Jump to content

Recommended Posts

I have a Macintosh HD20 that came with my Plus, and it doesn't seem like the drive itself has stood the test of time.

 

When I boot up my Plus with the drive turned on it will attempt to boot from it, and then fail.

 

I eventually gave up on it, used my Centris to burn some System 6.3 images and boot the Plus that way (which took like 10 times of inserting the Utilities disk, not entirely sure wth was causing that :O )

 

Once booted with the HD20 connected and turned on, System 6.3 recognized it, and immediately tried to mount it. It failed, and wanted me to initialize. At first I canceled, because a label that came with it claimed it had the OS and several nice apps already on the drive. I attempted to run Disk First Aid (I think) to try and solve the problem, thinking all this time in storage had simply caused some bad sectors.

 

Turns out that it couldn't fix whatever error was happening, so I just decided to initialize it and be done with it. This, unfortunately, also failed miserably, it won't initialize.

 

The controller card does seem to be fully functional though, as it does obviously spend time trying to read the disk. I thought I felt vibrations on the disk itself when I tested it earlier, so I don't know what to think.

 

Does anyone know of another program that may be able to get this drive working?

 

If the drive is indeed dead, is there any place that still services these hard drives, or would I be doomed to trying to find one on eBay D:

 

-Academician

Link to post
Share on other sites
  • Replies 77
  • Created
  • Last Reply

Top Posters In This Topic

The best resource I know of is http://www.mandrake.demon.co.uk/Apple/hd20.html

 

The site refers to a couple of utilities that might help you revive a balky HD20. I wish you success, because those drives are getting rarer all the time. My old trusty one has developed arthritis in its old age. I have to give it a little kick to get it going. Only a matter of time until that won't work...

Link to post
Share on other sites

I did find the HD20 Startup Disk and burned a copy. The drive failed the test within seconds and it doesn't seem to be format-able either :'(

 

Thanks for the link though, it sure helped me put another nail in this things coffin so I don't have to worry about it, for a while anyway.

 

-Academician

Link to post
Share on other sites

Has anyone ever developed/discovered a replacement mechanism for this drive? I find it very hard to believe that Apple has not only a custom controller board but also a custom drive mechanism. There should be some way to fit it up with a standard RLL or MFM drive...

Link to post
Share on other sites
I find it very hard to believe that Apple has not only a custom controller board but also a custom drive mechanism. There should be some way to fit it up with a standard RLL or MFM drive...

 

I agree. I've been planning to open up mine "one of these days" and see what the mechanism is. As do you, I assume that the mechanism itself is a standard ST-412/506 type of drive. Still have a few of those kicking around in a box somewhere...

 

Academician -- if you happen to have a camera handy, could you post a few pics of the drive mechanism itself? Enquiring minds want to know...

Link to post
Share on other sites

Tom, there's no need to open your HD20. I posted a full set of photos of my HD20 here.

 

It's a Rodime drive mechanism. And no, I am not aware of what modern hard disk drive mechanism (if any) would be drop-in compatible for the Rodime.

 

And if you've not already seen my HyperDrive 20 photos on Flickr, check those out too. The drive used in the HyperDrive setup was made by a company even less well known than Rodime: Microcomputer Memories Inc. I Googled that name, but not much comes up.

Link to post
Share on other sites
I find it very hard to believe that Apple has not only a custom controller board but also a custom drive mechanism. There should be some way to fit it up with a standard RLL or MFM drive...

 

I agree. I've been planning to open up mine "one of these days" and see what the mechanism is. As do you, I assume that the mechanism itself is a standard ST-412/506 type of drive. Still have a few of those kicking around in a box somewhere...

 

You would think. So did I... But it does not appear to be any kind of standard interface. It is possible that the wires there map to a 412/506 with some of the power or grounds removed or something, but it would be a lot of work to trace the custom controller card to the point where one could interpret the pinout of the hard drive. The connector certainly seems to be one not used elsewhere on hard drives.

Link to post
Share on other sites

Is your drive a clunker? One of my PB 150's had a clunking hard drive, which is usually a sign of a dead drive and I figured since it was already dead I had nothing to lose by opening it up and taking a look inside. Imagine my surprise when I put it back together and reinstalled it and it came back to life! I have a Western Digital drive from a beige G3 that is a clunker that I want to open up, but I don't have the right screwdriver to get it open. I'm going to see if I can eventually get that one working again if I can borrow the right tool from someone.

Link to post
Share on other sites

 

You would think. So did I... But it does not appear to be any kind of standard interface. It is possible that the wires there map to a 412/506 with some of the power or grounds removed or something, but it would be a lot of work to trace the custom controller card to the point where one could interpret the pinout of the hard drive. The connector certainly seems to be one not used elsewhere on hard drives.

 

That's too bad, indeed. That makes resurrection of these increasingly rare drives that much less likely.

Link to post
Share on other sites

In 1984/85, Apple went to market to find an OEM to supply hard disks that would become the HD20 unit. Assume that Rodime offered a good deal for a non-standard drive, with continuity of supply, and that Apple believed that it would be cheap to build a floppy port bridge board for the offered drive. And that is what we have.

 

Possibly Rodime used the same drive mechanism in other offerings. I always suggest that you crack open an early compact Mac or "SCSI" drive, just to see what is inside. Rodime drives are also found in old MIDI kit too, but that kit is as scarce as an HD20.

Link to post
Share on other sites
  • 4 weeks later...

From JDW's pics I gather that the drive proper in the HD20 is a 3.5-in mechanism, where I might otherwise have supposed that it is a 5.25-in. The drive in his pic. closely parallels a (later?) Rodime that I have, which differs in Build Level (7A) and Option No (3), and also in logic board supply current (1.25A), which may be explained by its being patently for SCSI use. My memory is that it came from an SE/30.

 

Just on three years ago I received my first Apple 20SC external SCSI drive M2604, with Apple logo but no model designation (as opposed to the M2603 cases marked 20SC, 40SC, 80SC and so on). It contained a Seagate 5.25-in ST225N drive, a monster that was responsible for my paying four times the drive price in shipping cost to get it here. It may be a reasonable guess that this assembly was produced as an external drive for the Plus. Although the Plus, and the IIci also, have ROMs that can talk to an HD20, it is possible that the HD20 was quickly supplanted soon after SCSI was first built into Macs, even though Rodime continued to supply drives with SCSI controllers as internal HDDs.

 

de

Link to post
Share on other sites

Just wanted to weigh in since I didn't see this mentioned. It has always been my understanding that the Rodime drive was indeed fitted with a proprietary controller. This Apple Tech article indicates one conversion method I've heard of which seems to support that the drive itself could not be converted to SCSI, but the interface logicboard could be replaced to interpret for SCSI (or maybe I'm reading too much into it). equill's comment is equally enlightening concerning the size of the drive itself. Clearly the case was designed to accommodate a 5.25" drive. When I first cracked my HD-20 case I was in awe at all the wasted space. Indeed if you look at JDW's pictures you'll see what I mean. From an aesthetic perspective I always hated the bulge on the back to accommodate the fan. This could be the result of a last minute change from the 5.25 they were planning to, as Charlieman suggests, a deal with Rodime to provide the smaller 3.5" drive for eventual inclusion in other Macs. With the 3.5" drive the fan could have easily been included within the footprint of the Mac.

 

As for a dead unit, assuming it's not the drive itself, you could always hold out for one of these SCSI conversion kits mentioned in the Apple article, but that may be just as rare as a replacement HD20 drive if that's your problem. Otherwise you could replace the whole shebang with a modern internal SCSI drive. I have thoughts of putting my ZIP 100 in there since it will boot with system 1.0 through 6 (once formatted) and is absolutely silent when not accessing the disk and requires no fan. 100MB is plenty with an old Mac (and significantly more than the HD20). Disk access would have to be through a modified hole in the side vents, but that would be a minor alteration, mostly hidden by the external disk drive, which by the way the ZIP would easily fit inside as well, though requiring more visible cosmetic surgery on an already rare and useful 400K drive enclosure.

 

It could even be used with a 512k and possibly a 128K Mac with 128K ROMs and a Dove MacSnap SCSI card which surfaces on eBay from time-to-time (albeit not cheap!) Seethis Apple article. Using something like MacServe you could even format an MFS volume partition comprising almost the entire volume and still avoid switching to HFS.

 

Even if I had a working HD20, I'm not sure I would use it except for storage (the main reason I want a viable 800K MFS drive solution) to be accessed at a minimum. It is a noisy beast that must have driven Steve Jobs out of his mind ... oh yeah, he left Apple the month it was released! LOL

Edited by Guest
Link to post
Share on other sites
From an aesthetic perspective I always hated the bulge on the back to accommodate the fan.

A kindred spirit. Despite it being out of view (in the back, as opposed to the front), I know "the fan bulge" is there, and for some reason it bothers me.

 

The Japanese contend that such feelings are characterstic of those, like me, who have Type-A blood. :b&w:

Link to post
Share on other sites
Just wanted to weigh in since I didn't see this mentioned. It has always been my understanding that the Rodime drive was indeed fitted with a proprietary controller. This Apple Tech article indicates one conversion method I've heard of which seems to support that the drive itself could not be converted to SCSI, but the interface logicboard could be replaced to interpret for SCSI (or maybe I'm reading too much into it).

 

What I find particularly interesting about this article, is that it implies that, at one time, someone at PCPC understood the interface to the HD20 drive--either that or this adapter sits between the floppy connector and the host computer, but I do not think that is the case. I think it is a replacement interface board, from the way the article is worded.

 

So, we must now find someone who did design work for PCPC...

Link to post
Share on other sites
I think it is a replacement interface board, from the way the article is worded.

 

I saw (but did not bid on) one of these interface kits on eBay not long ago. The listing appears to have dropped off the completed search.

 

From what I recall, it appeared to replace the logic board in a HD20 to provide a SCSI interface to the HD20 drive mechanism.

 

Regards,

 

Macdownunder

Link to post
Share on other sites

While it is perfectly conceivable that Rodime might have used different platter separations and different head constructions in the same motor-and-platter diecast box as they later used for SCSI drives, providing a different logic board also for each style of storage, it seems a little painful. JDW's pics of the Rodime in his HD20, and my SCSI drive, differ only in 'Option Number' (read construction/storage mode?) and Build Level (que?), nonetheless.

 

I have to presume that Rodime never 'filed' its secrets on the Web?

 

de

Link to post
Share on other sites

That's how I read the Apple article, too. While I am the last person to discuss technical matters of this nature, if equill's drive is physically identical to the HD20 drive mechanism, I would suggest that the circuit board interface on the drive is the difference and is designed to interface with Apple's HD20 digital board which is sending very different signals than a SCSI interface. I suspect any conversion kit not only provided access to the Mac's's SCSI bus but also translated those signals to the proprietary hard drive controller. So theoretically you could just trade disk controllers for a native SCSI and be all set to plug into a SCSI interface. However, that doesn't really get you any closer to converting the HD20 to SCSI without a SCSI logic board. In other words, strip the guts out of the HD20 reusing only the hard disk and power supply but replacing all logic circuitry. In which case why even keep the drive itself? And the power supply would have to be adjusted to the needs of the new mechanism.

Link to post
Share on other sites

I have found this thread to be quite interesting, especially the technical points hinting at the HD20's interface and protocol. But for myself, I am even more interested in figuring out how to put a bootable flash drive inside my old non-SCSI Mac 512k! Or perhaps substituting a 20MB or 32MB CF flash card for the Rodime drive mechanism in the HD20! Or perhaps swapping the MMi drive mechanism used in the HyperDrive kit with a 20MB CF card! Or for those without either the HD20 or the Hyperdrive, having a CF card and controller kit to be used internally in the Mac 512k and higher (and 128k too, if it has the RAM for it).

 

Flash drive options exist for the ancient Apple II series, as I am sure most of you have seen on EBAY from time to time. So why not the Mac? Makes no sense to me as we Mac collectors should also have an equally interesting number of modern add-ons for our old machines! But then, perhaps this is a topic for another thread.

Link to post
Share on other sites

While it would be a dream, as Dan Knight points out, someone would would need to write drivers for it and I'm afraid anything less than a System 6 would not get much attention.

 

http://lowendmac.com/musings/mm07/0815.html

 

However, I have routinely used IDE to SCSI converters so I could use smaller IDE, cheaper drives on an old SCSI internal bus. Since there are ATA/IDE Flash drive interfaces, this may well be a solution with the right connectors. No special drivers, just connect your flash drive through the IDE to SCSI adapter and plug into your SCSI bus. Depending on the flash drive you may need a special application to format it before you can see it on a very old System (like a ZIP 100 drive), but once formatted it might work on any old System just like my ZIP does.

 

I'm thinking the better approach at this point would be the MacMinitosh running Mini vMac and expand its capabilities ... which I know Paul Pratt is doing. This way you can have the best of both worlds in one case (I think I would mount my MacMini upside down and access the DVD slot through the bottom side vents to modify the case as little as possible.

 

But, you're right this belongs in it's own topic ...

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...