[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Apple IIe - Boot problem and unusual notes
myoldmac.net wrote:
If it is the capacitor that I have indicated, then its fairly simply
to find a replacement. I managed to pick them up at the local
electronics dealer here in Australia (Jaycar). It was a little fiddly
wiring in the new capacitors, but nothing terribly difficult.
Great Info ! thank you. I will open tha PSU and have a look.
Funny wise the PSU works, despite the fact that it burned a little
bit :-)
That is a characteristic of a popped line bypass capacitor
that doesn't blow the fuse.
But I think it is better to replace the capacitor
(and I thougth this problem exists only on Mac Boards...)
It is good to replace it, if only because leaving the shorted
(and blown open) capacitor in-circuit increases the risk of
further damage.
This problem is common to virtually all power supplies--and
to power strips with line bypasses as well. The good news
is that the more common ceramic capacitors seldom fail in
this way if properly rated and surge-protected.
The design purpose of line bypass capacitors is to attenuate
high frequency signals or pulses passing between the AC line
and the power supply. In the case of switching supplies, the
important direction is from the power supply to the line.
The bypass capacitor(s) reduce the levels of switching transients
coupled to the line to reduce interference generated by the
power supply.
If you use an EMI-filtered power strip, the line bypass capacitors
in the power supply are redundant (except for radiation from the
power cord), since the power strip provides a line filter as well.
-michael
NadaPong: Network game demo for Apple II computers!
Home page: http://members.aol.com/MJMahon/
"The wastebasket is our most important design
tool--and it's seriously underused."