4 Feb
2011
4 Feb
'11
11:30 a.m.
Also, the machines are generally designed to avoid
hurting themselves.
The big higher end stuff tends to have enough protection circuitry
that power supply (and environmental) failures do not end up
destroying the rest of the electronics.
My view is that protective devices, whether to protect the machine or a
person, are there to do their job if there is an unforseen failure. They
are not there to protect against probably known problems.
In other words, of coruse I fi a mains fuse of the correct rating in
every machine I run. It will hopefully protect the rest of the machine,
and maybe prevent a fire if there's a mahor PSU failure. But if I know I
have PSU problems, I don;t rely on that fuse alone. I will use a series
light bulb to limit the current.
I wil lhappily use an RCD t protect against me touching a live part when
working o nthe machine. But this doesn't mean I will be careless and work
on the machine while still plguged in.
IBM mainframe and midrange equipment has an unbelievable amount of
extra stuff in the power supplies. I do not worry much at all about
turning on some old bit of IBM gear - if there is a problem, the
It's your machine, you can do what you like. But I won't go along with it.
machine will give a power check (or temperature
check), shut down
safely, and will let me know to pull out the Big Blue Binder with the
repair instructions.
Which if it's anything like any other IBM 'service' manual I've seen,
it'll tell you to rpelace FRU <foo? and won't actually help you to find
the problem.
-tony