but since it has a -5v rail

Which equals old low efficiency PSU in range of 70%, i.e. produce a lot of heat even on moderate power draw. But it all depends on how much redundancy manufacturer implemented in PSU design. So, without thorough understanding of schematics, it's a gamble.

Does the OEM fan not have a part number on that you can look up?

A modern fan, even if it's the same voltage and rpm is likely to be measurably quieter and still shift the same volume of air.

megatron-uk wrote on 2021-06-14, 22:35:

Does the OEM fan not have a part number on that you can look up?

A modern fan, even if it's the same voltage and rpm is likely to be measurably quieter and still shift the same volume of air.

Good thinking, thanks. The part number says df1202512SELN; now, there are a lot of branded and unbranded fans with that PN, and the rated CFM seems to be anywhere between 35 and 45. This gives me a great idea of what I'm looking for, which turns out to be less than I thought.

Do you really trust that ancient power supply to not try any of your components if it goes bad?

To top it off, the ripple is probably really bad compared to a newer high quality PSU which will lead to the power regulation and filtering circuitry on the motherboard, cards and drives to run hotter and wear out faster than need be.

cyclone3d wrote on 2021-06-15, 00:22:

Do you really trust that ancient power supply to not try any of your components if it goes bad?

To top it off, the ripple is probably really bad compared to a newer high quality PSU which will lead to the power regulation and filtering circuitry on the motherboard, cards and drives to run hotter and wear out faster than need be.

That is a good question. I have been arguing with myself about this, and could still be persuaded otherwise.

At a glance, common sense would also suggest me to go with a more recent PSU, but that doesn't necessarily make me at ease. There's always the likelihood for power supplies to go bad, I have seen it happen to garbage units as well as quality brands; this is something that causes me a bit of paranoia on my newer builds, on which I always go for 80 plus titanium rating if possible, but that would be a comically high expense for my retro rig. This means going for models with a lower rating, which gives me even less peace of mind, and would still require me to research a solution for the missing -5v rail.

I mean, I know that the best course of action would be to buy a new one, but I am struggling to justify the expense, especially when I've got a functioning one already; additionally, the system I'm powering probably doesn't come close to reaching the PSU's 70% capacity (P3 866 with TNT2 m64, Voodoo 2 and SB Live card with plans to add two other ISA cards for DOS, which is nothing too demanding), so it's not like I'm driving it too hard anyway.

It should also be said, however, that I have been experiencing weird behaviour coming from my garbage Sound Blaster Live card, such as sound occasionally coming out of one channel or inexplicable buzzing; this may be due to an awkward cable situation which I am planning to resolve (mainly by running it through a DI box, which I have done with success in the past), but the thought that it may be the PSU's fault for not delivering clean power is definitely rattling in the back of my head.

Welp, after some deliberation I have decided to go for the fan swap after all; this is only because I remembered having a perfectly good Silent Wings 3 just sitting around, and the operation came at no extra cost for me. I might still end up getting a proper passive PSU in the future, as it's still an audible affair, but for now I'm all settled for free, no less.