Inverter mod for Philips 47PFL7422 to disable dynamic backlight?

[budm]

Re: Inverter mod for Philips 47PFL7422 to disable dynamic backlight?

Brightness control is not the same as backlights level control.
I just look up the user manual, there is no backlights level control for this model.
There is the CONTRAST + which there is no explanation to what they are for.
May be this is what it is for:
https://cdn.badcaps-static.com/pdfs/...7e3a209c66.pdf
Dynamic contrast enhancer
You want the LCD flat display with the highest
contrast and most vibrant images even at wide
viewing angle. The Philips dynamic contrast
enhancer uses video processing and unique
dimming backlight technology. This delivers
deep rich black levels with increased detail.
The dimming backlight increases the contrast
up to 5 times*, and at the same time improves
the viewing angle. It gives a bright, lifelike
picture with high contrast and vibrant colors,
(* factor between 2 and 5, scr.

So you are correct that if you want to be able to adjust the backlights level then I would use DC DIMMING control but then the user has to be able to set it some how since it is not adjustable in the user menu.

[Agent24]

Re: Inverter mod for Philips 47PFL7422 to disable dynamic backlight?

I believe if you disable on pin 11, the dimming function on the user menu backlights setup level will still work.

That's the thing - the user menu brightness control doesn't adjust the backlights at all. It only seems to adjust the image gamma or some other property. The backlights stay at full brightness.

[budm]

Re: Inverter mod for Philips 47PFL7422 to disable dynamic backlight?

I believe if you disable on pin 11, the dimming function on the user menu backlights setup level will still work.

[Agent24]

Re: Inverter mod for Philips 47PFL7422 to disable dynamic backlight?

I've got a basic idea from the photos, I think. Need to confirm and see where the rest of it goes, but it looks like I can probably just disable the TCON dynamic control with the LVDS connector Pin 11 and then put in my own analog signal on I-PWM, switched on only when the E-PWM signal is present from the mainboard to keep the timing right.

I think I might try checking those signals with a logic analyser to see what turns up, but I reckon I just need a pulse stretcher fed by the mainboard's PWM signal which will mean a constant high output as long as the PWM signal exists, then drive an adjustable resistor divider and output my own, adjustable analog voltage to the inverter's I-PWM pin. (easier than making my own PWM signal)

[budm]

Re: Inverter mod for Philips 47PFL7422 to disable dynamic backlight?

I'm looking for the resource or website that contains panel specifications for many makes and models.

This is one of them:
http://www.beyondinfinite.com/library.html

Or just search the web using the panel number, that is what I do.

[Agent24]

Re: Inverter mod for Philips 47PFL7422 to disable dynamic backlight?

I don't know if there is one. I just Googled the part number that was on the LCD panel's sticker. It was the first result as a PDF file.

Might be able to try some of the ideas and check more things on the TV this weekend.

[mmartell]

Re: Inverter mod for Philips 47PFL7422 to disable dynamic backlight?

Not sure what you mean

I'm looking for the resource or website that contains panel specifications for many makes and models.

[budm]

Re: Inverter mod for Philips 47PFL7422 to disable dynamic backlight?

This TV uses Global dimming topology.
"Backlight global dimming method dims the whole
backlight by a universal factor in each frame, Figure 1(a).
This method is mainly used to reduce power
consumption [1] or improve dynamic contrast"

[tom66]

Re: Inverter mod for Philips 47PFL7422 to disable dynamic backlight?

The T-con signal, I believe, is used only to flash the backlight at the same rate as the T-con updates, this helps reduce motion blur by making the LCD black during updates, the eye only sees complete images (in theory.) The T-con does not control dimming on these sets. I would try just wiring E-PWM to 100% permanently (e.g. to BL ON/OFF) with a resistor, say 100 ohms or so, and see if that works.

[fzabkar]

Re: Inverter mod for Philips 47PFL7422 to disable dynamic backlight?

Some resources ...

OZ9928SN application circuit and datasheet (?):
http://www.520101.com/html/circuitry/153257993.html
http://www.docin.com/p-259604310.html
http://webcache.googleusercontent.co...259604310.html

OZ9928SN application circuit (poor quality, but readable):
http://www.520101.com/files/otherima...5324052476.jpg

OZ9938GN datasheet and application circuit (some similarity to OZ9928SN):

OZ9928SN PIN DESCRIPTION 

Pin Name   Description 

1  SSTCMP2  Soft start and compensation for controller 2
2  ISEN2   Lamp current sense for controller 2 
3  VSEN2   Transformer output voltage and over-current detection for controller 2 
4  ISEN1   Lamp current sense input for controller 1 
5  VSEN1   Transformer output voltage and over-current detection for controller 1 
6  ENA    OZ9928 on/off control 
7  SYNC   Operation frequency sync signal input 
8  VIN    Power 
9  VREF   Reference voltage 
10 LDR1   Low side driver for controller 1 
11 LDRC   Low side driver for controllers 1 and 2 
12 PGND   Power GND 
13 LDR2   Low driver for controller 2 
14 LX1    High side N-Channel power MOSFET source for controller 1 
15 HDR1   High side power MOSFET driver for controller 1 
16 BST1   High side driver boost voltage for HDR1 
17 BST2   High side driver boost voltage for HDR2 
18 HDR2   High side power MOSFET driver for controller 2 
19 LX2    High side N-Channel power MOSFET source for controller 2 
20 BSTC   High side driver boost voltage (HDRC) for controllers 1 and 2 
21 HDRC   High side power MOSFET driver for controller 1 and 2 
22 LXC    High side N-Channel power MOSFET source for controllers 1 and 2 
23 GNDA   Signal GND 
24 CT    Timing capacitor and resistor setting for operation and striking frequency 
25 RPT    Sync signal output for master mode. Connect to GND for slave mode. 
26 LCT    Timing capacitor and resistor setting for low frequency oscillator 
        or external PWM pulse input. 
27 DIM    DC voltage for PWM dimming or analog dimming. 
28 TIMER1  Striking and shutdown delay timer for controller 1 
29 TIMER2  Striking and shutdown delay timer for controller 2 
30 SSTCMP1  Soft start and compensation for controller 1

[budm]

Re: Inverter mod for Philips 47PFL7422 to disable dynamic backlight?

What happen if you remove the flat ribbon cable from the T-CON? That cable is for the control signals to control the inverter board.
Otherwise you can try GND that control pin.

[tom66]

Re: Inverter mod for Philips 47PFL7422 to disable dynamic backlight?

ShopJimmy seem to be adopting the rather bizarre practice of blocking non-US IP addresses. I guess they see us as non-customers, but it's bad because I can no longer recommend them on this forum.

[fzabkar]

Re: Inverter mod for Philips 47PFL7422 to disable dynamic backlight?

Does anyone else have a problem with that link? I'm getting this error:

Access Denied
You don't have permission to access "http://assets.shopjimmy.com/media/catalog/product/cache/1/image/f8f28dc4a19c21aeb55ee5774693fb5d/s/h/shopjimmy-35-d020223-top_2.jpg" on this server.

Reference #18.737e1cb8.1442871383.f9ca5f9

Works OK for me.

[Agent24]

Re: Inverter mod for Philips 47PFL7422 to disable dynamic backlight?

Also just to 'chirp in' you might want to consider recapping that psu noticed capxons on there, them power boards if the caps fail will kill the Pfc and cause a failure of chirping sound psu which is hard to repair.

Are they? I didn't notice!

[Agent24]

Re: Inverter mod for Philips 47PFL7422 to disable dynamic backlight?

See page 15, LVDS connector pin 11 (NOTES 6) is for Dynamic contrast, HIGH = ENABLE, LOW = DISABLE.
So that means you may be able to disable this function in the user setup menu since this pin goes to the main board so it is can be set by the main board to turn it on or off.

According to my friend, and others who posted on Geekzone, there is no option to turn the dynamic backlight control off in software, with either the user or service menu. I can check it out myself but I'm pretty sure that's the case.

But, I wonder if I could just disconnect Pin 11 to the T-CON from the mainboard and tie it to ground instead? I suspect though that there would also need to be a change in the E-PWM signal from the mainboard as well, unless one can override the other. Perhaps I should try that and see what happens...

If that doesn't work, I suppose I could float E-PWM and use I-PWM instead (datasheet says to use one, float the other), but it looks like the timing would need to be taken into account. Seems either E\I-PWM signal has to come up before BLON does, go low before BLON goes low, and BLON has to wait at least 1ms after VBL comes up or before power down.
I'd probably have to use the PWM signal from the mainboard to switch the output to I-PWM via some custom circuitry to keep the timing somewhat correct.
Or am I over-thinking this?

http://assets.shopjimmy.com/media/ca...0223-top_2.jpg

There is no info of the CON1 of the T-CON board which goes to the Inverter board, you can see the pins DIM_I, and DIM_0.

Does anyone else have a problem with that link? I'm getting this error:

Access Denied
You don't have permission to access "http://assets.shopjimmy.com/media/catalog/product/cache/1/image/f8f28dc4a19c21aeb55ee5774693fb5d/s/h/shopjimmy-35-d020223-top_2.jpg" on this server.

Reference #18.737e1cb8.1442871383.f9ca5f9

[budm]

Re: Inverter mod for Philips 47PFL7422 to disable dynamic backlight?

See page 15, LVDS connector pin 11 (NOTES 6) is for Dynamic contrast, HIGH = ENABLE, LOW = DISABLE.
So that means you may be able to disable this function in the user setup menu since this pin goes to the main board so it is can be set by the main board to turn it on or off.
http://assets.shopjimmy.com/media/ca...0223-top_2.jpg

There is no info of the CON1 of the T-CON board which goes to the Inverter board, you can see the pins DIM_I, and DIM_0.

[ReeceyBurger123]

Re: Inverter mod for Philips 47PFL7422 to disable dynamic backlight?

Also just to 'chirp in' you might want to consider recapping that psu noticed capxons on there, them power boards if the caps fail will kill the Pfc and cause a failure of chirping sound psu which is hard to repair.

[Agent24]

Re: Inverter mod for Philips 47PFL7422 to disable dynamic backlight?

Where is the panel lookup ?

Not sure what you mean

[mmartell]

Re: Inverter mod for Philips 47PFL7422 to disable dynamic backlight?

Where is the panel lookup ?

[Agent24]

Re: Inverter mod for Philips 47PFL7422 to disable dynamic backlight?

I found the panel datasheet, will read it later.