How does one determine what is causing white screen?
As Shipped Unit Description:
- Serial Number: W87130ZKVGN
- Type: iMac "Core 2 Duo" 2.16 24-Inch (T7400)
- Intro.: September 6, 2006
- Disc.: August 7, 2007
- Order: MA456LL
- Model: A1200 (EMC 2111)
- Family: Late 2006 - 24"
- ID: iMac6,1
- RAM: 1 GB
- VRAM: 128 MB
- Storage: 250 GB (7200 RPM)
- Optical: 8X DL "SuperDrive"
System boots to the point that it shows a white screen with a cursor that can still be moved (ie. not frozen). Need to determine what needs to be repaired to put the unit back in service? Can't be sure whether it is a board failure or not.
What I've tried
Tried booting off CD and can get access to see choice of boot drives, can see verbose startup, and can see drive contents. Booting of internal drive results in a white screen with a movable cursor no matter what key combinations or cache clearing "tricks" are tried. Disassembled unit and connections appear OK. Have not been able to figure out how to remove "back" to check other side of logic board, but caps on power supply appear fine.
Additional details of things tried
- Hard drive itself seems to be functional, based on checks after booting from CD.
- Makes all the right noises on startup before the apple and spinning gear.
- Holding down option key on startup works ok. Shows the partitions on the hard disk.
- Holding down shift key on startup doesn't work. Goes into white screen and stays there (but shows movable cursor).
- Holding down D key on startup doesn't work. Goes into white screen and stays there (but shows movable cursor).
- Holding down command V (verbose mode) doesn't seem to work.
- Resetting SMC, PRAM, safe mode doesn't work.
- Prior to failure didn't give any indication that video card was failing. I.e. no lines, no break up or distortion of images.