[sdiy] Korg DW-8000 power supply help?

[Scott Nordlund]

> > That sure is a curious observation. I'd look really hard, or put a lot of hours on the unit before I'd trust that
> > your repair is solid...
>
>
It was weird to me, too. I figure I'll let it bake for 3 or 4 days
solid, and if everything's still working I figure it's probably safe to
let go.



Dunno how much you've tested it so far, but I'd expect it to go bad
again when it's cold.  I've noticed before that leaky electrolytic caps
can improve as they heat up.  I recently fixed a Kurzweil K2VX (these
are fairly notorious for inadequate capacitors in the PSU), I could
switch it on while watching the front panel and monitoring the +5v rail
on a scope: It started off crashed with nothing on the display and
large spikes on the power supply.  Slowly it would smooth out, the
front panel LEDs would start to flash as it would repeatedly reset and
crash again.  After a few minutes the spikes would disappear entirely
and it would boot up as normal.  This isn't the same as reforming the
oxide layer.  I think the cap had vented and lost a lot of electrolyte,
in the process greatly reducing its performance and increasing leakage
current.  The next time I'd switch it on after letting it cool down, it
would crash again.  It's possible that you have a part that's doing the
same.  And if it's drawing enough current to pull the power down that
much, it's likely getting very warm, so it shouldn't be hard to find.