42pfl5432d/37 no picture but have sound

[dsm482]

Hi,

ITs Phillips

42pfl5432d/37 no picture but have sound

I got a questions for the TV.. Where is the last guy that runs this forum he helped me last time..

I got no picture , but I do have sound.

I took the TV apart..

Inverter boards look good no Caps blown.

Also Power supply looks decent with the caps, they were replaced once.

I checked power at inverter board , the main and slave both get 24.9 volts steady power.

Tcon board above I looked at looks good.

The Main board was replaced with new unit from broken TV new.
Looks like new, and HDMI ports are like new.


Touch confused, why I dont have picture and nothing is pooping out at me?

Any suggestions??

[dsm482]

Re: 42pfl5432d/37 no picture but have sound

does the Tcon on these have a fuse?

Inverter board fuse location?
Is it F1 on main inverter board.?? that one has 24V on both sides.

[dick_barton]

Re: 42pfl5432d/37 no picture but have sound

Photo's of your circuit boards could help answer some of your questions.

[dsm482]

Re: 42pfl5432d/37 no picture but have sound

Ok here are the pictures..

The power supply board had the caps replaced and is powering 24v to inverter boards.
Those burn that look like diodes, were supposedly checked from a TV repair... I assume power Supply is good, since I got power going to Tcon and inverters.


Inverter Board Test I did.
Main and Slave are getting 24V confirmed at the pin connector.

On the Main I found one fuse F1 that one gets both sides 24v

I cant located the other fuses, there should be 2 on each inverter board according some posts. Help?
I really need to locate these since that would make sense the inverter boards are bad

TCon board test I did. these are the pinholes

Gnd =0V
SDA= 3.32V
VIN= 12.20V
SCL= 3.30V
TSTPGM= 0V

I also loacted
Voltage Regulator AME 8815 AECS 250 0733

I listed the pins from top of TV downward.
Pin 1= 2.49V
Pin 2= 0V
Pin 3= 3.28V

Dont see the other one some have two with three pins on mine Tcon I only see 1.


any help appreciated.

[R_J]

Re: 42pfl5432d/37 no picture but have sound

You likely have a bad inverter or maybe a bad ccfl, Just because you have 24 volts going to the inverter, doesn't mean it is working. Start by checking the inverter transformer secondary resistance and compare the readings to see if one is different.

[dsm482]

Re: 42pfl5432d/37 no picture but have sound

you need to point to me so I can test it.
whats a CCFL?

I don't have schematics..
am engineering tech not TV repair specialist ))

[R_J]

Re: 42pfl5432d/37 no picture but have sound

you need to point to me so I can test it.
whats a CCFL?

I don't have schematics..
am engineering tech not TV repair specialist ))

Do you drive the train?
Cold Cathode Florescent Lamp

[dsm482]

Re: 42pfl5432d/37 no picture but have sound

ok,

no actually I am electro/mechanical)
no trains,
you can use AMTRACK..


location of those?
CCFL the lamp
and

where do I check inverter transformer secondary resistance..

Arent there fuses on the inverter board???also

[R_J]

Re: 42pfl5432d/37 no picture but have sound

The ccfl's are what produce the light so you can see the picture, they are located in the panel behind the lcd screen
The transformers are those large black components connected to the white connectors that connect to the ccfl's in the panel. Now this is with the TV unplugged... Check the resistance (ohm meter) of the transformer at the connections that go to the white plugs.

[dsm482]

Re: 42pfl5432d/37 no picture but have sound

so disconnect the connector, the white one..obviosly TV unplugged.
Resistance test..
I am not that dummy

[R_J]

Re: 42pfl5432d/37 no picture but have sound

Have you tried shining a flashlight at the screen to see if you can see an image? or do you have backlights? or do the flash on for a second then go out?

The T-Con does have a fuse, it is near the lvds cable labeled FP1, Check the voltage on both sides of the fuse

[dsm482]

Re: 42pfl5432d/37 no picture but have sound

there is 10 on each inverter board.
Disconnect them.

Check resistance from the CCFL thats wires going to TV panel right?
Then check the resistance of each black transformer same plug at panel boad inverter side
Right?

[R_J]

Re: 42pfl5432d/37 no picture but have sound

First check if you can see a faint picture on the screen while shining a flashlight (or other light) on the screen, (when the tv is on and you can here sound) If you can see a picture, then you know the t-con is working,
You can check if the T-Con is getting voltage at the fuse (labeled FP1)

[budm]

Re: 42pfl5432d/37 no picture but have sound

There are FIVE fuses on the Master inverter board,
F1 is a small Black fuse 0.75A 76V.

F101, 102, 103, and 104 are White fuses 3A 63V, there are loacate next to each one of the black Lytics caps.

Slave Inverter board also has Four White fuses F201, 202, 203, and 204 next to each black lytics caps.

Pictures provided by SHOPJIMMY.

[dsm482]

Re: 42pfl5432d/37 no picture but have sound

I tried flashing a light didnt see anything.
Ccfl going to panel i unhoked the white connector from inverter board.
Resistance to panel is open on all of them.
Resistance to inverter board side connector is at 5.7-5.9 range on all of them both sides

[R_J]

Re: 42pfl5432d/37 no picture but have sound

If you didn't see any image using a flashlight, it could be that the T-con is not working, Check the voltage on the T-con fuse.
Also check the fuses on the inverter boards as budm suggests

[dsm482]

Re: 42pfl5432d/37 no picture but have sound

Did you read my answer for resistance on ccfl?
How i did it.
And the values?
Open on side of wire going to panel

Voltages
Tcon fp1 fuse both sides 12v

Main inverter board
F1 fuse 24v both sides
F101 18.3v to 18.6v both sides
F102 18.5v to 18.5v both sides
F103 18.6v to 18.7v both sides
F104 18.8v to 18.6v both sides


Slave inverter board
F201 24.8v to 24.8v both sides
F202 25v to 25v both sides
F203 25.1v to 25v both sides
F204 25.3v to 25.3v both sides

[dsm482]

Re: 42pfl5432d/37 no picture but have sound

I broke a sweat, trying to test all thise values
sorry for typos
I had to use my cell phone.
Internet died from spectrum wtf

[budm]

Re: 42pfl5432d/37 no picture but have sound

Did you read my answer for resistance on ccfl?
How i did it.
And the values?
Open on side of wire going to panel

Voltages
Tcon fp1 fuse both sides 12v

Main inverter board
F1 fuse 24v both sides
F101 18.3v to 18.6v both sides
F102 18.5v to 18.5v both sides
F103 18.6v to 18.7v both sides
F104 18.8v to 18.6v both sides


Slave inverter board
F201 24.8v to 24.8v both sides
F202 25v to 25v both sides
F203 25.1v to 25v both sides
F204 25.3v to 25.3v both sides

Those fuses are fed by 24V so they all should be showing 24V, not 18V. May be recheck your measurement again.

[R_J]

Re: 42pfl5432d/37 no picture but have sound

ccfl's are florescent tubes, they will not measure any resistance, As for the transformer resistance 5.7-5.9 ? is this Ω or KΩ. If they are all the same then they are likely ok.
Usually even if the t-con or the lcd has an issue the backlight should still work.

You say the main board was replaced, was the tv working with the new main board and now you have this issue or did the tv fail and you replaced the main board and still have this problem?

Main inverter voltages are low? like budm says they are fed from the 24 volts so should also read 24v
There is also another smd fuse on the main inverter board (near the white plug's legend) 0.75A/76V (labeled 15?)