power supply problem

[Kenneth Martinez]

> Replace the 7912 with new one. Also check those 15uF caps (I guess they
> are tantals wich are prone to failure). I'd replace all elcos in PSU
> (hey how old they are? - they go dry over the years)...

how long do they usually last?  this synth's about 15 years old and all the
parts look to be original


> ... add some 10-100n ceramic caps...

ok, I'll "refurbish" this PSU by replacing & adding parts as you
suggest...local stores don't stock the 7912 so this'll have to wait while I
order the parts :-(


Also...I'm curious - what's the benefit of this "switching" type of power
supply versus just having the first transformer with all the needed
secondary windings?  Does it just replace the 60 Hz ripple with a 30kHz
ripple (or whatever frequency it switches at)?  The voltage regulators
still have heat sinks on them, so what's the advantage?