The *size* might be the problem -- the PB1400 controller can't cope with partitions over 8.2GB. This is allegedly smoothed over in 8.6 and 9 but I would strongly advise partioning it and reformatting it, at a minimum making the boot partition 8GB or less and seeing how it copes with that. You might consider splitting it into 5 portions to make all partitions under that size.

If that doesn't fix it, I suspect hardware. The fact the drive is non-Apple has nothing to do with it; my own 1400 has a Toshiba OEM hard disk. But it's only 4GB