Powerspec G436 Power Supply replacement issue


Hi folks!

I'm having an interesting PSU issue. I bought a new Corsair HX1200 to upgrade my existing PC (with headroom for a GPU upgrade at some point). I've been building my own PCs for like the past 20 years, but due to GPU shortages I bought a premade last year, a Powespect G436, because it came with a 3070. So I install the new PSU and the PC doesn't even turn on. It clicks, one LED on the mobo blinks (the CPU LED), then nothing. So I try all different cables, including the one to the wall and still doesn't work.  I put the original one back in and boom it's fine. Hmm. Then I take a PSU out of one of our other PCs - it's an HX750 - and it also doesn't work. It clicks like the other one and otherwise nothing. I then put the HX1200 in that other PC and it starts up just fine. I'm at a loss. Perhaps it's an incompatible 24pin or 8pin CPU on the mobo?

G436 motherboard and PSU:

  • Mobo - MSI Z490 Plus - apparently not a mainstream retail board but something used in pre-mades
  • PSU - Powerspec 750BSM - semi modular so I can't use the same 24 pin / 8 pin cable

Totally would appreciate any thoughts here. I'm assuming I'm doing something wrong since a lifetime of experience is that's usually the case, but I feel like I've ruled everything out.


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