Tyan Tiger MP power oddity + no boot

[Cat]

I installed a new Tyan Tiger MP motherboard yesterday, into an Antec 1035 case, and it powers up regardless of whether the power switch from the case is on, or even attached to the motherboard header. I can toggle the PSU switch to turn it on and off, and SOMETIMES hold the case switch for 4 seconds to power down.

I'm thinking that something is wrong with the motherboard, as it is NOT supposed to power up without the power switch from the case attached and on. I thought only old AT motherboards powered on when the PSU was plugged in.

Using 2 1.4 GHz Athlon MP processors, assuming that they work correctly. Will check them individually tomorrow. Even if they were dead, it still wouldn't explain why the motherboard powers up without the switch.

I've tried a better (400W) power supply, different case, and still get the same result. The CPU fans spin up, as well as the PSU fan. Nothing else happens, no beeps, nada. I've switched out the RAM, video card, and hard drive. Everything from a bare boot to all peripherals installed still gets me nowhere.


So, to recap:

PSU unit ON -> motherboard on -> CPU and PSU fans spin up, hard drive, CD-ROMS power up -> No boot.
no case power switch attached
case power switch off

Any thoughts?

 

[Cat]

The processors have been confirmed to work in a separate motherboard, but the problem with the original setup remains.

 

[DiamondFire13]

My first instinct is that it is a motherboard problem. Do a search on the web, and you will be able to find which pins on the PS cable will turn it on. You can stick a paperclip in them and it should power on, and then pull the paper clip out and it should turn off, or somthing along those lines. If that works OK, then it is most likely your MB

Paul

 

[Cat]

Yeah, connecting the green and black leads will tun on my PSU. Why does my motherboard automatically power on without the header pins from the case? Who knows. Maybe someone else reading this will know.

 

[bozo1]

My Tiger (and Thunder) did the same thing but it worked fine. I think it's just a quirk with the board.

Do your basic troubleshooting.

Pay close attention to the jumper settings as the manual is poorly written and many people are jumping things backwards. (including me at first which I've never done with another board)

Make sure your memory is seated WELL. Crucial sticks seem to not want to seat well in these boards. Try one stick at a time, different slots, etc.

Clear your CMOS. This has taken care of non-POST problems for many people.

Remove all cards. Have nothing installed but your vid card and see if it posts.

Remove the mobo from the case to make sure something isn't shorting out somewhere, etc.

You are using Registered RAM aren't you?

 

[Cat]

Yep, PC2100 registered DDR from Crucial. Time to reseat it for the umpteenth time Thanks for letting me know your other MP boards had the same quirk, it'll save me a bit of time.