[G4] Exploding Power supplies

[Ron Steinke]

On 22 Sep, 2005, at 15:10, Kevin Willis wrote:

I picked up a pair of B&W G3's over the weekend. I plugged one of them 
in and heard a pop and saw sparks shoot out of the power supply.  So, I 
tried the other one.  It worked fine.  I installed OS X and got it up 
and running with no problems.  Until today.  I flipped on the power 
strip that it is plugged in to and it blew up like the first one.  Is 
this a known issue with these machines?  I haven't had any trouble with 
my G4, and this is my first experience with the B&W's.  Any help would 
be greatly appreciated.

Just out of curiosity, what voltage setting did your B&Ws have? There 
is a switch on the rear panel of the box that lets you select the 
voltage between american (115V) and european (220V).

I have restored many B&Ws without ever seeing what you describe. Once, 
I did see an Apple Studio Display 17" do the "spark and arc" act when I 
plugged it in. That was interesting but not desireable.

The most common problem I have seen is "impact damage" to the B&W front 
panel where the power button is located. Many of the machines that come 
to me have been used in a school setting and small kids often swing 
their feet when sitting at the table. Scuff marks on the front near the 
power button can mean that the power button mountings have been knocked 
out of place and are causing the button to stick in the depressed 
position. That's one of the first things I look for.

Other than that, I haven't heard of frequent power supply problems 
especially where there are sparks shooting out of the box. Of course, 
every part has a point of failure because of the materials used to 
build it. It is possible that you were the person on the scene when 
that point was reached and it was just a coincidence that you had two 
power supply failures so quickly. On that note, I have had floppy 
drives fail with amazing frequency.

Sorry that I can't point you in any specific direction to assist except 
suggest trying a third power supply.