Profile Hard Drive: Info, Maintenance, and Formatting
by Patrick Schaefer (March, 2000)

supplied by Dakin Williams



Good news first: everything in a Profile is serviceable. The drive
mechanism is a regular Seagate ST506/412 (IBM AT drive), the electronic
components can be checked by swapping into a working drive. First the
boards, then single chips.


Maintenance

Although ST506 mechanisms are, naturally, rather noisy, you can probably
reduce noise on a Profile drive which has not been regularly serviced.

You can disassemble the profile, remove any dust located under the analog
pcb and put a drop of oil on the tip of the copper spring that touches 
the spindle motor axis. Do not rotate the step motor and do not oil 
anything else! And of course do not open the drive unit itself.

Reassemble the profile but do not put the cover on it. Connect it to the
power line, switch it on and wait. After 18 seconds the stepper motor 
will move from its park position to track 77, then to track 0.

After that, a surface scan of the disk is performed. You will see the 
step motor rotating slowly while the heads travel from track to track.
Sometimes the heads jump to track 77, then the scan continues. This
means a bad sector has been found. The drive does not access this
sector, it uses a spare sector instead. There are located on track 77,
32 are available.

Now watch the surface scan and count the number of movements towards the
spare track. A new drive uses 0..2 spares, 3..5 is means fine condition.
With more than 10 spare sectors used you should look for someone with
low-level formatting tools.

The main problem with these older drives is that information stored on 
magnetic disks fades after several years. The data sectors are rewritten
every time you store something on the disk. But the address field 
headers are not. They were written in the factory and never changed 
since then. If a couple of header bytes fail the drive cannot locate the
associated sectors and it assumes they are bad. So you will get a lot of
bad sectors reported, however your disk surface is okay. Low-level 
formatting rewrites everything on the disk.


Low-level Formatting

Formatting a Profile requires an Apple ///, some software and a special
formatter chip that replaces the Z8 chip on the logic board. With the
formatter chip Profile understands a new set of commands, then you can
format the drive, do a surface scan and initialize the spare table.These
formatting tools are very difficult to obtain, because there are still
some people eaning money with them (the 'certified Apple technician'). 
In the US you can contact Steven N. Hirsch [shirsch@adelphia.net], 
perhaps he will do the formatting for you.

Unfortunately Profile and Widget are the only drives that could be used
with a Lisa 2 without any restrictions. SCSI drives are available from
Sun Remarketing, but they require a driver to be loaded first, and this
means you have to start up from diskette. Thererfore it is necessary to
maintain these old machines as long as possible.

Some time ago I have started disassembling the Z8 code and drawing a
schematic diagram of the loagic board, but this hasn't been finished yet.
I thought about designing a Widget emulator based on an IDE drive.

I am still looking for some information about formatting Widget-10 drives


Regards,
Patrick