[G4] MDD power issues

[Ronnie Day]

> Simon Stone
>
> my dual 1GHz MDD has been displaying some behavior lately which I suspect is
> power supply related, but maybe someone can confirm, or suggest other
> possible things to look for. I have an Apple Studio Display (adc) and a
> second HP monitor connected and am running OS 10.4.11. Recently, at boot up,
> as soon as both monitors click on my breaker on the power bar is tripped
> shutting down everything. First I tried disconnecting the HP - same thing;
> then the SD and it was ok. I connected the SD while the MDD was on (maybe
> not the best thing to do?) and it worked ok. Today it got worse: the
> computer with nothing connected will try to start breifly when I press the
> power button, and will shut off - if I try again immediately - nothing. If I
> unplug from power and plug again - power button lights up briefly and shuts
> down. What's happening here, is there anything I should try? Thanks.
>

Most likely the power supply or the front panel power switch. But if
it's tripping the breaker on a power strip, I'd guess PS. However,
first thing I'd do is try another surge protector. Something weird may
be going on there, I think. Personally I use UPS/battery back-ups
because they do a much better job of smoothing out power line
irregularities than a straight surge protector.

Regarding your basic problem, the power supplies in the Dual MDDs are
woefully inadequate, IMO, especially if you're running an early Cinema
Display with the ADC connector. In addition to providing power for
everything in the CPU itself, power for the CD comes from the
CPU/power supply. I have one of the Apple display adapters that allows
use of an ADC monitor with a DVI video card. Not only does this let
you run the ADC monitor through a DVI video card, but it provides the
A/C power for the monitor, taking that load off of the computer PSU.
As I mentioned there are know problems with the switch, too. Search
for info on that one.

I'd also suggest running only a boot drive inside the computer. Put
your other drives in external cases, and use a PCI Firewire card if
you're going to attach more that one or two. Loading the G4 with 4
hard drives, a couple of optical drives AND an ADC connected monitor
is simply asking way too much of the relatively small power supply. I
know, been there, done that.

FWIW,
Ron