PowerBook 540c LCD "Grid"

[wally]

Okay, while cooking dinner I sucked in 1 MB and looked at it. I notice you have solid blacks and solid whites with no pixel light leakage at all visible in the Jigsaw and Key Caps icons. This suggests the other gridding could be a dither/shading/rendering choice on lightly colored areas, could this be so? If you experiment with the number of colors, desktop pattern and the rendering themes, does the gridding vanish for some choices? Do you see any gridding when displaying color photos that you have taken, or is it mostly in desktop area renderings?

 

[MacMan]

I had a similar thing on PowerBook 160 screen before and re-seating the display daughterboard and display ribbon cables solved it. Possibly doing the same on your machine might do the trick, just beware that the display cables can tear easily.

 

[Metalchic]

aha, i've seen this before. its a possible symptom of multiple problems.

there are multiple layers and parts that make up a TFT screen, if you've ever taken one apart you would know. the layers are like this

outer protective plastic coat

main screen (where everyhitng is actualy drawn, best if its madeof glass)

prismatic plastic sheeting (distorts the light coming from the light source)

transprismatic plastic sheeting (distorts the light)

thick prismatic plastic plate (added thickness and strenth)

Back plate (this is a plastic metal combonation support plate that binds all the pieces together and houses the Cold Cathode Tube used as the light source in most TFT screens from the era of the PB100 all the way up through the 1400 and 3400 computers, it is even used in Windows/Dos based computers of the time.)

a number of differnt common LCD probelms are usualy linked to specific parts of the LCD. the specific problem you are reporting is usualy a sign of either poor manufactureing or an ageing polarization effect. as i'm sure everyone is aware of somthing to dread of any LCD is polarization, where UV light energizes and then melts the crystals into a permenent 'on' position blanking the screen permenently. over time this can happen even under normal conditions. super long periods of use for poorly manufactured or flawed screens causes the hardenenign of the crystals making it look like the gap between the pixels is increaseing. this is irreverseable. replacement is the only fix.

another problem that it could be would be missalined prismatic plastic sheets. these shees used to distort and evenly distribute the light form the Cold Cathode Tube. when this happens it causes the light to apear in such a way to exsensuate the areas between the pixels. if you turn the backlight off and shine a bright light onto the screen so you can see the screen without the backlight and you dont see them this is the case. other things related to this layer is if you see large black areas (like a black rectangle drawn on the screen by a program) and it looks like theres tiny multicolored confetti on the screen you cant get rid of. its a coleltion of dust particles between the prismatic layers. cleaning by a skilled tech is required to fix this. it is unpreventable.

i hope this is been helpfull, it coes from my 6 years of excperence4 researching and takeing apart laptop screens.

 

[tomlee59]

a number of differnt common LCD probelms are usualy linked to specific parts of the LCD. the specific problem you are reporting is usualy a sign of either poor manufactureing or an ageing polarization effect. as i'm sure everyone is aware of somthing to dread of any LCD is polarization, where UV light energizes and then melts the crystals into a permenent 'on' position blanking the screen permenently.

In LCD parlance, "polarization" has a very special meaning. Rather than something to dread, polarization is in fact the very basis for LCD operation. You are actually referring to the phenomenon of a cooked display. Such cooking is exceptionally rare in a standard laptop display (it is only somewhat common in projectors), and in any case will not result in the perfectly regular pattern described in the original post.

another problem that it could be would be missalined prismatic plastic sheets. these shees used to distort and evenly distribute the light form the Cold Cathode Tube. when this happens it causes the light to apear in such a way to exsensuate the areas between the pixels. if you turn the backlight off and shine a bright light onto the screen so you can see the screen without the backlight and you dont see them this is the case. other things related to this layer is if you see large black areas (like a black rectangle drawn on the screen by a program) and it looks like theres tiny multicolored confetti on the screen you cant get rid of. its a coleltion of dust particles between the prismatic layers. cleaning by a skilled tech is required to fix this. it is unpreventable.

Again, you are describing a mechanism that will not produce the perfectly regular grid pattern described in the original post. Of the various hypotheses offered in this thread, Wally's recent supposition about a desktop pattern/display setting issue seems the least improbable.