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MAC SE/30: 68 pin UW 160 SCSI drive on internal scsi bus

Posted by: Bendix on 2020-05-11 09:05:30 I have been working on this for quite some time, googled a lot and finally succeeded, so I thought I share my findings. Since the old 50 pin SCSI drives are getting scarce and ebay is full of affordable UW server drives (of ridiculously huge sizes for an old SE/30) I experimented with these and got as far as getting it working in an external case on a 50 pin cable and external active termination. I used a 50 pin to 68 pin male gender changer to connect the drive to the 50 pin cable in the case, jumpered the drive to “SE”, and “NO WIDE” and finally had a stable system. Then I tried to do the same on the internal bus, used a 3 connector 50 pin cable with a terminator at the end but could not get it to work at all, no matter whether I jumpered the drive for supplying term power or not. I even tried a longer flat cable with an adapter for an external 50pin terminator with LED, so that I was positive the bus was terminated. Either the drive was not ready or not visible at all. I finally found an entry in this forum, that advised to use a 50 to 68 pin female gender changer on the logic board and then go from there with a short cut 68 pin flat cable with active termination at the end and that did the trick. So here it is, my SE/30 with a 68 GB Maxtor/Quantum Atlas 10K III UW SCSI. I can connect external devices like disks and CD ROM drives and the SCSI bus seems stable enough.

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