PowerBook 540c - lower 1/3 of the display is white

[LCGuy]

So I recently picked up a PowerBook 540c. Quite a nice machine...but with one little problem, the display:



After reseating the connections between the interconnect board and display, and switching displays and interconnect boards with my 520c, I've discovered that its the display itself...either the LCD panel or the cable. If I press on the LCD the white part goes black, or makes different patterns, but no matter what I do, I can't seem to get it to come good. Is there any way that I might be able to fix it, or am I stuck with either hunting down a new LCD or cable?

 

[Byrd]

I reckon the TFT panel itself is gone, does any glitching occur when you jiggle the ribbon cables?

For reference's sake, I repaired a 540c the other day - top 50% of screen had vertical stripes (bottom fine) by replacing the inverter board. That repair surprised me, I was so sure it was a dodgy ribbon cable or LCD panel.

 

[LCGuy]

It glitches a bit...I get black and white lines...but it doesn't even come close to giving me a proper image.

Funny you should mention that - upon seeing joe4227's post on doing a similar repair to his 180c I tried switching inverters with the 520c to no avail

 

[Byrd]

That's crap ... you could possibly take apart the layers of the LCD, but the problem is getting it all back together without stuffing up the alignment/dust/fingerprints.

I will be selling my PB540c if interested

 

[LCGuy]

I might be interested, depending on whether I can fix this one...given that 540c panels aren't getting any easier to find, if I can fix this panel and keep one more in circulation that'll make me a happy chappy.

Anyway, its definitely the panel...I pulled the panel apart this morning...if I press on one of the connections on the controller board I can actually make the display come good...I'm wondering if perhaps putting a shim of some kind in there might do the trick.

 

[Byrd]

That's really good news, chances are it can be fixed up

 

[techknight]

You can shim that, but it wont last long. Guarenteed. I tried this a few times on LCD TVs, they dont hold up.

What it is, the actual COF buffer IC is starting to seperate from the ribbon. What model LCD is it? i MAY have it.

 

[Dennis Nedry]

Dastardly thoughts of heat guns and irons are entering my mind - maybe as a last resort.

 

[techknight]

ive tried that too. Wont work.

You can actually see the soldering points where the flex cable is put on the PCB, what you have to look for is if you peel off the kapton tape, you can see the copper is tearing or has torn away from the ribbon.

If the panel to ribbon connection is ok, and if the buffer IC is not separating the ribbon, and its ONLY the broken copper tracks coming off the end of the ribbon to PCB, then MAYBE pressure would hold over time. Otherwise it will not.