PSU or Motherboard Failure?

Hi Everyone,

Yesterday, my PSU went bang with a spark, machine went off and the circuit breaker in my house tripped. The PC is a new build, a month old, so I've had some daily use out if it.

I took the PSU out of the machine and tested it with a paperclip bridge between pins and a case fan attached, no response so I think it's dead.

I've ordered a new PSU, but I want to make sure it's definately the PSU causing the issue before I risk blowing another PSU. Is there a way to make sure it's not the motherboard or a motherboard mounted component causing the issue?

Background: PSU was Corsair TX550M, Motherboard is MSI X470, Case is Corsair Carbide 100R. To be completely sure, I thoroughly checked the hardware setup when I disassembled it to diagnose. Motherboard risers screwed in well, no breaks in any cables, no noticeable issues.

Any help would be gratefully received!

Thank you
James