[net.micro.mac] Power Supply: What Part Fails?

jer@peora.UUCP (J. Eric Roskos) (07/02/85)

Recently we've seen a lot of discussion that suggests that the Macintosh
power supplies may fail at a somewhat higher-than-anticipated rate.

However, one thing I haven't seen discussed is the question of what part
fails?  I recall that one person early in the discussion identified some
part that broke down and shorted the flyback transformer... is this the
part that is failing?

Are there any recommended substitute parts for still-working power supplies
that can be used to avoid this problem?  Since my Macintosh has been out
of warranty for many months now, naturally I would like to avoid having it
fail, if possible.

Also... in early discussions of the machine in magazines like Byte, I
recall reading that George Crow designed a switching power supply for the
Mac, which didn't make it into the early versions of the machine -- a non-
switching power supply allegedly had to be used instead.  Is it this non-
switching power supply that fails, or the switching power supply?  How
can you tell the two apart easily?
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