Thinkpads Forum

My business requires that I travel a lot. My ThinkPad T-60 is a great, dependable notebook (New 06/2007; Model 8743CTO; OS Windows 7 64-bit), and an integral part of my work to say the least. Just within the past several days while flying I began having difficulty seeing the screen. This problem I need corrected ASAP! Based upon my research thus far; is it safe to assume that the culprit is the inverter board? If so, is there some fool-proof way to troubleshoot the problem, and do so quickly?

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In my experience, the inverter board either works or it doesn't. I suppose it could be possible that the inverter's voltage output or oscillator circuit has slightly degraded. The only "fool-proof" way to determine if it is the inverter would be to swap it out and see if there is a measurable difference. The inverter is usually fairly cheap ($8 to $15 on eBay) and it can normally be taken out by removing just the LCD bezel. It could also be that the backlight (aka, CCFL) has suddenly developed a problem. The usual fix in that case would be to replace the entire LCD panel. The harder solution is to just replace the CCFL but that also has some chance of inflicting damage to the panel since you have to disassemble it to get the bulb out. You could end up with a nice bright display but also have some dead pixels or dirt inside the screen.

What you can also do is see if there is a software reason why the screen is dimmer. Go into the BIOS and set the screen brightness to High; Config/Display/Brightness. If you are running the ThinkVantage Power Manager, make sure that you are on Maximum Performance settings. And of course, use the Fn+Home key combination to ensure that the display is set to the highest level.

Running on battery or plugged in?

Many thanks, Ray! Truly, I am grateful. Your three suggestions (Bios, Power Manger, and Fn+Home keys combination) solved the problem. After your explanation I certainly hope the CCFL does not become an issue.

One thing I did not mention in my first post, that is, for about the last three months the T-60 has had a low hum/buzz as soon as it boots up, and it remains constant until the notebook is turned off. Although, I cannot say for sure it seems that the sound is originating from the top (hinge edge) of the notebook in the area of the on/off switch. Is this somewhat common, given its age? This summer the notebook will be three years old, and it receives nearly daily use. Additionally, is this something I should check into now while I am in the states? March 30 I go out of the country again, and I do not want to be in a situation where the notebook goes gown on me entirely.

Humming and buzzing noise can come from two (if not more) areas:

- the inverter board; it has an oscillator as part of its circuitry and an output transformer
- power inductors on the motherboard; these too are similar to transformers (coiled windings)

Normally, when turning down the brightness of the display that can cause the inverter board to make some sounds. Increasing the power load of the motherboard can often make inductors sing a tune. That might occur if you run a program which eats up a lot of CPU cycles (e.g., SuperPI).

From your description of the area that's making the noise, that's probably the inverter.

ref: http://www-307.ibm.com/pc/support/site. ... MIGR-66958 (Hardware Maintenance Manual for 8743 T60)