I've wanted a PowerBook 500 series for ages. So when I actually got given a free 540 recently, I was rather chuffed. It needed a new PSU but when I finally got one, it fired right up. It's a 540 with 12mb RAM and a 250mb hard drive.
However there is a rather weird thing going on with the screen. When it's been on for an hour or so, the corners start to fade. This gradually gets worse and the sides start to fade too. The middle of the screen stays fine and the backlight is nice and bright. If you put it to sleep or turn it off, it gradually gets better, though it takes overnight before it's back to normal. The effect is actually quite cool, it looks like one of those really old TVs or something, and it stays quite usable. Once it's got to a certain point, it doesn't really get any worse.
Anyone got any ideas on what this could be? Apart from that, the machine works fine.
Thanks!
Is the screen getting hot? Overheating from the backlight CCFL tubes might cause LCD trouble.
All PowerBooks with the active matrix grayscale screens can suffer from the malady you describe, it's something many of us who've played with classic 'Books have lamented on a regular basis. There is apparently no cure.
Long ago discussions on the lowendmac PB list included the theory that the LCDs are probably 'leaking' at the edges, with moisture entering and degrading the LCD itself. If anyone has any other informed theories I'd be glad to hear of them.
For some of that long-ago-discussion, search for "corners" or "darken" here.
dan k
Oh well, never mind. I didn't think it would be curable, but I was curious as to the cause. It doesn't really affect what I use it for (a SSH terminal to various servers), so it doesn't matter all that much.