600 LCD brightness

[Wingnut]

I did an extensive search, but couldn't come up with any similar issues. I am trying to fix an old 600 (13" screen) with LCD brightness issues. The slider is very sensitive. To the left the screen is black and to the right its white. Its a very fine adjustment somewhere in the middle where the screen is viewable. But even then, its still dim.

I have changed the inverter & the LCD panel and stil get the same results. Now granted, both were used form another machine, so maybe its a common problem and both machines had issues.

So my question is....is it the backlight or the inverter? The fact that the adjustment range is so wide (from complete black to complete white) it seems like an inverter issue??? All of my other 600's have a very slight screen difference between extreme left & right adjustments on the slider.

Thanks for looking.

[SMA]

The 13" panels used in the early 600's are HPA screens (not TFT).

I have a 600 that does the same, but I have not been digging into its cause.