Can you disconnect the Reset-Connector (Cable) from the Mainboard, and try again?

Unfortunately it does the same thing with no front panel connectors attached at all, seems to power on all by itself when switching on the PSU, without even shorting the power switch pins. Shorting the pwr-sw/reset-sw pins afterwards does nothing as well. I was testing the mainboard alone, without anything on it except for the CPU, RAM and the power connectors.

It probably will be a stupid question that i will do but i will ask anyway
The clear rtc(or cmos) jumper is set properly?

What voltage is on the POWERGOOD from the power supply?

Yes, try another power supply.

Another thing is, check CMOS battery. Disconnect it for some time, and make sure it is not empty and even try booting without battery.

Thank you for your responses. I have already tried both using different power supplies and replacing the CR2032/discarding it completely, but none of these attempts made any difference, and yes, the jumpers are all properly set. I'll play around with it a bit more tomorrow and report back.

psychz wrote:

Thank you for your responses. I have already tried both using different power supplies and replacing the CR2032/discarding it completely, but none of these attempts made any difference, and yes, the jumpers are all properly set. I'll play around with it a bit more tomorrow and report back.

I had a M2N that had this behavior and i solved by replacing some voltage regulators, so give them a check.

also try a replacement bios chip

Hello my friend! Have u resolve the issue with the reset signal????

keeper5511 wrote on 2024-05-22, 15:36:

Hello my friend! Have u resolve the issue with the reset signal????

This is for a totally different board, but I just fixed an issue with a 440BX that appeared "dead" suddenly, which I later realized had a stuck (shorted) reset button header.
Re: Two 440BX Board Issues: Dead WinTech\Edom W6BXA and a very picky SOYO SY-6BE+...

Long story short, holding the power and\or reset buttons with the board powered on fixed it for me, though in my case the board would not power on at all without shorting the green\black ATX wires (to force the PSU to power on), so it could be a totally different problem. Still, it drove me crazy for a couple of weeks until I found the solution, so I figured I'd give my input. 😀

psychz wrote on 2016-05-01, 13:48:

Happy easter! Here I have what appears to be a dead ASUS M2N-MX SE Plus rev 2.02g which is probably dead. It appears to power on (green led, cpu fan starts running, no beeps) as soon as I switch on the PSU, and when I connect a PCI diagnostic card it reads no POST codes at all, however it indicates all the voltages as available and the RST signal as stuck (reset led on the card is always on). The motherboard appears clean, with no broken traces, leaked/bad/blown caps or toasted-brownish chips. Pins are straight, nothing appears to be shorted... Clear CMOS/RTC doesn't help either. What might have been the cause of something like this? Is it something repairable or am I just tossing the thing altogether and keeping parts? Just asking because I have never seen a similar issue to this one before!

I just spent all week-end reviving a Socket 7 TX97-XE motherboard which was exhibiting the exact same issues. All required voltages seemingly present on the POST card, CPU gets warm, no post, no codes, reset line stuck on. After lots of hair pulling, I found that it would come out of reset only when I would apply a slight bend to the motherboard around the ATX power connector / CPU socket. I really hoped it was not an internal trace nor the chipset as no damage was obvious.. It turned out one of the power mosfets had its metal tab no longer soldered to the board.

So I de-soldered the two pins, cleaned them and the tab underneath, cleaned the motherboard pads, applied fresh solder and re-soldered it to the board. It's been rock-solid since.

Turns out that mosfet is the one that provides power to the CPU.. The pentium mmx is a dual-voltage chip, vcore and I/O voltages are seperate and both provided to the CPU. This mosfet is what outputs the 2.8V for the vcore. So my CPU was probably getting warm from the I/O voltage and I guess potentially erratic and occasionally present vcore.

I really ought to thank Bits und Bolts for the P2B repair marathon and also the video with the sporadically working PS/2 keyboard input. When I flexed the board and it would get out of RESET, I immediately thought of all the mosfets that became loose on the P2Bs and this was the first thing I checked after - and it was the culprit!!!