how do the caps look (specifically the large ones near the cpu)?

Hopefully it didn't die like my nf7 2.0 did.

Locked up / blank screen while idle, then was acting weird / pulsing fans and green LED when powering on- No POST.

Then when I was proving things to test voltages it started powering on as soon as the power was turned on on the PSU.

Something died in the PS_O N circuitry.

All caps are in good condition on both boards.

1.) I would try DDR333. Could also be a problem of using too aggressive timings. Does the instability show up in Memtest86 ?

When it comes to audio, does Mic input work at least? If nothing works then probably the audio chip is damaged.

Unless it was recapped, bad caps could also be a contributing factor.

2.) You probably killed it with ESD while fixing the BIOS problem. Having a diagnostic card would help.

I also have two dead KT133 boards that were bought dead (QDI, Biostar). I then got identical working boards cheap to make diagnostics easier. One day I will get to fixing them, but I'm afraid one needs also a digital oscilloscope to see what's going on. Caps look visually ok. If it isn't caps I would suspect a scratched trace somewhere. I ruled out broken BIOS chips/wrong BIOS.

I'm afraid when it comes to oscilloscope it would take something like Voltcraft ADO-5004 (500Mhz, 12 bit, 4 channels). That is a "cheap" 500Mhz oscilloscope. Then one could tap into PCI, FSB, memory.

What power supply do you use with the boards? Despite having the 12V connector do not underestimate the need for a good 5V rail on the NF7-S.

AlexZ wrote on 2026-08-03, 20:52:

1.) I would try DDR333. Could also be a problem of using too aggressive timings. Does the instability show up in Memtest86 ? […]
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1.) I would try DDR333. Could also be a problem of using too aggressive timings. Does the instability show up in Memtest86 ?

When it comes to audio, does Mic input work at least? If nothing works then probably the audio chip is damaged.

Unless it was recapped, bad caps could also be a contributing factor.

2.) You probably killed it with ESD while fixing the BIOS problem. Having a diagnostic card would help.

DDR333 goes well. I tried loose timings, but it still behaves weirdly. Tonight I'll do a few rounds of Memtest86.
I'll try the mic. The audio chip should be integrated into southbridge (Nvidia MCP-T - Soundstorm)
All caps seems fine, but maybe I will recap every one of them when I get some time.
That's too bad to hear that I killed it 🙁
Both PSUs have 40V on the 5V rail.

If DDR333 works then it could be a power delivery problem. What are those PSUs? It is cheapest to try yet another one. Only very old ones have 40A on 5V. Have you inspected inside? For memory power delivery you would have to inspect it with oscilloscope (a cheap one would do). Most likely just issue of PSU or caps.

I used to have a couple of nForce 2 boards and don't remember any problems with stability when 2 memory sticks were used. I sold them all and retested them for stability. I used just cas 3 I believe, so conservative timings.

For the A7N8X, what is it's behavior?

• Once you turn it on, does it instantly turn off again if you hit the power button or do you need to keep it pressed?
• What happens if you do not install any memory, will the board beep?

tehsiggi wrote on Yesterday, 08:04:

For the A7N8X, what is it's behavior? […]
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For the A7N8X, what is it's behavior?

• Once you turn it on, does it instantly turn off again if you hit the power button or do you need to keep it pressed?
• What happens if you do not install any memory, will the board beep?

Everything goes power on (HDD, green LED on A7N8X, and the southbridge is as warm as expected to be, etc.), but there is no POST beep and no video. The board does not beep at all, no matter which component I replace.
Sometimes it does instantly off, sometimes it does not.

It's going to be tough without second ASUS A7N8X Rev. 2.0. Having 2nd board would improve the odds significantly. You would typically 1.) check for missing parts (perhaps something broke off) 2.) check for scratches and verify trace conductivity if in doubt 3.) verify BIOS in working board 4.) have diagnostic status card displaying boot codes 5.) do thermal imaging to see if anything is overheating on broken board (a short somewhere) 6.) verify power delivery for RAM, CPU, signal quality (address, data) via oscilloscope and compare with working board. 7.) recap the board

I have another A7N8X, but it is deluxe, so BIOSes are different 🙁

SlowA wrote on 2026-08-03, 17:48:

1.2. No onboard audio

Jumpers at the audio front panel connector are set?

SlowA wrote on 2026-08-03, 17:48:

1. Abit NF7-S 2. ASUS A7N8X Rev. 2.0 […]
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1. Abit NF7-S
2. ASUS A7N8X Rev. 2.0

The board was working properly, although all of the options under Advanced (CPU/FSB/RAM/Voltage) were greyed out.

After a successful BIOS flash (confirmed), the board refuses to power on properly. I've reflashed the BIOS chip six times using a programmer (four official ASUS BIOS versions and two modded BIOS versions).

The board receives power, but there is no POST.

I'd try different CPUs and DRAM sticks. Try to set one dram stick to the left slot.

Yes...Tried all that already...no beep 🙁

SlowA wrote on Yesterday, 08:55:

tehsiggi wrote on Yesterday, 08:04:

For the A7N8X, what is it's behavior? […]
Show full quote

For the A7N8X, what is it's behavior?

• Once you turn it on, does it instantly turn off again if you hit the power button or do you need to keep it pressed?
• What happens if you do not install any memory, will the board beep?

Everything goes power on (HDD, green LED on A7N8X, and the southbridge is as warm as expected to be, etc.), but there is no POST beep and no video. The board does not beep at all, no matter which component I replace.
Sometimes it does instantly off, sometimes it does not.

Meaning also no beeping after a while without memory installed?