IDE IRQ weirdness on KT266A mobo


I’m getting flummoxed on this one, maybe one of the TM has seen this before?

Here’s the deal… Brand new mobo, a cheapie board (Jetway under another name I think). KT266A chipset, running a T-Bird 750 and 256MB of PC133 SDRAM (the board supports SDR and DDR).

The system does not seem to want to assign IRQ 15 to the secondary IDE channel. If I assign any devices on the secondary channel, I lose the primary, which is on IRQ 14, or course. The onboard IDE is enabled, Win98 sees both IDE channels, but as soon as I put a CD-ROM or CD-RW on either the secondary master or slave, that’s all the system will see - the primary is not available. The BIOS startup sees all the drives fine, autodetects no problem. The IRQ assignment list that the BIOS flashes up as part of the startup process shows only IRQ 14 assigned to “IDE controller”

I tried disabling and re-enabling the secondary IDE in BIOS, then the frickin video card grabs IRQ 15, and it does show up in the BIOS IRQ assignment at startup, as “Display Controller”, of course :smack:

Win98SE is installed, but this problem was occuring even when I was booting with a Win98 emergency boot floppy before the hard disk was FDISKed. If I removed the secondary devices, FDISK would see the hard disk. If I added either CD drive to the secondary, FDISK would claim there were no fixed disks present.

Win98 has all the latest and greatest 4-in-1 drivers, BTW…

Anyone got a clue on this? I’m schtumped!


A couple things to try here. Your BIOS may allow you to assign a particular IRQ to any device. Also, are you certain that when you attach the new drive that it is not set the same as your main hard drive (master/slave)?