A bit of a necro:

This 1999 PC is a fully 3x ISA equipped s370 MOBO with 20-pin power supply that supports -5v. It's also chock full of cards and disks.

Where can I get a semi-decent pre-ATX12V 2.x PSU? (no USA amazon links)

I see there is that PCI Voltage Blaster solution for -5v for modern supplies, and 24 to 20pin adapters, but I still need strong 3.3v/5v power, so modern PSUs probably won't cut it, since it's a 370 P3 build with multiple HDDs and GPUs and soundcards and some other stuff.

Why do you care so much about -5v? Do you really care about super early sound blasters?

kolderman wrote on 2022-12-11, 07:38:

Why do you care so much about -5v? Do you really care about super early sound blasters?

Frankly, this is my most period correct PC (mobo is maybe from 2000, but I got it for cheap and it's a fully pre-P4 board).

Now I'd take a new ATX supply over any 20 year old one without thinking, but look at it this way:

With a period correct ATX12v 1.x I can get everything I need - 20pin connector, beefy 3.3/5 rails, -5v, aka max compatibility, zero issues or hacks.
Now do not mistake that I actually want a 20 year old PSU - I just need ATX12V 1.x, no matter when it was produced.
And I have no idea what to search on Fleabay, I don't know of any good old brands, or if the new Chinese clones are even worth looking into.
In fact, I searched only like "atxv12 1.3" or "retro pc power supply" - bunch of brands I never heard of, and most of them sound extremely Chinesium.

On the other hand, a modern ATX PSU has only one issue - it lacks beefy 3.3/5v rails. I can get a 24-20pin adapter, I can get the ISA Voltage Blaster, but the most important thing is the wattage on those rails, the core of "will my PC even boot or be stable".

I neither have the money nor the will to gamble with say a 650w modern PSU that won't work, or buying that Chinesium crap that might explode.

Basically new (and not a Chinesium clone) ATX12v 1.x > new modern ATX12v 2.x/3.x with strong rails > old/used ATX12v 1.x.

This worries me, too.

My current plan (pun intended) is to keep a small collection of old ATX 1.x PSUs
and refurbish them, as needed.

Things like caps and diodes can easily be replaced, many mosfet types can be replaced, too.

So if the design of a particular ATX PSU is fine and merely the installed parts are cheap/faulty,
then I see no reason not to "rebuild" such a PSU on two or three weekends.

Personally, I make no difference between an 1980s PSU of a home computer, an AT and ATX PC anymore.
They're all equally outdated, obsolete. So why not just simply repair them and leave them in charge (pun intended)? 😃

Jo22 wrote on 2022-12-11, 10:54:

My current plan (pun intended) is to keep a small collection of old ATX 1.x PSUs
and refurbish them, as needed.

Soldering a cap is one thing, refurbishing a high voltage component such as PSU is a bit next level.
It also creates a "hobby inside a hobby" with all it's drawbacks.
And you can only refurbish it for so many times...

Still, you have the problem as I do - which (and where) PSU to get?
I dunno even what to google, and I'm frightened of those "YongPak7ATX-3000" Chinesiums unless someone has good things to say about it, and even they don't have good rails from what little I've seen on Fleabayou.

At least 20A on the +5V rail should be good enough, PIII CPUs doesn't strain it much like AMD Athlon CPUs. -5V isn't relevant if you don't intend to use any early Sound Blaster ISA sound card, PAS16 or the Roland LAPC-I.

I've had not horrible luck with FSP/Sparkle/Fortron. They're Taiwanese, so not explicitly cheap chinesium. My understanding is that they make PSUs for lots of companies, and a lot of PSUs you'd be looking at appear to be either NOS or freshly made for industrial legacy applications.

Although looking at their offerings now, it's looking like their 3.3V and 5V rails have the same "total output shall not exceed XXX Watts" as most PSUs have. Seems to range between 85W to 130W for them. But you may find something that lines up for you. Here is the datasheet for the version I have a few of humming in machine. Might serve as a good starting point for you. Allegedly someone on Amazon is still selling them for $60... but I wouldn't buy mine from there.

http://www.sparklepower.com/pdf/FSP300-60ATV.pdf

I've gone through all 3 of the main "Time Machine" Builds (Still have my 233mmx and K63+ Build), and I still always return to the C3 Nehemiah. A 1200mhz Model will clock to 1400 which Is equivalent to a Athlon TB 800mhz. If you get a Gigabyte BX board you can do all adjustments in Software.

I went pretty all in with my C3 build and its pretty well spec'd for the games I'd like to play.

My Build Consists of the following

VIA C3 Nehemiah 1.2ghz (Hosted on a MSI Master v2 Sloket)
Gigabyte GA-6BXC Rev 2.0 Intel BX Motherboard
512mb Ram (2X256mb) Crucial CAS 2
3DFX Voodoo 3 3000 16MB AGP
Matrox M3D Power VR PCI Accelerator
Sound Blaster Audigy 1 (This Handles Win98 Stuff, But also acts as a mixer in DOS)
Sound Blaster AWE32 CT3980 With 28mb Ram (OPL3/EMU8000 Through SPDIF into Audigy. All Analogue volumes muted except for Digital Sound which is fed into Line-In on Audigy)
Terratec EWS64XL 16MB Ram, Breakout Box hosts Yamaha DB50XG. All this is passed though SPDIF into the Audigy, MIDI 2 is used to host some Midi Modules.
MPU-401 with Korg Trust SuperSound Wavetable Module - Audio is passed into internal AUX header on Audigy
Sandisk 128GB SSD using a SSD/IDE Adapter
External Modules - Roland MT-32, Roland SC55, Yamaha MU50, Korg NS5R with Dreamblaster X2 in the internal Wavetable header, Miditech Pianobox USB.

This works really well! I obviously went a bit nuts on sound but I do like my sound and it covers a good range. If I use External Modules I have the audio passed out the Line Out of the Audigy into a mixer where the external modules are connected.

I'm currently working on my Software configuration. I have Win98SE installed, but I set it to boot to DOS where I am configuring a menu

DOS Performance - CPU set to 1400mhz and MTRRLFBE Loaded for improved VGA performance
DOS Slowdown - Loads minimal where I can set the required parameters for fussy games
Load Win98 - Loads Windows 98.

And that's what I ended up with on my Journey for a broad spectrum 98 build.

2mg wrote on 2022-12-11, 12:52:

Soldering a cap is one thing, refurbishing a high voltage component such as PSU is a bit next level. It also creates a "hobby in […]
Show full quote

Jo22 wrote on 2022-12-11, 10:54:

My current plan (pun intended) is to keep a small collection of old ATX 1.x PSUs
and refurbish them, as needed.

Soldering a cap is one thing, refurbishing a high voltage component such as PSU is a bit next level.
It also creates a "hobby inside a hobby" with all it's drawbacks.
And you can only refurbish it for so many times...

Yes, I don't deny that. However, I already did these things before, otherwise I wouldn't mention it. ;)

In addition, PC PSUs are very mature.
They have a so-called "power good" circuitry and, -normally-, do shut down if just the slightest thing is wrong.

That's why PC PSUs are used for a sorts of other things.
People in the amateur/CB radio scene use them for their strong 12v line, for example (transceivers, linears).
Despite the fact that 13,8v should be used for these things (undervoltage causes a wrong working point of the final transistors). But that's another story. ;)

That being said, repairing PSUs is a serious matter.
Cheap switching PSUs or old transformer PSUs without protective circuits (fuses or immunity against shorts+automatic power off, overssurge protections etc) are dangerous.

Hence, laboratory PSUs are much safer to thinker with.
They're kind of intelligent and meant to be fixed (by service personnel, but that's another story).

Edit: Of course, there are bad ATX PSUs, as well.
Everyone who's serious about the hobby should get a PSU tester (imho).
It's a basic tool, just like a multimeter or an ISA/PCI POST card.
For about ~20€, a version with an LCD display can be obtained.
It can measure both ATX and Molex connectors. 🙂

I have plans and parts, should I ever get a respite from calamities major and minor to bring them to fruition, to do "so low it's limboing in hell" IBM MX686 PR 266 on a Lucky Star 5V-1A for 7mhz to ~250, then the K6-2+ modded to +3 on a P5A or GA-5AX depending on which behaves better for me, which will manage 2x50 to 5x124 maybe, then a mobile modded athlon that will do 300-2000ish, got choice of boards for that, will be toying with best win98 compatibility and what works with CM PCI sound best for DOS. Video selections not set in stone, could be anything from Virge, Voodoo3, Permedia, Rage 1-128, Radeon 7-9000 and/or Geforce 2 of some flavor.... and if 7Mhz on the bottom ain't covering it, proceed into turbonated XT board build with a "PC-Sprint" accelerator build switchable to at least 3 speeds with a V20. But I have the luxury of having a huge stash to play with, not having to get everything on eBay at $100 a piece.

2mg wrote on 2022-12-11, 10:29:

Frankly, this is my most period correct PC (mobo is maybe from 2000, but I got it for cheap and it's a fully pre-P4 board). […]
Show full quote

kolderman wrote on 2022-12-11, 07:38:

Why do you care so much about -5v? Do you really care about super early sound blasters?

Frankly, this is my most period correct PC (mobo is maybe from 2000, but I got it for cheap and it's a fully pre-P4 board).

Now I'd take a new ATX supply over any 20 year old one without thinking, but look at it this way:

With a period correct ATX12v 1.x I can get everything I need - 20pin connector, beefy 3.3/5 rails, -5v, aka max compatibility, zero issues or hacks.
Now do not mistake that I actually want a 20 year old PSU - I just need ATX12V 1.x, no matter when it was produced.
And I have no idea what to search on Fleabay, I don't know of any good old brands, or if the new Chinese clones are even worth looking into.
In fact, I searched only like "atxv12 1.3" or "retro pc power supply" - bunch of brands I never heard of, and most of them sound extremely Chinesium.

On the other hand, a modern ATX PSU has only one issue - it lacks beefy 3.3/5v rails. I can get a 24-20pin adapter, I can get the ISA Voltage Blaster, but the most important thing is the wattage on those rails, the core of "will my PC even boot or be stable".

I neither have the money nor the will to gamble with say a 650w modern PSU that won't work, or buying that Chinesium crap that might explode.

Basically new (and not a Chinesium clone) ATX12v 1.x > new modern ATX12v 2.x/3.x with strong rails > old/used ATX12v 1.x.

-5v is only needed for a couple isa cards that I know of like media vision, and gl finding a psu not made in china.

Warlord wrote on 2022-12-12, 05:48:

-5v is only needed for a couple isa cards that I know of like media vision,

I know. Tho some boards apparently don't boot or work differently without it.

I see that there is the Voltage Blaster, and apparently there are some connectors that I believe either have DC-DC converters, -/+ inverters, or step down converters, tho I have no idea what's in Vogons' drawing board, and what actually exists, apparently some stuff that worked got nixed in the recent years even on Ebayeoux.
Any pointers on the best solution here?

and gl finding a psu not made in china.

You mean a new one that has -5v that's not made in China, or a new ATX 1.x in general that's not made in China?