PHILIPS 42PFL3704D/F7 no picture

[TimT]

Hi everyone I have a Phillips 42PFL3704D/F7 with no picture. backlight is working. I hear the " tick " when I turn the set on and backlight kicks in just no picture. seems like theres a " blue glow" on screen...but im not 100% sure. I only tested power to power " jack " board getting 11v ac on the 3 pins. any ideas were I should look next?

[RON_CET]

Re: PHILIPS 42PFL3704D/F7 no picture

Check for possible open smd fuse(FP1) on your T-con board located just above and right of your lvds cable which is black cable routing from digital/main board to T-con

[TimT]

Re: PHILIPS 42PFL3704D/F7 no picture

right at 12 volts DC on both ends...bad digital main?

[RON_CET]

Re: PHILIPS 42PFL3704D/F7 no picture

there's also a 3.3 volt voltage feed to the t-con.What is the first few letters on serial#
I need look at schematic

[TimT]

Re: PHILIPS 42PFL3704D/F7 no picture

Serial# 6440y12701778 thanks for your help!

[RON_CET]

Re: PHILIPS 42PFL3704D/F7 no picture

serial number off back TV, should begin with either DS1A,YA1A or DS2A
example YA1AXXXXXXX

[RON_CET]

Re: PHILIPS 42PFL3704D/F7 no picture

also go here http://www.toms-service-manuals.com/ download service manual if you have done so already

[TimT]

Re: PHILIPS 42PFL3704D/F7 no picture

sorry it is DS1A Thanks for the link! downloading it now

[RON_CET]

Re: PHILIPS 42PFL3704D/F7 no picture

when set first powered on do you see the Philips logo come up @ all? Do you have any audio from a viewing channel?If you have no video and backlights are on you should see glow from panel holes from back and also should have slight glow on front but may need low light to notice.Since your confirming voltage on both sides of FP1 fuse next step would be to look at the video signals at the @L3901-3910 on digital/main with Oscilloscope to verify lvds video signals going to the t-con,but not everyone has the scope.Now if you do see the Philips logo then after that no video then i would suspect the digital/main provided you have confirmed that backlights are on

[TimT]

Re: PHILIPS 42PFL3704D/F7 no picture

the back lights are working! I do not see a logo at all on the screen. there is kind of a faint blue glow to it. unfortunately I don't have a oscilloscope to test any further. I think I'll go ahead and order a new digital main since its pretty cheap.

[TimT]

Re: PHILIPS 42PFL3704D/F7 no picture

Replaced digital main still no picture. would a bad T-con cause no sound?

[RON_CET]

Re: PHILIPS 42PFL3704D/F7 no picture

No, Bad T-con would not cause you to loose sound.

[TimT]

Re: PHILIPS 42PFL3704D/F7 no picture

thanks! so problem is with one of the power boards?...im thinking power jack board...main power board seems to be supplying power to it.

[RON_CET]

Re: PHILIPS 42PFL3704D/F7 no picture

im going have say bad T-con when you first turn set on the Philips logo must come up this is control via the digital/main to the T-con. You've indicated your not seeing the logo but you have backlights with glow on screen,you've also confirm smd fuse on t-con good and have 12 volts dc on both sides

[capkid]

Re: PHILIPS 42PFL3704D/F7 no picture

Have you tried connecting an A/V source (DVD player, cable box, etc) to see if you have sound? You'll obviously have to blindly navigate to the input using the remote if the A/V source isn't on the initial input. If you have sound, your T-CON is probably faulty.

[Ltank]

Re: PHILIPS 42PFL3704D/F7 no picture

I had the same TV with it lossing HDMI video and audio both or one or the other randomly. I replaced the Digital board and it has worked fine every time so far. Customer has not picked it up yet. I looked at the schematic audio the RCA jack come from IC803 a
NJM4558M dual audio op-amp to Q703 qnd Q704 KTC3199-GR-AT/P comon emitter transistors.
On the Digital board IC3502 ouputs to the JackPower board to the above Q703/Q704 transistors. IC 3502 ouputs audio to the HDMI Switch IC to the HDMI jacks.
Hope this helps
Ltank

[pdford]

Re: PHILIPS 42PFL3704D/F7 no picture

I have a philips 42 PFL3704D/F7 that was in a lightning storm. I have replaced the main power board. I have sound and a picture if I shine a flashlight at the screen but no backlight. I have 24 Volts on both sides of the fuse on the backlight inverter board.Should I replace the backlight inverter board?

[budm]

Re: PHILIPS 42PFL3704D/F7 no picture

I have a philips 42 PFL3704D/F7 that was in a lightning storm. I have replaced the main power board. I have sound and a picture if I shine a flashlight at the screen but no backlight. I have 24 Volts on both sides of the fuse on the backlight inverter board.Should I replace the backlight inverter board?

But what do you have on BL-ON (INVR-ON), and Dimming control pin?
Pictures of the boards?

[pdford]

Re: PHILIPS 42PFL3704D/F7 no picture

I dont know where those are or exactly how to check them Budm.I have attached a generic pic of the inverterboard in the TV.I know you need better and I will get them on here tomorrow. Thanks for the quick response.

[budm]

Re: PHILIPS 42PFL3704D/F7 no picture

So is that you inverter board?