| From: | tim |
| Date: | 16 Aug 2000 at 19:06:53 |
| Subject: | Re: A3000 SCSI hard disk problems |
Hi Nick
>
> It is plugged in as per the old hard disk was, and i presume how Commodore
> assembled the unit itself, in that there is three connectors, the middle one
> plugged into the SCSI header on the m/board, and one longer length running
> out in front of the hard disk via the gap in front of the hard disk area,
> and a shorter one going towards the back of the A3000 into the hard disk.
> So:
>
> 1. 2. 3.
> +-+ +-+ +-+
> |#|--------|#|-----------------------------------|#|
> |#| |#| |#|
> |#| |#| |#|
> |#|--------|#|-----------------------------------|#|
> +-+ +-+ SCSI CABLE +-+
>
>
> 1 = Plugged into Hard Disk (where the older Quantum drive was)
> 2 = Plugged into A3000's SCSI 50pin header
> 3 = Spare, runs out to the front of A3000, above drive shelf.
That isn't right - it leaves both ends of the SCSI chain unterminated, with
the termination in the middle! A3000s often work like this, until suddenly
you change something of no significance, then it decides not to work.
>
> There is no sign of any resistor packs on the motherboard behind the SCSI
> header, i couldn't remove the drive shelf because it's such a pain in the
> rear, but I'm guessing all are empty, because two of them are. Is this good
> or bad? :) If i do need this then i proves one thing, Amigas really are
> girlfriends, always wanting your money...... :))
If 2 are enmpty, it's fairly safe to assume that the other is too.
What this means is that one end of the SCSI bus isn't terminated. As before,
many A3000s work like this, but it isn't strictly correct.
>
> > If not, then using a terminator on the external SCSI port may help.
>
> So if i was to get a passive or active terminator for the SCSI port, then
> that could help, or more prefrably would that solve this SCSI bus lock up?
A passive terminator would probably do for this configuration.
>
> Thanks for the help. I'm going to try and fiddle with the SCSI cable
> now.... :)
>
> Ok, just tried changing the cable as per the above diagram, connector one
> was attached to the SCSI header, Con. 2 to nothing and Con. 3 to the hard
> disk. SCSIMounter reports no change at all, yet placing the Quantum drive
> on Con. 3, worked! Grrr!
It's sounding more and more like a problem with the drive itself...
Tim
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