That said, I
take some care before applying power. In fact turning it on
is one of the last things I do.
Me too.
First I clean out all the dead flies, mice droppings, cobwebs and whatever
else may have accumulated - this usually involves some level of disassembly,
which is required anyway for the next step.
Then I do a detailed visual inspection, paying special attention to
"power" components, looking for discolored capacitors, resistors etc.
I also look for corrosion in sockets/connectors, and anything else that
looks at all out of the ordinary - I spend a fair bit of time at this.
At this point, I also check anything mechanical (fans, for example). At
least I make sure they're not totally seized. I may also run motors off a
bench supply to make sure they're OK (with the motor disconnected from
the driver electronics, of course).
I also do ohmmeter checks for dead shorts on power semiconductors
(especially chopper transistors, horizontal output transistors), etc. And
on large electrolytics.
Then I chceck the safety ground (earth) connection is good and that it'll
pass a reasonable current. And I put a megger between the mains input and
the earth connection to check for any serious breakdown.
[...]
If possible, I disconnect the power-supply and
energize it separately,
measuring voltages. If it's analog, I ramp it up through a variac,
I nearly always find a way to do this....
monitoring the outputs and current draw as it comes up
to operating
voltage.
I put a dummy load (car bulbs, normally) on the main power rails when
doing this.
-tony