Apple SCSI to IDE adapter board: some basic tests

[Byrd]

Hi,

I recently purchased a SCSI to IDE adapter board off forum member John8520 (great trader BTW), and spent a little time setting it up to work in my "sleeper" Powerbook 540c (167Mhz PPC upgrade, 40MB RAM, Rev C card cage - CF PCMCIA card and wireless card plugged in). It has had a flaky 500MB SCSI drive in there for a while - noisy and in need of a "slap" every now and then to get it to spin up

I believe this is the original Apple part that came with later model Powerbook 540s with 750MB+ hard disks - 2.5" SCSI hard disks didn't come much bigger than 500MB so Apple put IDE disks in there with this adapter. It neatly fits a 9.5mm height IDE hard disk + adapter = perfect size and height for fitting into any 68K Mac with 2.5" SCSI HD.

Installation: the adapter comes with a bracket that is quite fiddly to dismantle and install a new IDE HD onto. You will need some tiny torx bits to unscrew the bracket and some very flat Phillips head screws to mount the drive (there are four holes, but one rubs up against a component on the adapter - just use three), to make the harness solid.

Issues: doesn't work with drives that draw over 500mV; I originally tried an 8GB Toshiba drive that was rated at 5V 700mv; this results in the drive spinning up and down constantly. My only other spare was a 5GB IBM Travelstar (rated at 5V 500mV) which it seemed much happier over. I'd like to have a 20GB drive in there at a later date, and load my 540 up with every concievable app and game I can get to work on it

Performance: the replacement drive is considerably faster than the stock 500MB drive, but it only performs about 10 - 20% faster (going off Norton System Info benchmark). But the new drive is silent, reliable and upgradable!

As John8520 stated, the adapter treats the IDE drive as a normal SCSI device, and if you pull the drive to put into another machine (eg. Powerbook with IDE support), it'll detect and boot off it without any issue.

All in all, this is quite a magical adapter and worth searching around for if you wish to continue regular use of your 68K Powerbook into the future.

JB

 

[H3NRY]

I found one of those in a Duo 280c with a 1GB IBM / Apple ROM drive attached. Since I don't think Apple shipped drives that big in the 280, it must have been an aftermarket upgrade. This drive is rated 5V 500mA also. It works, and I haven't done any further tests to see how big a drive it can handle or anything. Since 68K Macs don't handle iPhoto or iTunes libraries, they don't need huge drives in them. The exception is the Quadra 950 which already has four 9GB IBM SCSI drives in it, and it has long been retired as the digital audio workstation and main archive / server.

 

[Bunsen]

There's a guide to IDE SCSI adapters here

With the Apple 1GB + ADTX PB SCSI drive, you can replace the drive with any 12.5mm or thinner IDE drive. However my ADTX adapters can recognize only a max of ~8GB /
Upsizing an Apple OEM 1GB drive

I formatted an IBM 10GB Travelstar / on an ATA-bus equipped PB, then transfered it to the ADTX adapter plate. At first glance the drive appeared to be all 10 GBs but testing revealed an unholy mess of read-write errors.

Upon re-initializing the drive (using Drive Setup IIRC) it then showed up as an 8.x GB drive with the remaining portion not visible or available for use. Worked fine though, and was quite a bit faster than the old IBM 1 GB dog with which the adapter originally came.

 

[Nathan]

Any chance you guys could get some good photos of the adapter (top, bottom sides, etc)? It'd be interesting to know what chips are on it and what the layout is like.

 

[Bunsen]

Scans to Nubus Mafia specs, perhaps?