I have just upgraded my Asus motherboard to a Tyan Trinity KT-A (S2390B) motherboard. Everything is fine except when I do a Windowns ME shutdown. The ATX system shuts down normally but the keyboard and mouse are still powered on. (The Num light does not go off and the optical mouse light does not go off.) They powered off with the system with the Asus before, but they don't with the Tyan now.

I also notice that when I turn off the power supply's on/off switch the keyboard and the mouse do go off, of course. But, when I then turn the power supply's switch back on the entire system looks like it is powering on for just a second (the lights flash on and the fans start to spin, etc.) then it all goes off. (But the optical mouse light stays on.)

I have gone over all the jumpers and setting on the motherboard and in the system BIOS, but nothing seems to change this "problem." Is this a problem with the motherboard or is this normal for some systems? Will this harm the motherboard or any system components? By shutting down the system and then turning off the power supply switch, will this harm anything? Thanks for any help.

Well, I guess I'll have to answer my own post. :-)

Tyan is stumped, but with the help of Sarras I found that the PS/2 ports do keep powered up on some Tyan systems. (Tyan says this is supposed to be able to be turned off though. They are researching the "problem.") By switching the mouse to USB the mouse now correctly shuts off with a system shutdown. The keyboard still has power, but I turned the NUM lock "off" so there is no light on after a system shutdown.

The power supply switch on the Tyan ATX will do a brief "check" to the board by powering up the lights and fan (for a brief moment) when the switch is turned from "off" to "on." So, it's normal on this motherboard. I guess I can live with this work around.