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View Full Version : Powerbook LCD "shift and shrink"


mischief
Nov 12, 2003, 01:36 PM
Let me start by saying that I have more skill inside the case and training in take-appart than 99.99% of users due to AppleCare training. What I'm about to describe is a side effect of a side job I did for a friend with parts of unknown origin and I strongly discourage ANYONE from attempting this operation without training and an appropriately equipped lab.

Last night I replaced the screen on a second generation (667Mhz without DVI) TiBook. This was a hellish experience that I will never voluntarilly repeat.

After re-assembling the machine, zapping the PRAM and laying a curse on Jonothan Ives The machine rebooted and successfully cycled the screen..... sort of.

It goes like this:

Chime

2-3 seconds of odd, tiled patterning

Jaguar Startup spinny, centered and normal

Login screen, also centered and normal.

(This is where it gets odd)

Upon Login the screen "shifts" to the following:

Screen image is compressed into 3/4 it's usual area, pinned at the upper left.

Top Inch of image is echoed at bottom inch of screen with a two-pixel width gap between bottom of active screen area (Dock emergent edge) and the echo below it.

Right edge of active screen area is roughly 1" from edge of LCD panel, last half-inch of visible desktop at right is "stretched", as if the whole 1/2" strip was getting the data for only three to five pixel columns.

This is maddening.

I've seen similar issues on other LCD's and I can't remember for the life of me what the solution was !!

There are, of course, no monitor calibration tools in either the system, the AppleCare CD kit or the Open Firmware CDs ( Other than colour :rolleyes:)

Ideas?

Rower_CPU
Nov 12, 2003, 01:49 PM
The image shifting on login implies it's a resolution issue. I assume you tried other resolutions to see what happens?

mischief
Nov 12, 2003, 02:06 PM
Originally posted by Rower_CPU
The image shifting on login implies it's a resolution issue. I assume you tried other resolutions to see what happens?

That was my first step.

I then proceded to use every calibration app I could find, both within the system and in my more arcane CD collection. It seems that nobody has ever thought about needing to reposition the image on an LCD. I'll be checking VT later for a freeware utility.

It's frustrating in that both the OS 9 subsystem, when booted from a CD and the Darwin subsystem seem to see the whole screen... just not a fully logged OS. Grrr...:mad: :p :(

Rower_CPU
Nov 12, 2003, 02:30 PM
Yeah, it's definitely an odd one.

Since you mention that the part is of questionable origin, is there a possibility it's not up to par?

cr2sh
Nov 12, 2003, 02:37 PM
Originally posted by mischief
That was my first step.

And what happened when you tried other resolutions? Does the image remain the same size, location, with the same echo?

mischief
Nov 12, 2003, 03:02 PM
The screen assembly was the entire screen/lid assembly with wire harnesses and hinge mounts.

It seems to have been a genuine Apple part though there were some very slight cosmetic differences in the wiring, implying different revisions.

Though, to my knowledge the screen assemblies and resolutions for the various TiBooks before AGP video was added should all be the same. Perhaps not.

The wiring harness on the old assembly had primarilly red wires running from the raw LCD connector, wheras the new one had predominantly blue wires. Other than that, the screen assemblies appeared identical.

Cr2sh:

Good question. Yes, the echo and offset remain identical. I seem to recall that when I saw this last I was using a brand new video card in a brand new G4 desktop with a Sony LCD. It turned out to be an issue of updating the video card's firmware..... too bad I can't find a similar firmware update for the PB G4.

cr2sh
Nov 12, 2003, 03:27 PM
Well, without knowing more about the replacement screen I would guess, that the resolution of your new screen is 1280x854, while the (Gigabit Ethernet Powerbook) 667 screen originally had a native of 1152x768.. the video card (ATI Radeon Mobility 4x AGP?), or firmware.. or whatever... for that model has got you.

I can offer you no suggestion but re-replace the screen with one of native 1152x768 resolution. :) Sorry I can't be more help, let us know how it works out!

mischief
Nov 12, 2003, 11:48 PM
I believe I have found th culprit.

The screen I installed was bought off e-Bay and came off a dead-CPU 1Ghz TiBook. This would mean that the screen is, indeed a higher-res model than the original.

Kudos to cr2sh for guessing correctly.;)

Unfortunately, this means that my client is SOL for a while.:rolleyes: