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I have a 12" PowerBook with no HD and a dead screen. I'm trying to determine if the actual LCD is broken or if it is "just" the graphics card, without taking out the screen and transfering it to another computer (which I intend to do if the screen is working). I've tried connecting the computer to an external monitor, but, since there is no HD, nothing happens. The same nothing happens when I connect my working 12" PowerBook to the external monitor.

Is there a secret keyboard combination that tells the laptop to throw some characters onto the screen (from BIOS or something), and to mirror or output to the external monitor?

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Incidentally, can someone please explain what the startup key combination CMD-OPT-A-V "Force an AV monitor to be recognized as one" really does? can it be used in conjunction with CMD-S "OSX: Enter single-user mode (shell-level mode)" ? how? which combo should be pressed first? – Yossi Farjoun Oct 6 '10 at 12:54
Just to clarify: are you saying that the otherwise-working PB will not boot if the external monitor is attached? – Dori Oct 7 '10 at 1:04
@Dori: no, I'm saying that when I connected the functioning PB to an external screen and booted it up, I did not get an interesting output on the screen until I when in manually (after login and such) and changed the resolution setting in the external display configuration panel. This I cannot do without the main display. – Yossi Farjoun Oct 7 '10 at 8:27

No. Just get a small, cheap HD (even just a 20 GB will do fine here), put it in, and boot from a system installation disk as if you were going to install the OS.

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Will that output to the external screen? remember, them main screen isn't working, so I can't change any settings using a mouse, only keyboard actions... – Yossi Farjoun Oct 6 '10 at 12:52
I would think at boot time you would at least see a gray screen or the blue screen later on the external monitor. Either way you need a system disk to boot from and probably a hard drive to get everything going. – Philip Regan Oct 6 '10 at 13:22

You said you don’t have HD, but I assume you have the SuperDrive that used to come with those. Put the Jaguar/Panther/Tiger CD and boot from it, you should get output.

You might also want to try resetting the PMU of the powerbook. Google or Apple Instructions Here.

EDIT: After reading some more about your problem in the comments, it’s clear now that you have

  • Powerbook #1: No HDD, Unknown Screen Status.
  • Powerbook #2 (Pro): Superdrive not working.

If the above is correct, your choices are:

  1. What Phillip said: get a cheap drive that boots any OS (Linux for PPC would do too) and see if your #1 boots with that USB drive and displays text. with this you cover your screen problem.
  2. Transfer the #2 Hard Drive to the #1 Machine and see if it boots from there.
  3. Try booting from #1 Machine that (if I am not mistaken, has a SuperDrive).

Am I missing something?

And to clarify, there’s no Keyboard combination that will output text on a Macintosh PPC other than a verbose mode or similar, but that’s post initialization. There’s no BIOS or anything like that. (That I remember anyway).

Booting from an Install CD has the plus that you can run System Diagnostics if I am not mistaken.

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This is a good idea. The problem is that I don't have a control group for this experiment: my "working" machine has a non-working superdrive. So I don't know what should happen, I don't know if the external screen will come on without me pressing any buttons etc. That's why I was looking for the solution that involves non-graphics mode.... – Yossi Farjoun Oct 6 '10 at 12:51
Wait, the Powerbook 12’’ has a Superdrive, are you saying that that drive doesn’t work or you don’t know if it does? You can always try any PPC Linux version bootable CD, google Linux PPC, there are quite a few ( for example). If the drive is not working, Phillip’s answer is going to be your best choice. There’s no such thing as a “bios” you can enter to “see text” on a PPC Macintosh computer. – Martín Marconcini Oct 6 '10 at 13:18
There are two machines in the story: One has a screen that never turns on, for a still undiagnosed reason, and no hard drive. The other has a non working superdrive. I'm trying to diagnose the screen problem, while useing the second machine as a control... – Yossi Farjoun Oct 6 '10 at 13:26

Given the two PowerBooks as described in the other questions, here's my 2¢:


  • PB1: the PowerBook without the hard drive
  • PB2: the PowerBook without the SuperDrive


  • Connect the external display to PB1
  • Connect PB2 in Target Disk Mode to PB1
  • Boot PB1

If everything works as it should, PB1 should boot and look just like PB2 (as it's booting with PB2's hard drive). At that point, you can run any necessary diagnostics.

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I like this. This is (somewhat) simpler than pulling out the functioning HD from PB2 and putting it in PB1. So, I can set up PB2 so that it connects to external display and boots password-less etc. Once I can get it to show something on the external screen without needing to press a button from boot, I boot it in Target disk mode, connect BP1 to it via firewire and boot PB1 normally. PB1 should boot from firewire and thus do exactly what PB2 did....Right? I'll try it out and let you know what gives. – Yossi Farjoun Oct 7 '10 at 13:30

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