27 Jul
2011
27 Jul
'11
1:34 p.m.
Actually SMPSUs are quite simple, especially from this
vintage. The
trickier parts are the voltage overload and voltage good detection
circuits in my experience. I'm sure others here will come back with good
advice on what to check but working your way methodically through the
stages of the PSU isn't that hard - just be careful and remember to
allow those large caps to fully discharge before touching anything!
The BA11-K supply is benign in this respect. It uses a convenitonal
iron-cored mains transformer to drop the incoming mains voltage to
20-30Vac. This is then fed to the regulator 'bricks'. While these
contain some large capactiors [1] storing enough energy to blow
transistors apart, the voltage is not high enouhg to give you a lethal
shock.
[1] A friend of mine (not on the list) refers to them as a 'CFE',
standing for 'Capacitor, F***ing Enormous'.
-tony