kony wrote:

To verify, you had a load attached? Many power supplies that need an
external load, would do just that, power on only long enough to stir
the fan, then shut off.

Yeah, I had a load attached.

Assuming you did have the optical drive attached, that would indicate
a failure of the power supply. Confirmation would be obtained by
testing it, as w_tom mentioned, taking the voltage readings would be
something I'd advise if you'd had a voltage meter handy. Then again,
I already knew those were junk power supplies, so if spending the
least amount of $ was the goal I'd put the $10 for a voltage meter
towards a better power supply rather than chancing it on that one at
this point. Then again, a multimeter is a handy tool to have, the
more you learn/do/etc, the more likely you'll have another need for
one.

I'm gonna get a multimeter anyway. It's definitely a useful tool to
have around that no hardware geek should be without.

Even if you don't want to repair it, opening it (after unplugged from
AC for a minute or two) will probably reveal what failed... more often
than not there's visual sign of the failed component(s).

I opened it and I wasn't able to see anything indicating a failure.