Does it do it without the keyboard?
Edit: or the ps2 - at adapter is broken.

Sounds like something is stuck on the keyboard circuit.

1. try cleaning the keyb socket, could be something stuck inside
2. all pins must lead to the keyboard controller, one is pin#94 (clock); another pin#93 (data), another is ground and last is +5V

use this to find pins 93 and 94. if no continuity = broken trace somewhere or bridge somewhere
https://theretroweb.com/chip/documentation/pc … e7758740048.pdf

it's PC87306, close to the 1st pci slot

Thanks for the reply. It makes the same beeping sound without the keyboard connected. I have tried cleaning the keyboard port. Also, tried multiple keyboard adapters and confirmed that there is 5V on the 5V pin.

I'll try checking continuity between the keyboard port and the I/O chip. Might need some smaller probes for my multimeter since I don't think I can hit an individual pin with the current probes.

I have\had the same problem with a 440bx motherboard, I wasn't able to understand what the problem was, but surely it wasn't due to the keyboard or the the keyboard controller.
Are the caps looking good? Do you have any ide cable connected?

uniracers wrote on 2025-01-19, 01:30:

Might need some smaller probes for my multimeter since I don't think I can hit an individual pin with the current probes.

Not a problem, you just need to hear it beep. Unless you have humongus probes 😀
I have this motherboard. Imma go give it a check to see what it says on the keyboard side.
Did you set correctly all jumpers? Tried a different cpu?

Could you post pics HQ of your board and the upper left corner where the keyboard connector is?

Nemo1985 wrote on 2025-01-19, 03:28:

I have\had the same problem with a 440bx motherboard, I wasn't able to understand what the problem was, but surely it wasn't due to the keyboard or the the keyboard controller.
Are the caps looking good? Do you have any ide cable connected?

I'm not seeing any caps that look suspect. I do not have any ide cable connected

Nexxen wrote on 2025-01-19, 12:10:

Not a problem, you just need to hear it beep. Unless you have humongus probes 😀
I have this motherboard. Imma go give it a check to see what it says on the keyboard side.
Did you set correctly all jumpers? Tried a different cpu?

I checked continuity between the data and clock inputs on the port and the corresponding pins on the I/O chip, and it seems to be okay. There aren't really any jumpers on the board as far as I can tell other than the one to clear the CMOS. I only have the one socket 7 CPU, but I could look into getting another one if it seems like possibly a CPU issue.

Here are the pictures I took:

Something interesting I noticed when poking around with my multimeter is that there is continuity between the two left-side legs of the keyboard port. I'm not sure if that's supposed to be the case.

uniracers wrote on 2025-01-19, 22:24:

Is the middle pin of the keyboard connector beeping on pin#93?
On mine it is.

Pinout of the keyb connector:

from left to right:

[3] (no connect) --- left
[5] (+5V / continuity with power connector and should beep) ----
[2] Data ( connected to pin#93) ----- middle
[4] Ground -----
[1] Clock (connected to pin#94) --------- right

Can you check again if [2] is in continuity with pin#93?
Path: [2] connects to RN50 (472 value = 4.72Kohms can you check if it is that value?)
connects to FB2 (to grounds it reads 5.96Kohms) and the cap under C73 (is it reading some resistance?)

(all these are in the corner around the power connector)

uniracers wrote on 2025-01-19, 22:24:

https://i.ibb.co/yQWDXfT/IMG-2226.jpg […]
Show full quote

There shouldn't be any continuity between those two, they are Clock signal and Ground. On mine I have close to 6Kohms
Could you check again by using a screw hole as ground?

Check RN50 and C73 if they are both shorting to ground.

If you have the adequate tools you could try to use the USB connector with a USB keyboard.

usb connector:

J8: G / P0+ / P0- / x / +5V
J9 G/ P1+ / P1- /x / +5V

X = no pin

https://theretroweb.com/motherboard/manual/43 … 1a947875110.pdf

Tha manual is basically good for this one too, even if for the jumper version.

Nexxen pretty much covered anything I could think off. Sorry have nothing more to add other than IMHO the Explorer series of QDI have lots diff issues over time.
Have the QDI Explorer i430VX/250DM 3.0 (s3.1) and is NON jumper like yours and it can be a pain even working properly....

Oh wait, just looked at the picture !! You do have a 3.0 (s3.1). What BIOS are you running ?
added: and what CPU ? my board hates DIMM memory so using 72pin

Horun has a good point - VX chipset motherboards often have issues with SDRAM DIMMs. My VX board wouldn't work with SDRAM but it works fine with EDO SIMMs.

Nexxen wrote on 2025-01-19, 23:23:

There shouldn't be any continuity between those two, they are Clock signal and Ground. On mine I have close to 6Kohms
Could you check again by using a screw hole as ground?

Check RN50 and C73 if they are both shorting to ground.

I checked the resistance between both the clock pin and ground pin on the connector and between the clock pin and the screw hole, and I'm seeing a reading of around 11-12 ohms.

Where would I put the multimeter probes to check if RN50 and C73 are shorting to ground?

uniracers wrote on 2025-01-20, 19:11:

Nexxen wrote on 2025-01-19, 23:23:

There shouldn't be any continuity between those two, they are Clock signal and Ground. On mine I have close to 6Kohms
Could you check again by using a screw hole as ground?

Check RN50 and C73 if they are both shorting to ground.

I checked the resistance between both the clock pin and ground pin on the connector and between the clock pin and the screw hole, and I'm seeing a reading of around 11-12 ohms.

Where would I put the multimeter probes to check if RN50 and C73 are shorting to ground?

What about pin2 (data) and ground? Does it go up to pin#93?

On the sides of the components.

Resistance network are like this

x1---x1
x2---x2
x3---x3
x4---x4

Where each input has an output right in front of it (it's just 4 resistances in 1 component, to save space I guess).

C73 on the sides as well.

12 ohms isn't good at all, range should be in kilo ohms. Well, close to the end. Hope I was right.

Do you have a soldering iron, hot air station?
You can remove the C73 to check, for the RN it's a little more complicated but if you have hot air it's fast. No hot air, just add a lot of solder on the sides and keep the iron tip (big one) on top.

Between pin 2 and ground, I'm getting around 40 ohms. It seems like there is continuity between pin 2 on the port and pin 93 on the I/O, but it is hard to tell that I'm only touching pin 93 since the pins are so small.

I attempted to check the resistance of RN50 and got a reading of around 800 ohms. I didn't get any reading with C73.

I do have a soldering iron, but no experience working on circuit boards. Don't have a hot air station.

Desolder RN:
https://www.youtube.com/shorts/vSf66LLiUgA

Other componetns:
https://www.youtube.com/shorts/Fjm_mNS2rIA

It's no that difficult. If you have some scrap board do some exercise first to grasp the process.

uniracers wrote on 2025-01-22, 02:14:

Between pin 2 and ground, I'm getting around 40 ohms. It seems like there is continuity between pin 2 on the port and pin 93 on the I/O, but it is hard to tell that I'm only touching pin 93 since the pins are so small.

I attempted to check the resistance of RN50 and got a reading of around 800 ohms. I didn't get any reading with C73.

I do have a soldering iron, but no experience working on circuit boards. Don't have a hot air station.

Probably the RN is faulty. The stroke signal is present even without any, and this leads me to believe RN50 needs replacement.
C73 is in kilo ohms. Sometimes the oxidized solder is preventing readings, try scratching it a bit to reveal the solder underneath the surface.
Otherwise it's a dead component that needs replacement as well.

I'd replace the RN50 before anything else, just by removing it you can have an answer to this problem. It stops, then that's it.

In pic is path of the signals.

Can you measure C73 and the one below?
You can use some wire tied to the probes if they are big, it is not going to affect the resistance readings (or even just use your fingers to keep on).
I used whatever was sharp before buying some needle probes and it worked well.

To me RN50 or C73, C74 are bad.

If a cap fails it can become more of a resistance and pulling the signal to ground.

The RN50 can go bad, I had it before as others. 472 is a common value, even if you buy 100 on some site it's not going to be costly.

The other 2 legs of the RN50 are connected to the PS2 connector circuit.

Edit: the red line coming out of C74 is a mistake I forgot to delete and didn't bother after seeing (lazy a$$ today 😀).

@Nexxen Thank you for all of your help on this. Sorry, it's been a few days since I've been able to get back to this.

I measured the resistance across C73 and C74. I'm getting 10 ohms for C73 and 40 ohms for C74. Side question: I thought it wasn't possible/accurate to measure resistance when the components are in circuit?

Incidentally, I have another one of the same exact model board. I measured C73 and C74 on that board and was getting readings in the kiloohms. The issue with that board is that I get no video output (using the same video card, CPU, and RAM as the board with the keyboard issue), and there is no post beep. It does seem the board gets power because the CPU fan comes on. I thought I was closer to a fully working board with the one that has the keyboard issue.