SCSI cable nightmare

My configuration is as follows:

Windows XP Pro
Asus A7V266-e (w/Raid)
AMD 1800 XP
Crucial 512 MB of PC2100 DDR
Western Digital 120 GB Caviar HD
Seagate 80 GB Barracuda HD
Plextor PlexWriter 24x10x40
Toshiba 8x DVD
Enermax EG465P-VE (FCA) 431W (power supply)
NVIDIA GeForce2 MX Display
Pinnacle DV-500 Video editing card
Kingston EtheRx KNE100TX PCI Fast Ethernet Adapter
Adaptec AIC-7850 PCI SCSI Controller
JazII SCSI Drive (External)
Nikon LS-2000 film Scanner (SCSI)
HP 722c InkJet
Alps 5000 Thermal-Dye Printer
Canon i950 Photo printer
HP 7490c Scanner

Problem:

I'm regularly destroying SCSI cables. With a new cable installed and the Nikon scanner connected, the scanner works perfectly. However, shortly thereafter, the system can no longer connect to the SCSI device. It doesn't matter if I connect the Nikon, Jaz, or HP 7490c SCSI device.

The only way that I can get it working again is to replace the cable.

Any suggestions?

Thanks,

JCC

<font color=purple> I doubt, therefore I might be </font color=purple>