harddisk freeze on 2.4.20

Hi!
My current setup is A7V8x 2 WDC 180GB disks in raid0, both are masters
(without slaves) on the primary and secondary onboard VT8235 controller.
The drives are attached at the connector in the middle of the cable.

When doing a badblock scan of /dev/hda and /dev/hdc the primary master
disk freezes from time to time, i.e.
it is not accessible anymore/coldfreeze of the system ... even after
a cold reboot the bios complains "primary master fails".
A powerdown / poweron cycle fixes this.

I am not sure whether the reason is cable/DMA/bios of the harddisk/bios/or linux ide drivers. However to find out the exact cause of this problem I am grateful for hints on how to find out where the problem lies...

I already tried a different cable for the primary master disk... still the same problem occurs.

Thanks,
Soeren.