5150 PSU blowing fuses

[VERAULT]

So I have a 5150 PSU that was from a working system (completely working fine) I was using it to test a sketchy 5150 motherboard. Immediately upon powering up the 2a slow blo fuse blew. Removed psu, installed new fuse and attempted to turn it on with nothing connected whatsoever. IT now keeps blowing the 2a fuse (there is a 4a slo fuse that is fine next to it)

Any ideas what to check as it blows the fuse immediately?

 

[Agent Orange]

So I have a 5150 PSU that was from a working system (completely working fine) I was using it to test a sketchy 5150 motherboard. Immediately upon powering up the 2a slow blo fuse blew. Removed psu, installed new fuse and attempted to turn it on with nothing connected whatsoever. IT now keeps blowing the 2a fuse (there is a 4a slo fuse that is fine next to it)

Any ideas what to check as it blows the fuse immediately?

Obviously a short. You can Google for a schematic. The first thing that I would look at is the bridge rectifier circuit as well as any caps that appear popped.

While not specifically your particular PS, the following will provide a fairly good example of where to look:

https://en.wikipedia.org/wiki/Power_supply_unit_(computer)