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Any sense buying modern PSU for old hardware?

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Reply 300 of 305, by Kasreyn

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I opened up a Zasilacz Akyga Basic 700W (AK-B1-700) and took some pictures.

Better let people judge these components for themselves. But please comment with opinions.
Whether or not they want this to be the keeper of their retro treasures 😁

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Reply 301 of 305, by Kasreyn

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HWMonitor readouts can't be trusted on my 8K3A (running from Akyga Basic 700W (AK-B1-700)). That 5.6V would be much outside ATX allowed +4.75 V to +5.25 V tolerance.

With a multimeter I can see the +5V rail drop from 4.9V to 4.82 after starting Prime95.
Also with multimeter.. 12.7V on the +12V rail, slightly naughty.

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Reply 302 of 305, by tehsiggi

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The S30C45F dual-diode rectifier is rated for 30A whole device - all of the rails are rated above 30A. That's a red flag already.

The attachment Screenshot 2026-10-28 at 19.12.34.png is no longer available

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Reply 303 of 305, by DaveDDS

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Not necessarily. You have to think in "effective Watts" (VxA)

In a switching PS the primary regulator is typically handelling 110v/220v mains ... 30A at 110v is 3300 watts. Disregarding effeciency thats equivalent to 660A at 5V, 275A at 12V etc. The sum of what you can draw at lower (PCish) volrages greatly exceeds the draw from mains.

I'd have to see a schematic and go through a bunch of specs to guess at reasoanle numbers, but assuming mains AC->DC for switcher inputs, I can see 30A being lots for a pretty high end supply (std mains here in N.A. is 110v at 15A(fuse/breaker)) and I've not seen a "personal" system needing even close to that.

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Reply 304 of 305, by Mondodimotori

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Kasreyn wrote on Today, 17:54:

With a multimeter I can see the +5V rail drop from 4.9V to 4.82 after starting Prime95.
Also with multimeter.. 12.7V on the +12V rail, slightly naughty.

Those are... Not great but also not terrifying.
I have a 462 MOBO without p4 connector and, with an Athlon 1400C + Enermax vintage PSU, I get those voltages readings from Everest. If I had a multimeter I would test them directly. System is rocksolid but, as said, it's a vintage PSU that was probably a decent unit 20+ years ago. Now? Not so sure.

But even then, on that system + the chinesium PSU that claimed 25A on the 5V and max rating of 180W, on Everest the voltages would drop down to 4.6, so well outside ATX standard. And yet the system would POST and I would game on it no fuss.

Reply 305 of 305, by tehsiggi

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DaveDDS wrote on Today, 20:56:

Not necessarily. You have to think in "effective Watts" (VxA)

In a switching PS the primary regulator is typically handelling 110v/220v mains ... 30A at 110v is 3300 watts. Disregarding effeciency thats equivalent to 660A at 5V, 275A at 12V etc. The sum of what you can draw at lower (PCish) volrages greatly exceeds the draw from mains.

I'd have to see a schematic and go through a bunch of specs to guess at reasoanle numbers, but assuming mains AC->DC for switcher inputs, I can see 30A being lots for a pretty high end supply (std mains here in N.A. is 110v at 15A(fuse/breaker)) and I've not seen a "personal" system needing even close to that.

That rectifier is for the secondary voltage. We're not talking the mains input rectifier here.

That one is used in any of the output rails and is rated at 30Amps max for both diodes together. And those rails are rated for more than 30A. So the math isn't working out. The current rating of the diode would be too low for any of the rails.

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