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Modern PSU on EP-7KXA Motherboard, will it work?

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First post, by gaffa2002

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Hi again everyone.
Lately I'm having a bit more time to get back playing with retro hardware and I'm planning on putting my classic PC back in action. Thing is, at the moment I only have an older ATX PSU which works, but I'm not sure if it's safe to continue using it or not. That's why I want to replace it by something (hopefully) new.

As far as I know, some older hardware have problems with new ATX PSUs due to lack of -5v rail, amongst other things. Does anyone know how can I check that in my specific setup?

Basically I'm searching for a PSU replacement to an EP-7KXA motherboard, it does have an Athlon 750mhz CPU (Slot A) and also a Sound Blaster AWE64 card connected into its only ISA slot, the AGP slot has an Nvidia Geforce 4 MX440 card. May I just purchase any modern ATX PSU and get adapters for the different connections or better not?

Thanks in advance.

Last edited by gaffa2002 on 2025-07-23, 20:17. Edited 1 time in total.

LO-RES, HI-FUN

Reply 1 of 5, by dominusprog

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Some older Sound Blaster cards need the -5V for amplifier circuit I believe. You can check for yourself to see if your AWE64 card have the pad for -5V contact.

The attachment ISA_Bus_pins.png is no longer available

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A-Trend ATC-1020 V1.1 ❇ Cyrix 6x86 150+ @ 120MHz ❇ 32MiB EDO RAM (8MiBx4) ❇ A-Trend S3 Trio64V2 2MiB
Aztech Pro16 II-3D PnP ❇ 8.4GiB Quantum Fireball ❇ Win95 OSR2 Plus!

Reply 2 of 5, by gaffa2002

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dominusprog wrote on 2025-07-23, 19:02:

Some older Sound Blaster cards need the -5V for amplifier circuit I believe. You can check for yourself to see if your AWE64 card have the pad for -5V contact.

The attachment ISA_Bus_pins.png is no longer available

Thanks for the response, it seems my sound card does not have the pad for -5V. Does that mean I can use any modern ATX PSU? Or there are other things to consider?

Last edited by gaffa2002 on 2025-07-23, 19:46. Edited 1 time in total.

LO-RES, HI-FUN

Reply 3 of 5, by dominusprog

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gaffa2002 wrote on 2025-07-23, 19:35:
dominusprog wrote on 2025-07-23, 19:02:

Some older Sound Blaster cards need the -5V for amplifier circuit I believe. You can check for yourself to see if your AWE64 card have the pad for -5V contact.

The attachment ISA_Bus_pins.png is no longer available

Does that mean I can use any modern ATX PSU? Or there are other things to consider?

No, go ahead and install your PSU 🙂.

Duke_2600.png
A-Trend ATC-1020 V1.1 ❇ Cyrix 6x86 150+ @ 120MHz ❇ 32MiB EDO RAM (8MiBx4) ❇ A-Trend S3 Trio64V2 2MiB
Aztech Pro16 II-3D PnP ❇ 8.4GiB Quantum Fireball ❇ Win95 OSR2 Plus!

Reply 4 of 5, by randi

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I run a 1980s IBM 5160 off a ATX, it works fine .

I think modern ATX PSUs dropped the −12 V negative supply, but thats only important for certain legacy RS-232 serial port applications.

Reply 5 of 5, by gaffa2002

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dominusprog wrote on 2025-07-23, 19:45:

No, go ahead and install your PSU 🙂.

randi wrote on 2025-07-23, 19:49:

I run a 1980s IBM 5160 off a ATX, it works fine .

I think modern ATX PSUs dropped the −12 V negative supply, but thats only important for certain legacy RS-232 serial port applications.

Nice! Thanks guys!

LO-RES, HI-FUN

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