Phillips LCD Model #42PFL7422D/37

[Tayninh55]

Phillips LCD Model #42PFL7422D/37
I have this 42” tv, Phillips LCD Model #42PFL7422D/37, when you plug it in, it shows a solid blue power light, black screen (nothing on the screen), and then makes a clicking sound for a while, then shuts down (with no power light). I thought wow, easy fix, probably bad caps. Took the back off, cannot see any visible signs of bad caps (no bulging or leakage visible). I then plugged it in and turned it on to see where the noise was coming from, could see two different places that lit up and went back off with the clicking sound, on the main board. The noted lights (on the main board) came on and off with the clicking sound. Haven't checked anything else yet. Just took “my pictures” and quit for the night. Appreciate a little guidance as I'm not trained in this field, just trying to pick up a little knowledge as a hobby. Thanks!

[Tayninh55]

Re: Phillips LCD Model #42PFL7422D/37

Will this move my post to the top of the page?

[maxvalutech]

Re: Phillips LCD Model #42PFL7422D/37

You have standby voltage and tv is trying to turn on. You need to take all the voltages as shown near connectors on Power board and post the readings together with what the markings say e.g. ps-on etc.

[Tayninh55]

Re: Phillips LCD Model #42PFL7422D/37

Thank you for the info,,,,,,,,,,,,,,do you mean put the black lead on a ground (where a screw holds the board down) and then check each point where a wire leaves the power board thru the connectors with the red probe and record the voltage,,,,,,,,,,,with the unit plugged in?

[dskall]

Re: Phillips LCD Model #42PFL7422D/37

Yes and when powered on.

[Tayninh55]

Re: Phillips LCD Model #42PFL7422D/37

Hi,,,,,I just got back to my tv. I checked for power at the ribbon that goes from the power board to the main board (with everything connected) and found no dc voltage at any of the pins. When I plug in the AC cord, the green lights (standby voltage, I guess) come on and the blue power light comes on. Then the green lights on the main board go out, and the blue power light goes out and turns to a red blinking light of six long and three short blinks. I had my wife plug it in, and there is still no dc voltage at that ribbon with the green lights burning on the main board. What does six long blinking red lights, followed by three short red blinking red lights indicate? Thanks!

[dskall]

Re: Phillips LCD Model #42PFL7422D/37

What connector did you check?
Need voltages from connector that goes from power supply board to main board. Will need pin#-pin label-Pin voltage in standby-Pin voltage when pushing power button and picture of connector on power supply board.
Format:
Pin# - Pin Label - Pin Voltage standby - Pin voltage power on
1 - XXXXXXX - XXv - XXXv
2 - XXXXXXX - XXXv - XXXv
3 - XXXXXXX - XXXv - XXXv
4 - etc.

[budm]

Re: Phillips LCD Model #42PFL7422D/37

We need the pictures of the whole backside of the TV showing all the boards and how they are connected together.
You have two power supplies, the standby supply is on the main board, and then you have main power supply that is turned on by the main board.
There are many version of this model so we need to know what trhe actual boards are being used in your TV.
http://www.shopjimmy.com/catalogsear.../?q=42PFL7422D

[Tayninh55]

Re: Phillips LCD Model #42PFL7422D/37

Seems like there were a lot of numbers on these boards: On the power board was 3104 303 50594 Then on a sticker was ES 730.3 002.C 0011407 and S310432848912 284912
Then on the main board: 3104.303.50842 D and 8204.004.58882 Hope these are what you need.
DISREGARD MY %6 post, I had a ribbon cable disconnected and did realize it at the time. My symptoms are still the same as in my first post.

[Tayninh55]

Re: Phillips LCD Model #42PFL7422D/37

OK,,,,,,here are the pictures of the back of the tv,,,,,,

[Tayninh55]

Re: Phillips LCD Model #42PFL7422D/37

It seems that most of the pins on these boards are not labeled. I plugged it in,,,,,the green lights (standby voltage?) came on for a couple seconds,,,,,then went off. I measured the voltage on the ribbon that goes from power board to main board AT the edge of the power board.
Pin furthest to the left I'll call #8 on the pic of the top of the board,,,,,,#8 pin will be the furthest to right on the pic of bottom of the board.

#8 0 Voltage
#7 0
#6 0
#5 0
#4 0
#3 4.0 Volts
#2 5.0 Volts
#1 0.1 Volts

[budm]

Re: Phillips LCD Model #42PFL7422D/37

Can I see the model number sticker on the back of the TV? I need the chassis number on that sticker.

[budm]

Re: Phillips LCD Model #42PFL7422D/37

https://www.badcaps.net/forum/attach...3&d=1490296060

Check the resistance of the resistor R3318 which is right next to the gray rectangular cap, you also need t check the capacitance of that grey cap.

[Tayninh55]

Re: Phillips LCD Model #42PFL7422D/37

OK,,,,,,here's the sticker on the back.

On the resister, can I just release one end of the resistor to check it,,,,,or should I take it out of the board completely?

On the capacitor, should I check it with the power plugged in, for DC voltage, and if so, how do I tell the polarity on it (don't think I've ever checked one like that before) I didn't check closely, but don't remember seeing polarity,,,,,I'll check again.

Thanks again for the guidance!

[budm]

Re: Phillips LCD Model #42PFL7422D/37

You can test it without removing the resistor, that resistor usually goes open circuit when it is bad, it usually has the value between 47~150 Ohms.
The grey cap that the resistor is connected to usually lose its capacitance.

[budm]

Re: Phillips LCD Model #42PFL7422D/37

OK,,,,,,here's the sticker on the back.

On the resister, can I just release one end of the resistor to check it,,,,,or should I take it out of the board completely?

On the capacitor, should I check it with the power plugged in, for DC voltage, and if so, how do I tell the polarity on it (don't think I've ever checked one like that before) I didn't check closely, but don't remember seeing polarity,,,,,I'll check again.

Thanks again for the guidance!

OK, so it is 42PFL7422D/37 chassis # Q523.1U LA.
I will see if they have the service manual at elektrotanya.com

[Tayninh55]

Re: Phillips LCD Model #42PFL7422D/37

I think you were right about that resister. When I checked it on 200 ohm scale, it flashed a number, then went to the 1 at the left of the scale, indicating that it's open. I have a continuity checker that beeps. Touch the probes together, and it beeps,,,,,,,,put a probe on each end of the resistor,,,,,and nothing.

Not sure on the capacitor. Put meter on the 2000k scale and it started out at about 800, and slowly the numbers continued going up.

[budm]

Re: Phillips LCD Model #42PFL7422D/37

Can you read the resistance as printed on that resistor?
To check the capacitor you will need to check the capacitance, I do not know if your DMM can do capacitance reading or not.

[budm]

Re: Phillips LCD Model #42PFL7422D/37

OK, R3318 per Q523.1U LA chassis, it is supposed to be 470 Ohms.

[budm]

Re: Phillips LCD Model #42PFL7422D/37

BTW, this model is also known for having blown IC on the inverter boards and they need the modification:
https://www.badcaps.net/forum/showth...ght=42PFL7422D