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Using ST-225 HD in CBM D9090 Drive


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  Using ST-225 HD in CBM D9090 Drive by Bill Degnan - 09/30/2006 09:59
More on the Commdore D9090 hard drive with pics:

I have given up trying to find a 6-head Tandon 603s, and I decided to use a 4-head ST-225 because they are easier to find. I used a B-128 to format the drive.

1) On the controller (top) I snipped J14 jumper to make the D9090 think it was a D9060. This modification is necessary because the D9090 controller is set to use a 6-head drive. Clipping J14 converts the controller into a de-facto D9060 which expects a 4 head drive. The D9060 came with Tandon 602s.

2) I removed the Tandon 603s hard drive that originally came with the drive, reassembled w/o cover.

3) ran a quick test to be sure that the drive was put back together safely:

> ?ds$ [enter]

73, CBM DOS 3.0.0 etc

4) I used the following command:

>header "degnan",d0,i01 [enter]

Are you sure? y [enter]

5) Both drive lights came on solid green, no visible flashing, and I was no longer able to type at the computer.

6) I looked inside the drive at the light of the ST-225, also solid

7) I listened closely, heard nothing other than the drive spinning. A stethoscope would have been useful here.

8) After about 15 minutes I noticed that the drive light would flick once every 10-20 seconds, and the drive would simultaneously click very softly.

9) Left room, had dinner

10) Came back about ~45 minutes later, the drive had returned control to the computer.

11) ran a DIRECTORY command

19441 blocks free

12) The Tandon 603S sits "higher" than the ST-225. As a result I need to use taller risers on the back two posts, and for the front two posts I need slightly taller again front risers.

..geez I think I went through 10 drives before I found a working drive (by first testing in an IBM XT). Hopefully this will help people in the future with the same project. There isn't really anywhere on the web that clearly explains the process of replacing the Tandon 603s brick with the ST-225.

  9090 salvage with an ST225 this week-end by herve warin - 04/13/2009 19:07

I've bought a 9090 on eBay in 2004 or so. It arrived at home slightly shocked and I've never been able to make it run. The most I've obtained was 73, CBM DOS 3.0.

I've tried numerous things without any succes and left it for a future action as all MFM hard disk I had kept (and serioussely checked before having been stored in the 90es) were not working at all and I still haven't any PC-XT class copmputer to check a low level format and so on.

Chance came to me saturday, when a guy at phone told me to come and get it's 4032, 2031 and other stuff. Everything was in perfect condition so I decided me to have a look once again to the D9090 as I had a "brand new" PET configuration operationnal.

What I saw on the D9090 was :
- 73 CBM DOS message ==> DOS board probably OK
- Tandon 603 not spinning up ==> HHD failed ? Or power supply ?

- I had a look around and found an ST225, as new, removed from a MegaFile30 or so.

- I've put the ST225 in place of the Tandon 603, changed J14 to J13 then retried once again. The ST225 spinned up, seeked 0 track and seemed ok.
- I had the 73 error, then on any command sent to the 9090, the answer was 74 - Drive not ready. I was at the same point than years ago : HDD or SASI.

AND I had an idea when I had a look at the original control cable that was with the ST225 - Crossed wires ! A look at comodore's control cable - straight - Bingo

A search on the net and I had the user manual for the ST225 : 1 jumper to move to the left. Did it, retried - and it started formating - Nice double solid green LEDs !

Few minutes later - 11 flashes cycling - Another search on the net and I've found that 11 flashes on a 9090 when formating means "too many errors" - A bad hard disk once again ? Too bad ! Tried again and again with same issue.

And then, the second idea found in the ST225 documentation : Physical disk orientation ! I had put the ST225 in the same place the Tandon was - this means upside down - and seagate is very clear on this (and everyone knows that :) the HDD have to be upside up !).

Once each board was reoriented, the HDD on it's side, the formating continued, passing a track about each 8 seconds, then formating finished perfectly with 194xx blocks like a charm.

===> I am now a very happy Commodore entousiast owning a working D9090 that I've waited for 5 years !
===> I am asking me few questions about D9090 and I didn't found any answers on the net :

- How many D9090 or D9060 still working ?
- How many where made ? (mine has a serial number about 57xx)
- Does it exists a sort of "Test/Demo" for it ?
- Does it exists a user manual (not the technical manual I've found somewhere, a simple user manual) ?
- Does it exists some details on the SASI board ?
- Would it be possible to add a second MFM HDD on it ?
- Would it be possible to replace the SASI board and the MFM DSS with an OLD SCSI 1 HDD ?

Any answer welcome

Regards - Hervé

  CBM D9090 by Bill Degnan - 04/13/2009 19:59
I doubt there are more than 10 of these that work, I only know of one or two other than mine and yours. Congratulations for sticking with it. I hope my web site helped,

By snipping the jumpers you've effectively made a D9090 into a D9060 (5 MB). I have never once seen a Tandon 603S drive for sale on Ebay, and the ST225 seems to be only available replacement. These are also hard to find in working order. I have an entire box full of dead ST225s. I have learned that when you install an ST225, don't put on the cover and don't tighten the controller card tightly before you test. Also remember to run the drive for at least 10 minutes before you do anything.

There is a diagnostic for the hard drive, and a user manual. I can sell you an original copy of the manual if interested. I have a copy of the diagnostic, but it was never sold, it's the repair person's copy.

  Working D9090 owner's club .... by herve warin - 04/14/2009 08:05
Hi, Bill

I can't belive that the club of D9090 working owners can be so select ! Mine was dead for 5 years and took no more than 2 hours for it's resurection ...

I can assure that your web site helped me; not directly at the moment, but at least assuring me that it was possible ...

As far as I can recall, there had not been an enormous battle for it on eBay when I bought it ... and it made twice the travel from Germany to France as FedEx was incapable to put me a phone call to tell me it arrived !

Well, regarding ST225, as it was also fitted in MegaFile's Atari, I've salvaged quite a lot of them at the time, by just removing electronic board and turning by hand the plate engine that was stucked.

Regarding the electronics of the 9090 with a ST225, I simply added 3 metal spacers (didn't found a fourth yet) usualy used for "modern" PCs mainboards and the result is absolutelyu perfect.

That's very kind to you for the original copy of the user manual but I'm not so interested in "paper" collection ... it's the contents of the manual that would be of interest to me - Don't know it someone already scanned it for future generations.

I'll try to salvage the Tandon drive as I'm not sure if its fully dead or if something can be made for it - I do belive that something can be done (and may be find interesting stuff on it ?).

Regards - Hervé

PS : I'll try to run the test/demo program that searches for bad tracks & sectors ... I'll see if it works !



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