Closed [US] Silverstone SFX 450W power supply for repair or parts

I took a chance at a used power supply and this time it didn't work out so well. This is not a fully working PSU so please read for details.

It's a used Silverstone ST45SF-G modular power supply, 80 plus gold rated. The original seller said they didn't have a 24-pin cable to test it with, so weren't sure if it would work or not. When I tried it with my own cable, it seemed to work, but only some of the time.

The PSU comes with the box, manual and SOME of the stock slim cables. The stock 24-pin and SATA power cables are missing so I included the custom ones I used with the PSU. The custom SATA has connectors for two drives right next to each other. The 24-pin is very short so you will need an extension cable if you were to use it in a full build.

This power supply seems to have a problem with delivering power to the motherboard. I've tried it with three different boards. I used to have it running for a few days at a time but it will no longer boot up the computer. I would press the power button and it blinks momentarily and the CPU fan twitches. It may be a problem with the 24-pin cable I used or the PSU itself, but couldn't tell since I don't have the complete official cable set and I will not open up the PSU to figure it out myself. The jump pin trick works, though. It's just too unreliable for me and would rather have someone else take it for repair or parts.

I'm looking to get $30 + shipping for the PSU.