In article <4372c5e7@212.67.96.135>, Dave <nospam@nowhere.com> wrote:
>Triffid wrote:
>
>>> Thanks for that.
>>>
>>> I checked and found the disk was already jumped SE. I removed the
>>> jumper (what else to try?) but no luck. I tried a few other jumpers,
>>> but no improvement.
>>>
>>> What was odd though is that
>>>
>>> a) The disk is seen if it is the *only* disk in the machine.
>>>
>>> b) The disk is seen if it the lower slot (SCSI ID=3), but not if its
>>> in the upper one (ID=1). And no, there are not any jumpers installed
>>> on any of the SCSI ID select pins.
>>>
>>> Anyway, it is at least semi-resolved. I've put an operating system on
>>> it and it boots OK now. Just needs to be in the lower slot, otherwi4>>> it can't be seen on the bus.
>>
>>
>> That's rather odd. There is no physical or logical difference between
>> the upper and lower drive bays aside from SCSI ID AFAIK.
>
>Yes, I thought it odd too.
>
>> I suspect your upper bay is b0rked somehow, and won't work with any disk
>> as a result.
>
>That is not so.
>
>Here you can see the Compaq disk that presents me trouble in the lower
>slot (ID=3) and a Seagate one in the top one (ID=1)
>
>
>ok probe-scsi
>Target 1
> Unit 0 Disk SEAGATE ST39103LC 0001LS482885
> Copyright (c) 1999 Seagate
> All rights reserved
>Target 3
> Unit 0 Disk COMPAQ HB00931931 03F168224A01GAGSPCQ3F1
> 09RI9904200012259H7007
> E32284 Q59H6952B09E31916 1999
>ok
>
>
>After I swap the disks around, using the same machine, the Compaq one
>can no longer be seen.
>
>ok probe-scsi
>Target 3
> Unit 0 Disk SEAGATE ST39103LC 0001LS482885
> Copyright (c) 1999 Seagate
> All rights reserved
>ok
>
>
>That behaviour is repeatable.

Is one of these hardwired to SCSI Target 3, and the other one is picking
it up from the slot/position. Like IDE in cable select mode.

So one would be switching 1 and 3, and the other stuck on 3 and 3,
and colliding in one of the configurations.

Is there a way to force it to target 2 ??


>
>But when I move the disks to another SS20, both can be seen in any
>position, but I'm pretty sure they had the same problem in yet another
>SS20.
>
>
>> I have a couple of spare SS20 backplane & cable assemblies here
>> (Toronto, Canada), perhaps you could try one if the logistics aren't too
>> complicated.
>
>Thanks, but I am in the UK, so a long way from you, but in any case I
>have five SS20's here.
>
>> Triffid
>
>
>It all seems very odd. But I have had problems with other Compaq disks
>in SS20's before, so this is not a total surprise to m<
>