• Please review our updated Terms and Rules here

Later U320 SCSI SCA 80 pin Drives and Adapters Use

Zippy Zapp

Experienced Member
Dec 13, 2014
Hi All,

Recently I have been experimenting with SCSI 10k drives as replacements for older dead original Mac SCSI drives with some of my older Power Macintosh systems (7500, 8100, etc...) I know this is nothing new but information that I have found on other forums is somewhat spread out and not a ton of information on uses, which drives, adapters etc. I am going to document my tests and hopefully with the combined knowledge around here information can be added to the thread so people looking to replace their drives will have a thread to learn and discuss.

Drives I have tried so far:

Seagate Cheetah ST39102LC Hard Drive 9.1GB

This drive works perfectly with adapter. So far I have tested it on a Power Macintosh 7500/100 with Mac OS 8.0 CD. Drive Setup saw the drive and initialized it with no problem. Does not require a 3rd party formatter or patched drive setup version. I have tried it with both of the adapters listed below and they both worked with it.

Configuring the Drive
For this drive it comes default with no jumpers installed which equates to SCSI ID 0.
There is a jumper block to configure things like Force Single-Ended mode, Delay Motor Start, Enable Remote Motor Start, Write Protect, Parity disable. I used no jumpers so everything was the default.

Seagate Maxtor 8j073j0 72GB 73GB 10K SCA U320 Ultra 320 SCSI Hard Disk Drive

This is a NOS drive and I configured it with the defaults too. Which basically means, like the Seagate, no jumpers needed. Drive Setup recognizes the drive but will not initialize it as it is unsupported. I assume here you need to use a 3rd party formatter or a patched version of drive setup that supports 3rd party Non-Apple OEM drives. I am going to run more tests on this drive.

I have a couple of other drives I am going to test including a 2.5" SCSI server drive from Seagate and a 18GB Seagate drive.

Configuring the Adapter
The adapters I use have jumper blocks for configuring the ID, Motor Start, etc. If you want to configure to a different ID you will configure it on the adapter not on the drive. I chose to leave it at 0 for my tests because I wanted to create a bootable system. I left all jumpers open.

I have used the following adapters:

SCA 80F/IDC 50M Hard Drive Adapter with Active Termination-SCSI U320,U160,LVD,SE

SCA 80 Pin to 68 Pin 50 Pin Ultra SCSI II/III Adapter Converter SPC-2603

I experienced no difference in functionality between the terminated adapter and the regular adapter. I have not used SCSI probe to see what it is reporting but I am not sure if it matters which adapter to use. See questions below. If I recall, later drives, such as these, were auto terminating.

Questions remain as to which Macs these will work with. I have tried it so far with 2 different Macs with the same result, they work. I have some older Macs one is an LC III but I am not certain it will work with this Mac. I know it would most likely need to be partitioned in 2GB chunks or less. My LC III still has the original 160MB drive in it and I have not tried to see if the new drives, which will fit by themselves will actually fit in the limited HD space with the adapter installed. If everything fits in the case I don't see any reason why they won't work though.

Another question is whether or not a terminating adapter is required? If someone has a definitive answer, then that is what this thread is for so please add your knowledge as I am not a SCSI expert.

So far this looks to be a good solution for replacing ailing original SCSI drives. These drives, were designed for long life. Their failure rating is much lower, IE MTBF of 1,500,000 hours vs, 100,000 - 500,000 for your usual consumer SCSI drive. That said these are 10k RPM drives and they can be a bit louder then regular drives. Compared to some of the older Mac drives though, these seem to be not so much louder or even quieter in some cases.

Heat generation is another concern. These drives can get hotter then original drives and that should be a consideration. The instruction manual available for these drives does have information on cooling and such.

I realize that some are moving to the SCSI2SD adapter that seems like it is becoming popular. This devices are great for your older slower systems but they are not too fast and can't keep up with the SCSI2 rates that are used by the Power Macintosh line.

For drive types that are compatible I know that many SCA 68 and SCA 80 pin drives are compatible withe the appropriate adapter. An SCA 80 adapter should always have a molex for power as there is no separate power plug on an SCA 80 drive, it is built into the connector. You will also need to make sure that the drive supports Single-Ended mode (SE) and is backwards compatible back to SCSI 1. Many of the Seagate drives I have researched are, especially those ending in LC.

TODO - I need to add the versions of drive setup and drive software that I am using in the tests. I will edit the post as I continue the tests. I will be adding to and editing this post for other tests too.

I will also add drives you find compatible in the post under a section for compatibility.

I hope you find something useful here and please add your own knowledge/comments so this can be a good resource for people looking to replace their aging SCSI drives.
I had some 10 gig IBM's that I got SCA80 adapters for and they worked great in my 9600 using the patched drive setup
dont know what the exact model was cause that was a few years ago and the machine has since found a new home
Thanks for the info, I'll add them to the list. I have two additional drives coming in so I will test those and post too.
I think to keep things standardized maybe we could post the Drive Brand, Model Number, Size, OS Version used, Drive Setup Version and if you needed to partition it down to work with an older system. At least that should be good for classic. OSX isn't picky about what drives you use so doesn't really apply in the context of classic.

I'm new here and have a persistent SCSI-problem with my G5 quadcore PowerMac running Tiger. It has an ATTO dual-channel UltraWide PCIe card which I want to use with my good old MicroTek Scanmaker III.

I've been using the scanner with an Adaptec PCI card (cable was a HD50 to Centronics) in my older G4 running Tiger using VueScan without problems. But I can't get it to work with the ATTO-card.

Fist I tried the internal HD68 connector via a SCSI adapter to 50-pins flatcable to HD50 female. That didn't work. Then I bought a VHDCI to Centronics cable on eBay which doesn't work either.

Has anybody any suggestions how to get the scanner to work again. It has a nice transparency module which I want to keep using. Thank you.

Best regards, Jörg.
I've used various 68 pin SCSI drives in my 68k Macs (LC III, Performa 600 and IIsi when I had one) with the only issue being space. The LC III doesn't have enough room behind the drive for the 50 to 68 pin SCSI adapter, so the case has to stay off. Alternatively, the drives can be mounted in an external enclosure and plugged into the back of the machine.

I have a few SCA80 SCSI drives, but I can't justify the expense of getting an adapter for them, especially because they're only 9 GB drives. Most of my 68 pin SCSI drives are 18 or 36 GB.
II have a few SCA80 SCSI drives, but I can't justify the expense of getting an adapter for them, especially because they're only 9 GB drives.

My favorite solution is external drive boxes: no space issues, power supply included, and they don't overheat compact Macs or small Sun systems. My personal favorite disk enclosure is the Sun "UniDisk" box, which can be found with hard disks, CD-ROM, tape, etc. All of the disk version boxes I have are SCA and include auto-termination for both 8- and 16-bit modes. They'll even terminate only the upper bits if the next device in the chain is 8-bit only and has a terminator.