Author Topic: PowerBook G4 Ti won't shutdown if external display is attached. It just reboots!  (Read 419 times)

Offline markpaterson

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Hi,

I have a PowerBook G4 Ti 667Mhz and Mac OS 9.2.2.

I've attached it to a 1920 x 1080 LCD, connected via DVI to HDMI cable. Ideally I'd love to run in clamshell mode, but I'm having issues with being unable to shut down, so I've resorted to running a dual display which makes life slightly easier. However, issues persist…

1. When I select 'Shutdown', instead of shutting down as normal it simply restarts. But if I unplug the external display, and then shutdown, it shuts down as normal.

2. This is probably related to #1. If the PowerBook is off and I connect the external display, the PowerBook will automatically power up. Why would anybody want this?!

3. I've set the display arrangement in the Monitors control panel, setting the menu bar and startup display to be the external display, but it constantly forgets this after a reboot. Annoying.

Are any of these issues normal or expected?

I tried a PRAM reset, to no avail. Then tonight I installed a totally fresh copy the Mac OS 9.2.2 Universal Installer (2013 MacOS9Lives edition) from https://www.macintoshrepository.org/126-mac-os-9-2-2-universal-installer-2013-macos9lives-edition-w-cpu-5-9-rom-10-2-1-for-unsupported-g4-like-fw800-mdd-emac- in the hope that it would fix things, but the issues remain. These issues also were present when using the model specific version of the OS.
« Last Edit: May 10, 2022, 08:17:40 AM by markpaterson »

Offline GaryN

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I think you're looking for answers in the wrong place.

1. When I select 'Shutdown', instead of shutting down as normal it simply restarts. But if I unplug the external display, and then shutdown, it shuts down as normal.

2. This is probably related to #1. If the PowerBook is off and I connect the external display, the PowerBook will automatically power up. Why would anybody want this?!

The #1 suspect here is the DVI > HDMI adapter. HDMI and DVI have a "hot plug detect" pin. This is supposed to trigger a data interaction between the host and display to determine and set the correct resolution if and when a different monitor is plugged in. In 2002 however, this was better called a "hot mess" pin. The PB is turning on simply because there is a voltage on that pin.

Theoretically, you should be able to:

1) Power OFF the display first, then shut down the PB and it should stay off. Also theoretically, powering the monitor back ON next time should also start the PB.
2) Eliminating the hot plug signal MAY resolve the issue and allow the PB and monitor to operate "normally".*
    * It's also possible it may prevent the PB from "finding" the correct rez on startup, but still worth a try at least.

You accomplish #2 with some very thin (maybe masking) tape, a razor blade, tweezers and a steady hand. The objective is to tape over the #19 pin on the HDMI connector (probably on the monitor plug side) to prevent contact. You cut a strip just wide enough to cover that one connection. A magnifier may be helpful unless you have great vision. Fortunately, that pin is on the end which makes it a LOT easier than if it was in the middle somewhere.  8)

Offline markpaterson

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Wow what a pain, but thanks so much, this is great info. I'll give that a shot!

 


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