17 Feb
2004
17 Feb
'04
12:19 p.m.
Tom> Big, huge, gargantuan, monster arrays of
dipped silver mica
Tom> caps? Seriously, I think you just have to change them often,
Tom> eg. decadely.
Actually, at least in switching power supplies, ceramic capacitors are
now a good option. You can get ceramics of several hundred
microfarad, and they are quite small. More expensive than tantalum, I
expect, but more reliable. And if they do fail, they normally fail
open, not shorted as electrolytics do.
Not only that, will be found shorted, even leaking like a resistor.
Seen these happen with ceramics. When they leak or intermittently
shorting gets you chasing all over. But many times I stop and stare
at schematics and think, try a area where a component is most likely
is failing. Also even a service mode that lets me disable or adjust
a item was helpful. This usually nails it.
Even a semiconductor stuff is known to leak or make signals
intermittent or constantly jumpy (volts) or jitters (waveforms).
Optical coolants (same stuff as anti-freeze) soaked resistors
(especially flameproof & fusible resistors) resistance went down and
blow the semiconductor IC eg: vertical IC after awhile. Made repair
more diffcult till I found out why.
Cheers,
Wizard (working on TV, projector & monitor for shop).
paul