BlueSCSI to the Rescue

Using BlueSCSI to Rescue Vintage Macs from SCSI Hard Drive failures

I have several Vintage Macintoshes that use internal SCSI hard drives and also have DB25 SCSI ports: a Mac Plus, a Macintosh TV, a Color Classic II, a Performa 6300CD, and a PowerMac 5400/120.

I have had SCSI internal drives fail before.  After 30+ years they are prone to fail for a variety of reasons. Most well known is that Quantum drives commonly used in vintage Macs have two posts covered in rubber that after decades turn to sticky goo and lock the drive head. DIY attempts to repair these drives are iffy at best because they can be easily damaged further in the process of trying to repair them.  I have also found that the case screws which need to be removed are often almost impossible to get off with a screwdriver, even after applying WD-40. After two recent drive failures in a short span of time I purchased plastic inserts which may resolve the stuck head issue but as of yet been unable to open a drive to test them.

SD based alternatives have been available for a while so I decided to consider that rather than continue to depend upon 30+ year old SCSI drives.

I decided to try BlueSCSI. BlueSCSI is a very affordable micro-SD solution that works on most Macs that have a SCSI port. They can be built from a kit if you have the tools and skills, or, as I did, purchased from a approved builder.

The BlueSCSI is designed to replace an internal hard drive, so to allow the flexibility of plugging it into a DB25 port I also purchased the OverEasy II Adapter. I prefer not to have to open my vintage computer to get to the SD card.

Using BlueSCSI with a Color Classic II

I purchased my first BlueSCSI and OverEasy II Adapter after the recent failure of my Color Classic II internal drive. Plugging into the SCSI port is doable but would block a serial port. Because the CCII lacks an internal CD-ROM drive I would also like to use an external CD-ROM drive and use the SCSI port for that.  I also tested using an Iomega SCSI Zip drive connected to the port and the BlueSCSI+OverEasy II connected to that.

The Color Classic II is running MacOS 7.1 with System Update 3.0

I was able to chain the BlueSCSI+OverEasy II to the Zip drive to the SCSI port and use both the BlueSCSI to boot off of and access the Zip drive.

I was able to connect the BlueSCSI+OverEasy II using a CN50M-DB2F adapter to the CD-ROM drive Centronics port while connecting the CD-ROM drive to the Mac SCSI port. This allowed both booting and accessing the CD-ROM drive.

I was unfortunately not able to use all three devices at the same time. This would cause Bus errors even though all devices have unique SCSI IDs and termination was set correctly on only the end of the chain. I don't know if having the internal hard drive still connected even though it fails might be causing this issue.

Because the CD-ROM drive is more useful to me than the Iomega Zip drive, I decided to go with connecting the BlueSCSI+OverEasy II to the CD-ROM drive, and the CD-ROM drive to the Mac SCSI port.

Using BlueSCSI with a Macintosh TV

Having had to replace the Macintosh TV internal SCSI drive in the past and dreading drive failure on booting, I would like the boot drive to be a reliable solution and the internal drive used only as a secondary data drive.  I do not need to chain any SCSI devices on the port so the BlueSCSI connected via OverEasy II adapter to the port makes sense.

The SCSI port on the Macintosh TV is close to the serial printer port and it would be blocked if the OverEasy II is plugged directly into the SCSI port.  I considered two options that would prevent serial port blockage: using a short SCSI cable so that the BlueSCSI could be in front of the computer and easy to access; or using a right angle DB25 adapter that would allow the BlueSCSI to be plugged in vertically. A third option I did not test but might also work would be to use a MM DB25 adapter and FF DB25 adapter to extend the port out.

Using a short SCSI cable turned out to be problematic. First, getting one is a problem. The DB25 short cables you can buy now are usually parallel cables, not SCSI cables, and the one I purchased did not work at all. The short cables that come with an Iomega Zip SCSI drive seem like they should work work except they have two male ends. So I purchased a set of 5 FF DB25 adapters. Though using the combination of a Zip SCSI cable, a FF DB25 adapter, and the BlueSCSI+OverEasy II, I had inconsistent results.  Usually the drive would not mount and show on the SCSI bus despite the LED light on the BlueSCSI being lit up. It is possible that the FF adapter I purchased was faulty, but I purchased 5 and it doesn't stand to reason that all of them are faulty. It occurred to me that termination power may not being passed through the Zip drive cable, but providing 5v power to the BlueSCI directly using its micro-USB port did not improve the inconsistent results. So I abandoned this approach.

I did have success with the second option: using a right angle DB25 adapter and BlueSCSI+OverEasy II adapter. This allowed the BlueSCSI to be set up vertically and did not block the serial port.

Using BlueSCSI with a Macintosh Plus

For the Macintosh Plus I had several options. The Macintosh Plus does not have an internal hard drive, but I have a large noisy non-Apple functional hard drive in a case that can chain a SCSI device as well as a second smaller silent non-Apple functional case that lacks a port for chaining that I could put the BlueSCSI inside and connect to power using a Molex to Berg adapter with no need for the OverEasy II. I could also plug the BlueSCSI+OverEasy II into the Mac Plus SCSI port, though I would also need to use a right angle DB25 adapter to prevent blocking the serial printer port. Using the port directly would also require adding a power source for termination since, unlike later Macs, the Mac Plus SCSI port does not provide power for termination, so a 5V charger and micro-USB cable would also be needed.

The first option I tested was connecting the BlueSCSI+OverEasy II to the large noisy but period correct external hard drive via a CN50M-DB2F adapter. This proved successful with both drives mounting consistently. Functional but very loud. And considering the small amount of software, two hard drives are not really needed. For what it is worth this did look period correct though.

The second option I tested was connecting the BlueSCSI+OverEasy II to the Mac SCSI port using a right angle DB25 adapter. Because the Mac SCSI port does not provide termination power I also connected a 5v charger into the BlueSCSI via its micro-USB port. This proved successful and completely silent. And because the Mac Plus and the 5v charger are plugged into the same power strip, the BlueSCSI will always have power when the Mac Plus is turned on.

The third option, and the one I decided to use, was to mount the BlueSCSI inside a small external case connected to the Mac SCSI port with a standard DB25 Male to Centronics 50 Male SCSI cable. The case has its own external power and to connect that to the BlueSCSI for termination power I used a Molex to Berg adapter. One advantage of this solution is that the BlueSCSI is mounted inside a case offering it some protection. This particular case has a plastic lid, so I still have easy access to the BlueSCSI in case I want to swap out or backup its micro-SD.