Stuck column of pixels

[mDust]

I did try jscreenfix but it didn't help. Thanks.

Thanks for the info on the LCD pixels. I knew some of that but never connected the dots there. It makes perfect sense now.

I've decided I'm not going to try to get it fixed. I'm dealing with it, and it's not even that big of a distraction considering I use this thing for web browsing only.

If someone reads this that knows a way to somehow reset the entire display, though, I'm all ears.

[Konrad]

soc's info is accurate.

Most modern LCD panels use active-matrix thin-film transistors (active-matrix, TFT displays, TFT technology). Each pixel displayed on the LCD is actually composed of three subpixel transistors which collectively compose RGB.

So-called "dead pixels" are the result of any of the RGB elements failing, permanently being stuck in an on, off, or fixed intermediate state. Most people expect dead pixels to be black but they can just as easily be white, the vast majority of dead pixels actually have only one failed RGB component (nearly invisible on most still images, hardly noticeable on moving video without careful scrutiny).

You describe what is effectively an entire line of dead pixels, the blue component is permanently on at some intensity. To me this suggests that one of the signal lines (the one which controls blue vertical #768 on your display grid) is not working; it is affecting whichever gate on all those blue transistors turns them on, at least partially.

Display controller chips usually use sophisticate timing and multiplexing signalling methods to get mexapixels out of only a few dozen I/O pins. If your problem was being caused by some kind of chip failure then it would have a much more prominent (and geometrically bizarre) impact on your display. It is possible that your LCD module contains a number of discrete chips which each process a limited area on the screen and one of these has suffered a minor failure - I doubt it very much because a large number of discrete logic parts would cost much much more and well ... it's an Asus Eee.

Perhaps your LCD has been bumped or damaged, disconnecting or misaligning this signal lead where it connects (to the glass) at one of the edges or corners. This connection can be very tiny (an electrical contact strip, 3 or 4 connections = width of 1 pixel), requiring magnification to spot. It might even be hidden inside the LCD subassembly (usually a million screws and a protective sheet of reflective mylar which can be safely removed from the back of the display, but the components inside are very fragile; do not touch/adjust any trimmers or inductors within the LCD module).

If you're lucky, then one very tiny connection has somehow worked loose and is grounding against the chassis interior or touching something metal like the back of a capacitor where it shouldn't - a comparatively easy thing to spot and fix. Alternately, a tiny piece of debris has somehow worked into the contact strip, shorting or preventing a single electrical contact. You can affect these contacts by running your fingers along this (possibly sharp) edge, possibly working them back into the places they should be.

Alas, far more likely, one of the wires on a connector ribbon has broken. This can be a bitch both to detect and to repair. I would suspect fatigue points near the connector ends and in the area where the ribbon bends every time the laptop is opened and closed. Brilliant manufacturers sometimes place things like Flexible Electrical Wiring immediately adjacent to things like Sharp Metal Edges. These faults can be difficult to detect visually because the wires are very small, you'd probably need to check continuity (on every single lead) with a meter even though you already know all but one (or at worst, two) of them work properly. It's always possible that an end connector is loose, but it seems unlikely because that would have more serious effects on the display. I don't know what your experience with dismantling consumer electronics is, but I *highly recommend* using extreme caution when moving or separating PCBs because they can be connected by any number of these little multi-wire ribbons, and if these ribbons are not properly disconnected (usually a little locking latch/bar) they will sometimes tear apart quite easily and you will cry.

Replacement LCDs can be purchased but often cost half as much as the whole laptop (part numbers are always found on the back). Replacement ribbons, connectors, and such might be available for purchase from the OEM or from companies like Foxconn or Sager or from laptop repair people, they are usually model-specific but cost pennies (if available) but more often have to be "constructed" (because they aren't). You're a modder so "constructed" can be whatever you like, but I've had success in the past just using the dead ribbon (it's still got 999/1000 good connectors) and one length of 30 gauge or smaller wire strung from end to end ... I'll confess that my attempts to perform surgical soldering on these ribbons have, um, lost a few patients.

If you checkout all of your ribbons and connectors and the problem remains uncorrected then you might be able to test a panel from another laptop. (Laptop displays, like television tube displays, are almost all built using a handful of standardized form factors; of course there's always a few that aren't.)

I've repaired and refurbed many PDAs and phones (back when they were still worth servicing) and seen and corrected this particular screen problem a few times, usually caused by the unit being dropped or thrown or sat upon. I expect laptops are fundamentally the same thing, just bigger (in fact easier to service because laptop screens don't use touch grids).

jscreenfix is a software solution ... it might be able to visually minimize or compensate for the problem to some extent but will not actually correct faulty hardware.

[mDust]

You're the man Konrad!

Perhaps your LCD has been bumped or damaged, disconnecting or misaligning this signal lead where it connects (to the glass) at one of the edges or corners. This connection can be very tiny (an electrical contact strip, 3 or 4 connections = width of 1 pixel), requiring magnification to spot. It might even be hidden inside the LCD subassembly (usually a million screws and a protective sheet of reflective mylar which can be safely removed from the back of the display, but the components inside are very fragile; do not touch/adjust any trimmers or inductors within the LCD module).

I don't think I'm going to open this thing up unless it gets much worse. The risk outweighs the chances of success right now.

I don't know what your experience with dismantling consumer electronics is, but I *highly recommend* using extreme caution when moving or separating PCBs because they can be connected by any number of these little multi-wire ribbons, and if these ribbons are not properly disconnected (usually a little locking latch/bar) they will sometimes tear apart quite easily and you will cry.

My experience with dismantling them this pretty high, but my experience with fixing them isn't. I've successfully fixed a TV, DVD player, and a PSU. The only thing I've ever killed by accident was a fubar iPod. The screen cracked.

I'll confess that my attempts to perform surgical soldering on these ribbons have, um, lost a few patients.

I'm a novice solderer so this isn't even something I'd consider trying without tons of practice first. I can handle normal sized components, but when things start getting smaller and more compact, things start to happen. I can't even imagine trying to solder at the pixel scale...

jscreenfix is a software solution ... it might be able to visually minimize or compensate for the problem to some extent but will not actually correct faulty hardware.

Yeah, I honestly didn't expect it to work, but I figured it was an easier and safer attempt compared to cracking it open and sticking my clumsy fingers near LCD components.

Thanks for all the info! If the problem worsens I'll refer back to this before I start pulling screws.

[Konrad]

I'm a novice solderer so this isn't even something I'd consider trying without tons of practice first. I can handle normal sized components, but when things start getting smaller and more compact, things start to happen. I can't even imagine trying to solder at the pixel scale...

Just practice hand-soldering 0.8mm and 0.75mm pitch FBGA parts, draw-soldering 32-pin SOICs, and 0804/0603 SMT parts. When you're prepared to go smaller then you've got about 50-50 odds on one of these cables (no joke).

[mDust]

Just practice hand-soldering 0.8mm and 0.75mm pitch FBGA parts, draw-soldering 32-pin SOICs, and 0804/0603 SMT parts. When you're prepared to go smaller then you've got about 50-50 odds on one of these cables (no joke).

Haha...in that case I think I'll pass. I might still practice small-scale soldering though.