Re: D9060 Help Needed

On 11/30/09, Jim Brain <brain@jbrain.com> wrote:
> I've just acquired a CBM D9060 HDD.

Nice.

> After making temporary repairs, 5V is once again going to all boards.
>
> Bootup ?ds$ gives 73, CBM DOS 3.0...., and any subsequent command gives
> "74, DRIVE NOT READY..."
>
> I noticed the lower LED was wired backward, and there is a possibility
> the cables to the HDD are backwards.  Anyone have pics they can share or
> a way to determine correct orientation?
>
> I noticed this note about the cables:
>
> http://www.vintagecomputer.net/browse_thread.cfm?id=35

Interesting thread.  I disagree with Bill Degnan - there have to be
more than 10 of these left in the world - I have two or three myself -
I picked them up back in the late 1980s when nobody wanted them
anymore, and they weren't expensive.  Before we understood enough
about the low-level drive requirements (more on that later), I paid a
drive-refurbishing company to re-do one of my TM602S drives (it had a
bad track-zero sensor).  I started with a pair of bare boards and
ended up refurbishing several broken complete units.

> Any other ideas to try?

Given that you don't know about the state of the Tandon drive, I'd
grab an ST225 or ST251 and drop that in there (checking the drive
select jumpers and cable orientation, of course). One of the things
that has been learned in the past 20 years is that the specific drive
parameters (reduced write current, write precomp) match adequately for
the first 150 cylinders between a TM602S and ST225 and a TM603S and
ST251.

Be sure to check the state of the J13/J14 jumper - it goes in D9060
mode for a 4-head drive and D9090 mode for a 6-head drive (or you can
just leave it at 4 heads for either drive).  One unit I "repaired" had
a 4-head drive but was set for 6 heads.  As expected, the low-level
format was unsuccessful until I matched up the board setting with the
capabilities of the hardware.

You probably already know this, but in case someone else finds this
thread on an archive later, dropping in a "20MB" or "40MB" drive does
not increase the capacity of your D9060/D9090 - you still only get 5MB
or 7.5MB, but the Seagate mechanisms are *much* easier to find than
original-era 5MB and 7.5MB mechs from any vendor.  Yes, you are
"wasting" 75% of the drive, but at least it works as well as it did
when it was new.  I believe you can hack the ROMs to boost the
filesystem up to the max allowable (16MB?), but I have not done that
myself.

Once the new drive is in place, try a 'header' command ("N0:") to get
the D9060 to low-level-format the Seagate mechanism.  If that works,
you can either use that drive or replace the original drive to see if
it works and if you can extract any original content.

You should also check the ROMs on your boards against the versions
dumped on zimmers.net -
http://www.zimmers.net/anonftp/pub/cbm/firmware/drives/old/9090/index.html

I have an old CBM document that mentions that the newer version of the
ROMs takes substantially longer than the older version (like 2 hrs vs
45 minutes), so I thought I should mention it if you get impatient.

> Anyone have a working D9060 that might want to try out the boards?

I do, but I think there's still things you can try on your own before
you send things out.

Feel free to ask more questions as you work through this, or if you
think you've gone far enough, send me the boards to test.  They weigh
lots less than the drive, so they won't be expensive to ship.

-ethan

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