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86 posts

Master Geek

Topic # 22737 6-Jun-2008 16:46
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For anyone who has a Philips LCD TV with a backlight that turns off during dark scenes, I recently sent the below email to Philips NZ:

Is there any way to prevent the backlight from turning off when a dark scene is detected? The response time is terrible and the dark scene detection is worse.

Any scene with low light (night scenes, etc) is suddenly plunged into total darkness when the LCD falsely senses that there is nothing on the screen and turns the backlight off. Very distracting. And it's made worse when the scene changes there's a noticable delay before the backlight turns back on. Is there a solution?

Surprisingly someone from Philips rang me back the same day. He said they had received a few complaints about the backlight issue and that he was collecting serial numbers to send overseas to hopefully provoke a response.

So anyone who has a Philips LCD TV with this problem/design flaw - email them your TV's serial number via the Philips NZ website, or ring Barry Ward at the Philips Consumer Care dept on 0800 658 224. Lets bring the power back to the people! :)

My TV model is: 47PFL7422/79 (47" Full HD LCD)


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Mad Scientist
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  Reply # 136032 6-Jun-2008 17:05
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try and turn off any smart/auto/dynamic contrast features. in sony it's called "advanced iris". does pretty much the same thing you described, just not as far as "turn off"... but again as you say, it might be un-turn-off-able, so i guess watch this space!

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Ultimate Geek
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  Reply # 136091 6-Jun-2008 22:15
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I had the same problem with my 52PFL7432/98. I rang Philips and was told that you cannot turn off the dynamic backlight dimming. Fortunately they are wrong it CAN be turned off in the service menu.

Just be aware that you access the service menu at your own risk and adjusting an incorrect setting may damage your set.

To access the menu type "062596" and press "status/info". The service menu should pop up with a SAM in the top right corner. The setting you need to change is in the "Options" menu in "opt 2", which is a byte value representing eight option bits. The possible values for option byte 2 are:

Bit      Dec    Option Name               Description
bit 7   128    1080P                         On = 1080p Available Off = 1080p Not Available
bit 6   64      LIGHT_SENSOR            On = Light Sensore is Available Off = Light Sensor is Not Available
bit 5   32      AMBILIGHT                  On= Ambilight Features Will Be Available Off = Ambilight Features Will Not Be Available
bit 4   16      BACKLIGHT_DIMMING   On = Backlight Dimming is Available Off = Backlight Dimming is Not Available
bit 3   8        HUE                            On = Hue is Available Off = Hue is Not Available
bit 2   4        2D3DCF                      On = 3D Comb Filter is Available Off = 2D Comb Filter is Available
bit 1   2        WSSB                         On = WSS is Available Off = WSS is Not Available
bit 0   1        WIDE_SCREEN              On = TV is 16x9 Set Off = TV is 4x3 Set

So to turn off the backlight diming you will need to subtract 16 from the value of Opt 2. In my case Opt 2 had a value of 157, which means bits 7, 4, 3, 2 & 0 are On (128+16+8+4+1=157). With backlight dimming turned off my Opt 2 value becomes 141.

The picture is so much better with the annoying backlight dimming turned off.

One other great feature in the Service Menu is the ability to adjust the RGB levels, which should allow you to get a fantastic picture.

Hope that helps

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Master Geek

  Reply # 136140 7-Jun-2008 08:42
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joker97: there is a Contrast+ option, have tried turning that off before, it doesn't stop the backlight turning off

rhysb: i entered 062596 then i+, and a big F came up on the top of the screen... i then pressed the menu button and in the menu there was another sub menu named:

47 47LPL_1080_V2.00B 20070711 AP NTSC79

i clicked on that and it went to a screen called FACTORY ADJUST, unfortunately there was no SAM or Options menu from here... most of the available options were adjustable from the standard menu, although there were a few extras like RGB, but definately no backlight_dimming option :(

thanks anyway

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Master Geek

  Reply # 136207 7-Jun-2008 13:22
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update: after learning about the hidden service menus i did a bit more research and managed to download a service manual of a swedish site for $2.

the sad news is it looks like there is no way to turn of the backlight dimming on this model :(

i have uploaded the service manual to rapidshare if any wants to take a look.

i'm still gonna proceed with sending my serial to philips.

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Ultimate Geek
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  Reply # 136493 8-Jun-2008 18:34
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hi i ve got the same tv as u (47PFL7422/79), i like the picture it produces and i get no motion blur  . only  for the dark sences back light,yeah does become a bit annoying and have tryed to  turn it off as well but couldnt
i watched the "alien vs preadtor requiem " on it the other day ,the  back light was dam annoying since the movie is made mainly at night ....
otherwise i am happy with the lcd

i try these setting in this post  and report back ...

please check out my android page on face book do click "like " thanks

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Ultimate Geek
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  Reply # 136641 9-Jun-2008 11:32
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That's a shame it doesn't work for you, the screen dimming can be a real pain.

It looks like your set has a different chassis to mine which has a LC7 chassis.

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Master Geek

  Reply # 136665 9-Jun-2008 14:14
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Yea it sucks to say the least. Mine has a TPT1.2A chassis.

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Ultimate Geek
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  Reply # 136669 9-Jun-2008 14:52
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i rang up phiilps about this issue said we know about it ,and have told phiilps overseas about the issue .went on saying there is no way of turning it of at the moment  ring back in a few weeks to see   if  we have a solution for this ...

well we just have to wait i suppose,not holding my breath on this one

please check out my android page on face book do click "like " thanks

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