Brand new inverter dead?

[gardar]

So I just bought a new inverter for my T42 since the old one was dead, after few successful startups with the new one it's begun to make a high pitched noise (reminds me of farad noise) and the brightness of the screen approx 2seconds after turning the laptop on.

Could there be something causing this? Or was I just unlucky with the new inverter?

[ajkula66]

If your CCFL as at the end of its lifespan, it might cause an inverter to prematurely fail.

Any redness on that screen?

[gardar]

Nope, no redness.

Anyways I'm upgrading to LED so I don't have to worry about the CCFL or inverter anymore. I was just wondering if there could be anything like a bad motherboard or connectors that could be causing the inverter to fail.

[RealBlackStuff]

How are you going to get your other System LEDs (HD, Numlock, WiFi, BT, etc.) going without an IBM inverter?

[gardar]

The system leds on the inverter work fine, it's just the backlight that goes out after approx 2secs.

I'll solder the backlight led controller to the inverter, if that doesn't work I'll have to solder it to the wires before they go in the inverter, hopefully the backlight led controller leaves enough power to power the system leds on the inverter.

[RealBlackStuff]

AFAIK you will keep using the standard LCD cable.
The only thing that changes is that CCFL-backlight power (up to 1200V) is no longer connected to the inverter.
The power for the LED-backlight (5-20V) probably also comes from the inverter, unless your "construction" comes with its own controller board.
Where does that board go?

[rkawakami]

RBS: I'm on LCDPARTS mailing list and received this information last week: http://www.lcdparts.net/howto/MS492LEDD.aspx

Apparently one is supposed to solder three wires onto the inverter board, tapping the appropriate power and control signals. The LED driver module is then supposed to mount to the back of the LCD panel ("It is so small and thin that it can be actually mount on the back of LCD screen"). Not so sure about that part... Also according to them, you may lose control over dimming the display as they say Lenovo inverters use PWM (pulse width modulation) to adjust the brightness, as opposed to an analog control.

[twistero]

Also according to them, you may lose control over dimming the display as they say Lenovo inverters use PWM (pulse width modulation) to adjust the brightness, as opposed to an analog control.

Huh. In that case, lcdpart's offering has less functionality than this Chinese guy's http://shop57917463.taobao.com/shop/vie ... b3d19c.htm
This LED mod retains the dimming functionality.

[RealBlackStuff]

Thanks Ray,
I foresee a nice pressure spot if one uses that (overpriced) lcdparts conversion kit.
I'm playing with a LED-backlit LCD in a 15" T60, where I got it working perfectly. I'm NOT using that conversion kit...
My next trial is the same screen in a 15" T4x.

[AGoodSolution]

The system leds on the inverter work fine, it's just the backlight that goes out after approx 2secs.

I'll solder the backlight led controller to the inverter, if that doesn't work I'll have to solder it to the wires before they go in the inverter, hopefully the backlight led controller leaves enough power to power the system leds on the inverter.

What you're describing sounds like an issue I'm familiar with, after powering on the system, do have you tried rapidly clicking the lid closed switch in the upper left corner of the deck, right at about 1:00 PM of the ESC key?

Flicking that switch a few times, will the LCD backlight flicker back on ?

If so, that is a shot CCFL, since flicking that button seems to make the LCD come back to life, it is often assumed replacing the LCD cable (no easy affair) will solve the matter but it rarely does. Sometimes it may be the LCD inverter and for their insignificant cost and easier to replace, it may be worth trying a new inverter.

But more frequently, when I see what you're describing, the backlight is gone.
Flicking the close lid switch with a toothpick or something else appropriate and non metal cuts and re-engages the power to the LCD backlight and momentarily sends a surge of volts to reinvigorate the dying LCD the way you can make a comatosed patient jump out of the bed with defribilators.

[RealBlackStuff]

And LCD-switches have also been known to die!
If it is broken and you don't need it, just remove it and solder a short wire across its old contact points, then insulate that.