Suggestions why SCSI 80 drive w/ SCSI2 (50) adapter will not spin up ?

[Paul Berger]

On 2017-03-20 11:50 PM, Pete Lancashire via cctalk wrote:
> Host is a HP 9000/382
>
> Copied the orig drive using a linux box, adaptec 2940N and good old dd
>
> Then swapped drives, a unused 9 GB 80 pin with a Chinese 80 to 50
> adapter.
>
> Did have to issue a spin up command and then copied the data to this drive
> again with dd.
>
> Powered all off, added a motor start jumper to the adapter and put it on the
> 9000/382. Motor will not start, added a jumper right on the drive, no spin.
>
> so .. any ideas what I'm doing wrong, or just try a different drive ?
>
> -pete
Well if the drive has an 80 pin SCA interface there is a chance that it 
is a LVD drive, which normally would be ok since LVD devices are obliged 
by the SCSI spec to be able to operate in SE mode as well, but the 
problem may be you 80 to 50 convertor.  I have encounter some that are 
not correctly wired and as a result do not always work.  LVD SCSI 
devices monitor a line call DIFFSENSE which is pin 46 on the SCA 
connector for SE operation this pin needs to be grounded, it is also 
possible that the drive itself has an option jumper to force SE mode if 
it is an LVD device.  It would help if you mentioned what the model of 
the drive in question is.

Paul.