Finished the Quadra 950 ATX converted power supply. As I mentioned before, it's using a Corsair HX1200 which is a PSU from 2016-2020 that is no longer sold but you can find them used and in good condition. It has independent regulation of the voltage rails, and provides 30A on 5V. It's an oversized PSU but works fine in the large PSU enclosure the Quadra 950 uses.
For now, I'm using the standard harness board that the PSU has (ie. I am not hard soldering the wires to the PSU PCB itself). If I find that there's too much loss or if it becomes a problem later, I will change it. But I'm getting a strong 12V, -12V, and 5V at the logic board so I think it will be ok. I have two peripheral cables (4pin molex) also going out the original holes for those cables, but note that I opted not to go all out and reuse the original connectors. The lower left corner of the picture has the original harvested relay from the stock PSU that will drive the passthrough power port (for monitors, etc). It is driven by 12V and will provide passthrough power only once the PSU has turned on. Works great. The Corsair PSU is held on by new stand offs I put in place. I drilled four holes and mounted the stand offs and then mounted the PSU to it.
For the PS ON signal, I'm doing the usual transistor based inverter solution.
There was some rust on the original metal PSU enclosure. Evaporust got it all off. There was some pitting of the metal but it's ok.
I put new zip ties on for the grab handles. The original zip ties Apple used had gone brittle and were crumbling so I replaced them. There's a 120mm Noctua fan installed. Yes, it might not provide as much air flow as the stock fan, but it's still pretty strong. I have the old fan in case I need it but appreciate the lower volume of the Noctua.
Here's the other side of the reassembled PSU with the cables.
PSU works great!
I just need to figure why I'm getting a loud pop from the speaker before the chime plays each time I cold start the Quadra. I printed out the schematics
@Bolle generated for his Quadra 950 reloaded project on github. Looking at the speaker area now to see if any of the blocking or decoupling caps have gone bad. They are ceramic SMD caps. Pulling them off one by one to check them.
I believe @Bolle mentioned the units he had were doing the same thing so there must be something that goes bad on these units over time maybe? Another thing for the to do list.
