Is there a chance that a faulty system(cpu,mb,ram) could damage a
working PS?
With a properly designed power supply, no it should not
happen. With a poor PSU it may, due to lack of
safety/shutdown circuitry. What make and model was your
PSU?
A friend has complained to me that his PC had shut down abruptly and he
couldn't power it on, so I went over there to have a looksee.
First thing to do is unplug from AC for several minutes.
From here you can take two paths- if system is rather
valuable, pull the PSU for external testing so as to not
jeopardize the system any further. If invaluable, try to
turn system on again, preferribly having a multimeter hooked
up to the power leads to assess the voltages.
While the system was open it is good to do the usual
examination of cards, cables, connectors, and capacitors. A
failing capacitor realated shorting is not uncommon, or a
cascaded failure.
When I
switched it on, the LED on his mb was shining, but no fans were
spinning, so I replaced his power supply with mine.
If only focusing on two main components, PSU and
motherboard, we have already multiple possible scenarios.
Board was failing and poor PSU got damaged. PSU was failing
and (any) board was damaged. Either part was failing but
the other part was ok.
The other variable is all the other parts connected to the
motherboard and PSU. Thus, being thorough would mean
disconnecting all other parts, having just the motherboard
connected. "IF" that seems to work, and a multimeter
indicates voltages are ok, proceed to add back the CPU,
video (if not integrated video) and 1 memory module, at
which point you hope to get the system to POST by shorting
together the power-on pins on the motherboard with a metal
object. (That is, you had already disconnected the case
front panel connections and USB headers, etc, too.)
The fan on the cpu
started to spin, but still no POST. Then there was trouble: my PS
started to make some noise + some burning smell, so I switched it off.
At that point, since the system had been opened and "things"
done inside, it would be good to reexaming everything before
any further action, to be sure there weren't any cards out
of place, or cables, etc, possibly shorting out. Even then,
as mentioned previously a decent PSU should have turned off
and refused to start until the AC power had been
disconnected for several seconds. If there wasn't any other
extreme (obvious?) problem, it "could" be that your PSU
which died, was almost dead anyway or low enough quality
that it wasn't really suitable for use even though it had
been working (dangerously, a risk to YOUR system before
now).
When I got home I've put back my PS in my box, and then the whole room
started to smell in the way we all know and adore. Hence the question
at the top.
Hopefully only the PSU is gone. We could assume his system
has damaged your psu because your psu lacked the appropriate
design to turn itself off. We can now only hope your psu at
least had enough protection to turn off before damaging your
system.
So yes it seems what you suspect has happened but it is not
always what would happen in same situation (with a better
PSU).
