TFT Fujitsu x151f: How to reduce brightness?

I take it the controls do actually adjust the brightness, but just not as much as you'd like? If the brightness is clearly excessive, (get a second opinion!) It's possible there's a fault in the backlight inverter, which left could drastically shorten the life of the backlight tubes. There could be excessive voltage to the backlight inverter, or perhaps a failed component on the inverter PCB itself.

If you have electronic skills then perhaps some basic troubleshooting might bring results. If not, either live with it or get it fixed (costly, probably not worth it). You could perhaps try one of those anti-glare screens to reduce the brightness.

If it is working normally but just too bright for your personal tastes, there are ways to reduce the output of backlight inverters, but that is beyond the scope of newsgroup correspondence. An easy 'one size fits all' way which might work could be to lower the supply to the inverter. This may not work well as performance could become intermittent or flickery.

Dave

Look in the menu for a back light brightness adjustment. Some LCDs have two brightness controls. One adjusts the black level of the signal driving the LCD (basically doing the same thing as adjusting it in the video card control panel) and the other adjusts the brightness of the fluorescent tube. You don't want to adjust it with the video card's control panel because you lose a lot of dynamic range. Andy Cuffe

snipped-for-privacy@psu.edu

Dave D wrote: > I take it the controls do actually adjust the brightness, but just not as > much as you'd like?

Yes, you are correct. I'm sure those controls work as manufacturer intended them to work.

I have basic electronic skills, and I'm taking your advice to check if anything is wrong with the backlight inverter or other components.

This matter is really of a personal taste, I think. My eyes just can't adjust to the brightness the monitor emits. If you have any directions (links etc.) to help me with the problem of reducing the backlight inverter voltage, I would appreciate it. That anti-glare screen is my last resort to solve this problem.

Thank you for your response.

:QJD1

Unfortunately, there is no control for black level signal in this monitor, there is only brightness and contrast. I wonder, if there is other ways to control that black level, like dropping the voltages feeding the backlight or otherwise modifying the circuitry.

Thank you for your response.

:QJD1

You may be able to add a variable resistor in the dimming circuit for the backlight inverter, some use a simple pot to adjust it.

How about using a black Sharpie magic marker applied to the tubes themselves?

QJD1 wrote: > I have recently aquired an older second hand TFT monitor, Fujitsu x151f. > Otherwise it works perfectly, but there is one major problem. The > display is far too bright even when the contrast and brightness controls > are turned down to zero. If luminosity is further reduced from the video > card to acceptable elevel, the display starts to flicker. I'm now > looking for methods to reduce the luminosity of this TFT display to a > level, where one can use it and work with it without becoming blind (or > at least without headaches and serious pain in the eyes).

Summary:

Thank You Dave D, Andy Cuffe, James Sweet and JW very much for responding my question with excellent suggestions. I'm sure this problem is part of history quite soon. My options to repair my monitor are now (in that particular order):

1. Acquiring schematics and other relevant information
2. Checking circuitry for defects or faulty components
3. Adding variable resistor (pot) in the dimming circuit
4. Applying black Sharpie magic marker (or similar) to the tubes
5. Mounting anti-glare screen in front of a monitor.

THX + Best Regards

:QJD1

Let us know which solution works for you - that way if someone else comes along with the same question, they might be helped.

Thanks.

"QJD1" bravely wrote to "All" (13 Sep 05 02:56:20) --- on the heady topic of "TFT Fujitsu x151f: How to reduce brightness?"

QJ> From: QJD1 QJ> Xref: core-easynews sci.electronics.repair:341989

QJ> Hello.

QJ> I have recently aquired an older second hand TFT monitor, Fujitsu QJ> x151f. Otherwise it works perfectly, but there is one major problem. QJ> The display is far too bright even when the contrast and brightness QJ> controls are turned down to zero. If luminosity is further reduced QJ> from the video card to acceptable elevel, the display starts to QJ> flicker. I'm now looking for methods to reduce the luminosity of this QJ> TFT display to a level, where one can use it and work with it without QJ> becoming blind (or at least without headaches and serious pain in the QJ> eyes). QJ> Any suggestion to electronically or mechanically make the display QJ> usable is appreciated.

There may be issues with tube biasing. Perhaps some off value resistors or supply voltage. Turning down g2 might do it in a pinch.

A*s*i*m*o*v

... You mean 15" sparks are SUPPOSED to come out of this thing?!?

There may be issues with tube biasing. Perhaps some off value resistors or supply voltage. Turning down g2 might do it in a pinch.

He's talking about TFT monitors ;-)

Dave

I don't know if it counts as a repair, more a mod really!

If it has double tubes top and bottom, you could halve the brightness by simply disconnecting one of each. Cut the connector with a sharp blade to connect one only. When that tube dies, you can just swap to the reserve!

This photo shows a connector cut (to fit a different socket)

You'd need a fairly serious pot to vary that supply, probably a regulator controlled by a pot. You could also connect a PWM signal to the enable/inhibit input on the inverter board for a potentially more reliable result!

Good luck, Alex