PM G5 (late 2005) boot/wake problem

gsteemso

6502
I alluded to this issue already in a thread about using large displays with this class of machine, but the problem has expanded enough to justify its own thread.

The symptoms: If the machine is booted with a maximum-sized display attached to the GeForce 6600 (the regular one, not the low-end LE version), or – now – if it is woken after sleep regardless of monitor configuration, it does not provide a video signal; if the KVM is switched away and then back it fails to register that it has had its peripherals returned; and after about a minute of apparently being frozen, the fans all kick up to maximum velocity, with no further changes if you then wait longer. The only way I can recover it from this state is to hold down the power button until it forces the power off.

When the machine does boot, it will only show a full-size picture (on monitor port 2 of the video card) if monitor port 1 of the video card is already displaying a picture. Running it single-headed at maximum resolution is simply not possible, though if you have a monitor with two inputs, you can run both heads to the same monitor and simply switch to the higher-resolution signal after successfully booting with the other one.

I can find no mention of these issues anywhere online, and the “won’t boot to a maximum-resolution picture” issue stayed the same when I had to replace the video card (the replacement was with the same model). I feel the video card must be close to the root of the problem, though, because the “won’t wake from sleep” thing is a new development since the replacement.
 
Try the basics, you've got the small CUDA/SMU reset switch on the motherboard, also replace CR2032 battery, reset PRAM and NVRAM (via Open Firmware). There is also the Apple Hardware Test CD to diagnose and test things in further detail. I'd also remove the KVM during this time as they are well known to cause issues.
 
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