Could the lab down the road test your PSU for you ? That
is a tougher thing to do, because a proper test required
a programmable load box, if you want to do the job right
(i.e. test at rated load).
If you cannot borrow any more of that lab's time, you
can start a PSU by itself, by connecting PS_ON# to
one of the COM pins (there are COM pins very near to
PS_ON#). The PSU fan should start to spin, in response.
All that this test tells you, is that the control circuit
still has some response in it.
I do not recommend opening up the power supply under any
circumstances. The two main electrolytic caps store an
unbelievable number of joules of energy, and are not to
be trifled with. Even though the caps likely have bleeder
resistors across them, bleeders can open up, and putting
shunts across caps like this could deafen you (think
fire cracker loud). As a result, there is really no point
of opening up the lid of the supply. Using your nose
is as good an indicator of health as any, and if you smell
something burnt in the supply, you have all the info you
need about your supply.
I test my PSUs here before I put them in a computer. I
have some power resistors I got from an electronics
store, plus some Minifit Jr pins to connect to the
power supply connector. I actually load all five rails
on the power supply. What I cannot do with this setup,
is draw full rated load from the power supply - instead
I draw only about 1 amp or so from the major outputs, and
maybe 0.5 amps from the others. That way, the resistors
do not get too warm (I still have a fan blowing on them).
Getting decent dummy load resistors means too much bulky
stuff to store, when I'm not using the tester. It is possible
to design "electronic loads", using power transistors and
the like, but you still need to fabricate a cooling solution.
(No matter how you build a load, the heat has to go
somewhere.)
I suppose $200 worth of water cooling stuff could cool it.
In any case, for my purposes, there isn't enough benefit
for the amount of effort required.
One thing to remember about your old motherboard, and your
new motherboard, is they likely present entirely different
levels of electrical loading to the PSU. It could be that
the PSU is weak enough, that it just cannot handle the new
board. For example, some people have a supply "tip over"
when they add something innocuous, like a CD drive. PSUs
these days, no matter what brand, are marginal at best.
Many of them cannot run at full rated load - some of
the ones with 400 or 450W written on the side, are just
last year's 350W with a new label pasted on it. Picking
good supplies is a tough job.
If you are short of money, the only alternative I can
see, is to buy a super-cheap supply. There was a web site
a while back, where the author weighed ATX power supplies,
and evaluated what was inside. He found that quality was
directly proportional to weight, so if you are at a large
computer supply place, compare the weight of the supplies
and take the heaviest of the cheap ones. (Fortunately, the
Chinese don't think we select supplies by weight, as
otherwise they would add lead plates to the case
)
That is about as scientific a selection algorithm as I
can give you, for the Deere, Powmax, Allied, etc supplies
of the world.
To work out what size supply you need, try this site:
http://takaman.jp/D/?english
Good luck,
Paul
