitors as I can, i just bought most of them.
unfortunately i did not find a schematic for this model, it appears that it is not that popular.

I really appreciate all the information
 
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