Re: System Saver IIgs -- ID of burned part?

[w_tom <w_tom1@usa.net>]

  Ineffective surge protection is defined by any of four critical
characteristics: 1) too close to transistors, 2) too far from earth ground, 3)
too expensive to protect only one appliance, and 4) too undersized for effective
surge protection.  Any surge protector that is only good for one surge is not
just undersized; it is probably grossly undersized - ineffective surge
protection.

  Three MOVs in the Apple II are how surge protection was once installed in all
appliances of and before that period.  Those $0.05 and $0.30 components are no
longer installed because, in electronic appliances, they violate critical
characteristics one,  two, and four.   Plug-in surge protection, such as the
power strip, usually violates all four critical characteristics.

  Effective surge protection is properly sized so as to shunt a surge to earth
ground AND remain operational for the next surge.  Joules is a benchmark of
surge protector life expectancy.  However derate the speced joules for a plug-in
surge protector to as little as 1/3rd.  IOW a plug-in surge protector rated only
at 345 joule may actually be 115 joules and never more than 230 joules in surge
protection.  Just another reason why plug-in surge protectors violate critical
characteristic four.

  Effective surge protection protects everything in the building for about $1
per protected appliance.  If V1, V2, and V3 are MOVs (such as the V130LA10),
don't worry about them.  If for no other reason, they are too far from earth
ground to be considered grounded.    Instead install effective surge protection
connected less than 10 feet to central earth ground.  That less than $50 'whole
house' surge protector will effectively protect the Apple II and other
electronic appliances - typically for more than 10 years..

Tom Zuchowski wrote:

> FWIW, MOV surge protectors are like crash helmets, they are good for one (1)
> use and then you have to replace them.
>
> MOV's are also subject to "wear and tear". Every time they stop a surge,
> they lose some effectiveness, until the day comes when they fry like yours.
> People who are serious about surge protection will replace all of their
> MOV's once per year or thereabouts.