Not all SiS chipset Socket 3 PCI motherboards can take EDO, it depends on both BIOS version and chipset revision. Are you sure you are using FPM memory?

You can also try moving the video card to another slot, I have more than one motherboard that wont run the video card in the first PCI slot.

Also as this is 486 aka Twin Peaks era hardware there is no guarantee that just because a video card works in one motherboard it will work in another.

Have you tried a PC-Speaker? Coin cell is new?

Well, those are NEC FPM 6mb chips:

http://www.memoryten.com/p/004786.htm

So the memory does not seem to be a reason.

I tried speaker (I tried to connect it in various ways), but it remains silent, less the setting when it beeps constantly. I couldn't find any pinout description in the manual.

Now, I tried switching graphics adapter to all three PCI slots, no success. The card is Number Nine Motion 331 (s3 Trio).

The button cell is like new.

All the keyboard lights are ON (no blinking) from the very moment the PSU is turned on.

I have noticed that the processor is getting quite hot as soon as the PSU is turned on. I don't know if that's a proper behavior.
🙁

try isa graphics? compatibility is much better

Well, those are NEC FPM 6mb chips:

http://www.memoryten.com/p/004786.htm

So the memory does not seem to be a reason.

sry thats totally wrong logic;

Could you explain any further? Do you think it's the memory to blame? What kind of memory do I need to get then?

i'm not saying its bad; but you cant exclude it right; if you have another module to check with, i'ts definitely worth the time imho

OK, I will ask the seller to send me the memory he used testing the board. I Hope this helps.

The PC speaker connects at the top left, the header with 4 pins. There should be a text 'SPKR' or similar next to it.

Do you have more than one power supply to test with?

If you start the system without memory, do the keyboard leds also light up?

I removed all memory and keybord lights remain lit just the same way. I still have two other PSU so I could check tomorrow. But this one (200w) works with 4dps with no problems.

Maybe this will help: I had similar problems with posting while I connected some socket7 mobo with amd k5 lately to this PSU. And this mobo was fully funtional, I suppose. I gave it to my froend already so cannot check again. Generally, the only mobo I got to work was this small tomato... I tried three different graphics adapters.

Just out of curiosity, is the CPU in correct orientation? 😀 I recently put one in the wrong way and the system wouldn't even turn on.

I put the mainboard in the case with another PSU.

Without memory installed and without graphics it still behaves in the same way: keyboard diodes are permanently lit.

So I guess we can eliminate bad PSU as a reason of the problem as well 🙁

I''m checking out the CPU direction 😀 There is a dot on the CPU and there is one on the side where the hinge is located, so I guess I was putting it just OK 🙁

Running computer without CPU produces the same effect with keyboard diodes lit.

Found it! It was simply a missing jumper setting synchronous/asynchronous clock.

Just checked... now I have TWO fully functional ATC-1452B... ;--) (EDIT: fortunatelly (not), the first one still shorts the PSU sometimes, so I can explain getting the other one to myself)

tikoellner wrote:

Found it! It was simply a missing jumper setting synchronous/asynchronous clock.

Just checked... now I have TWO fully functional ATC-1452B... ;--)

just 🤣, but congrats on finding that 😀

Is that a PS/2 mouse header next to the keyboard port? Can you provide a copy of the official manual?

Unfortunaltely I did not get any manual with any of the boards. The only one I have found is this: http://www.elhvb.com/mboards/a-trend/1425b/ATC-1425B.html

Which obviously is incomplete (there should be some schematics, as the manual suggests).

I will give the header a closer look when I get back home, but I don't belive it's a PS2 connector, as the manual does not mention this.

What else could it be? 5-pins with a 1-pin gap, right next to the keyboard connector. All my experience with these motherboards points to a PS/2 mouse header. There is also a PS/2 mouse capable keyboard controller on this motherboard. Sometimes the PS/2 functionality is not documented.

I looked at the motherboard itself and this feature is not described anyhow. I will try to use it with PS2 mouse when I get one next week.