philips 42pfl7422d white screen

[vibac123]

hi guys,
i have this question with my tv. i am not an electrician or something. i don't even know how to use the tester. lol. all i know it how to open and replace stuff. lol. i just wanted to ask you guys about my it was working out fine then it started to show very bright light and the images are so faint. i can still see some of the images at the screen though but it's just to bright. now will i change the SSB or the t-con board? because all i see in the SSB are 3 of the 5 LED lights are on. thats just it. i know its a very dumb question, please help me out guys. don't want to just throw this away. here are some pictures.

Thank you

Mariane

[tom66]

Re: philips 42pfl7422d white screen

We've seen this before. It usually turns out to be the T-Con board. If we get a picture of the chassis (overall image) we can help you locate this. Also, what is the chassis code of your TV? For example LC4.41-AB. It's on the model # sticker, in a box marked "S".

[vibac123]

Re: philips 42pfl7422d white screen

Thanks tom66 i am attaching here the picture of the whole back of the tv and the sticker of the back cover too. so the t-con board is the culprit? because i have buds guide to troubleshooting lcd tv's and still it confuses me whether or not its the t-con or the ssb. before it was like this though it had some green lines on one part of the screen and a little pink hue. is this definitive of the t-con malfunctioning?

thank you so much tom66

[budm]

Re: philips 42pfl7422d white screen

Where are the pictures? The way you described the picture on the screen, it sounds like the GAMMA circuits are not working (not getting the correct voltage, not 100% sure though.

[vibac123]

Re: philips 42pfl7422d white screen

Thanks tom66 i am attaching here the picture of the whole back of the tv and the sticker of the back cover too. so the t-con board is the culprit? because i have buds guide to troubleshooting lcd tv's and still it confuses me whether or not its the t-con or the ssb. before it was like this though it had some green lines on one part of the screen and a little pink hue. is this definitive of the t-con malfunctioning?

thank you so much tom66

[budm]

Re: philips 42pfl7422d white screen

Do you see the small CAUTION sticker at about bottom center of the chassis picture, next to it is a flat connector to the board that is under the metal chassis? That is the T-CON board, this will be hard to work on since you will not be able to access the board to make the voltage measurement.

[vibac123]

Re: philips 42pfl7422d white screen

Do you see the small CAUTION sticker at about bottom center of the chassis picture, next to it is a flat connector to the board that is under the metal chassis? That is the T-CON board, this will be hard to work on since you will not be able to access the board to make the voltage measurement.

thanks bud! but the problem is i don't know how to measure them lol. i can open and replace stuff but not so much on the tiny bits especially electricity stuff. So the t-con board is the culprit bud? sorry for being such a newbie.

mariane

[budm]

Re: philips 42pfl7422d white screen

We cannot be 100% sure until we can take some voltage readings first, even that will not be 100% for sure, if the T-CON is cheap enough, you can try a new one, but you will need to get correct number as printed on the sticker of the T-CON board.

[vibac123]

Re: philips 42pfl7422d white screen

hi bud,
i managed to take the tcon board out of the tv. Is it okay if i ask where and what part of the board i need to test? i have a tester here though but i don't know where to set it.

thank you

Mariane

[tom66]

Re: philips 42pfl7422d white screen

The parts for these boards generally aren't available in low quantities, but you can still test parts to determine the cause of the problem.

There's a long set of pins labelled VGMA1 thru VGMA22. Please measure each pad. Set your multimeter to volts DC (20V range) and make sure the red probe is in the V/ohm socket, black probe is in COM. Place the black probe on the chassis of the TV. Power up the TV and play a video. Measure each voltage on VGMA1 thru VGMA22. You should see a steady increase or decrease from one voltage to another.

[vibac123]

Re: philips 42pfl7422d white screen

The parts for these boards generally aren't available in low quantities, but you can still test parts to determine the cause of the problem.

There's a long set of pins labelled VGMA1 thru VGMA22. Please measure each pad. Set your multimeter to volts DC (20V range) and make sure the red probe is in the V/ohm socket, black probe is in COM. Place the black probe on the chassis of the TV. Power up the TV and play a video. Measure each voltage on VGMA1 thru VGMA22. You should see a steady increase or decrease from one voltage to another.

hi tom
i was able to test them from 1-22 and there was a steady decease in voltage. Does this mean that it's still functioning as it should be?

[vibac123]

Re: philips 42pfl7422d white screen

here are the readings tom.

[tom66]

Re: philips 42pfl7422d white screen

Those voltages indicate the gamma IC is functioning correctly.

I've highlighted some more checks.

If these pass the problem may be with the large AU Optronics controller chip, which would be impossible for the average user to replace (plus it's probably difficult to source.) So a new T-con would be the best way to fix it.

I note that it is available starting from $25.00 from several sellers.
http://www.ebay.com/sch/i.html?_trks...t=0&_from=R40#

The one thing you must be sure of doing when you replace it, is to transfer those beige heat pads to the new board.

[flocko]

Re: philips 42pfl7422d white screen

Hi the photo in post 5 looks like the the lead from the av board to to t-con is not in all the way on the av board

[vibac123]

Re: philips 42pfl7422d white screen

Those voltages indicate the gamma IC is functioning correctly.

I've highlighted some more checks.

If these pass the problem may be with the large AU Optronics controller chip, which would be impossible for the average user to replace (plus it's probably difficult to source.) So a new T-con would be the best way to fix it.

I note that it is available starting from $25.00 from several sellers.
http://www.ebay.com/sch/i.html?_trks...t=0&_from=R40#

The one thing you must be sure of doing when you replace it, is to transfer those beige heat pads to the new board.

hi tom,
i got the reading now. there was only one though that had 1. as a result. what could that one mean? i have the pic attached.

thank you

[retiredcaps]

Re: philips 42pfl7422d white screen

hi tom,
i got the reading now. there was only one though that had 1. as a result. what could that one mean? i have the pic attached.

If you are getting a "1" on the left hand side of your manual range multimeter, it means the voltage is > 20V DC. Set your multimeter to 200 DC and retest that one area. You should get reading between 20 and 200V DC instead of "1".

A multimeter tutorial.

http://www.sparkfun.com/tutorials/202

[tom66]

Re: philips 42pfl7422d white screen

3.4V is OK on 3.3V.

Follow retiredcaps advice about the metering of the "1 ." pad.

And there is one further pad I forgot to ask you to test: V2D5, it's near V1D8. I expect 2.4~2.6V.

[vibac123]

Re: philips 42pfl7422d white screen

If you are getting a "1" on the left hand side of your manual range multimeter, it means the voltage is > 20V DC. Set your multimeter to 200 DC and retest that one area. You should get reading between 20 and 200V DC instead of "1".

A multimeter tutorial.

http://www.sparkfun.com/tutorials/202

thank you this helped alot.

[vibac123]

Re: philips 42pfl7422d white screen

3.4V is OK on 3.3V.

Follow retiredcaps advice about the metering of the "1 ." pad.

And there is one further pad I forgot to ask you to test: V2D5, it's near V1D8. I expect 2.4~2.6V.

hi tom,
i checked the V2D5 and i got 2.49v in it. So probably the chip is the broken one right tom? Or is there a possibility that the SSB is the one that is broken or is it highly unlikely? What about those 3 out of 5 LEDs lighting up tom? Is it normal for it to be like that?

thank you