#A3000 Scsi Problem HELP!
4 messages in this thread
Dean:
Thanks for the informative description of the SCSI termination. On my system, I
would guess that I would HAVE to disable the TERMPWR on my SCSI-2 drive, since
I cannot turn off the termination power on my controller.
The drive comes with small resistors that install near the SCSI connector, but
still has the TERMPWR jumper. There is no "TE" jumper, since the resistors are
removable.
I have changed system cables from a 6' relatively narrow cable to a very thick
3' cable (28 AWG), and so far, the system is behaving without a hitch, even
using synchonous transfer. So, perhaps the real problem was the length and
quality of the connector cable…
Thanks for your help!
— Dave
Dave,
You can, and probably should since you have the option, set your drive
so it gets TERMPWR from the host adaptor. This is the best way since it
makes certain that the terminators are powered even if the drive is not.
It's seldom that you'll find a drive with both active and passive
terminators. Yours has the passive type.
A bad cable can cause all kinds of grief, and it's the hardest kind of
problem to detect. Also, a SCSI cable needs to be a 50 conductor cable
even if the connector on the controller is a DB25. The extra grounds act
as shields to reduce random errors.
Dean Brown
DKB
Dean,
Thanks again for all your help… very detailed.
The drive is set to get the TERMPWR from the host adaptor. I have replaced the
SCSI system cable, and have been running the drives in Synchonous Xfer mode,
with no problems yet. It seems I have found the culprit!!
The "old" SCSI cable looks too thin to be a true 50-conductor cable. The new
one is VERY thick and substantial. It seems to be working great.
Thanks again for your help!
— Dave
Dave,
Glad to hear everything is working better now. It's supprising how much
grief bad cables can cause!
Dean Brown
DKB