1. Is it possible for a short in the motherboard, or a bad capacitor, to blow a power supply?
I don't know for definite, but I'd have thought so. Ideally, all that would "blow" would be something replaceable like a fuse, or it'd shut itself down before it could be damaged. Probably depends on the quality of the power supply.
dubsola wrote:2. Is it bad when capacitors bulge at the top?
Yes, it's the magic smoke
trying to escape.
Or more seriously, it's a sign the electrolyte inside has tried to burst out, which is bad. They're usually designed to vent out the top as a safety valve. On a related note:http://en.wikipedia.org/wiki/Capacitor_ ... l_symptoms
dubsola wrote:3. Is it possible to test a new power supply without fitting it?
Yes. All you're doing by "fitting" one is screwing it into a case. Unless you mean: is it possible to test a power supply without powering any PC components with it, in which case:
"Typically the power supply has a protection circuit that prevents it from operating under no-load conditions"
"It is possible to troubleshoot a power supply by placing a dummy load across its power connectors to see if it turns on. If you don’t mind spending a couple dollars, there are pre-built troubleshooting devices you can get down at your local pc repair shop."http://www.pcmemoirs.com/2011/04/18/how ... therboard/
For testing PC components, you'd typically assemble and test on a bench/table, rather than screwing everything into a case where it's harder to access and replace things (if multiple components may have failed, there may be a lot of combinations to try before you work out what's working and what isn't). It also eliminates shorting problems caused by pins on the motherboard touching the case (which can happen if you screw the board in too tightly or without the right screws).
The bit that doesn't make sense is that if the motherboard is visually damaged, why plug a brand new power supply into it... and when that fails, why plug in a second?