Mac 512K with "HyperDrive" add-on: Rare?

[AdamAnt316]

Hello, everyone. I was at an antique radio swapmeet, of all places, when I spotted a Macintosh 512K in its carrying case. It had a badge on the front reading "HyperDrive", which I hadn't seen before. There were no disks in the carrying case, but I figured I'd carry it to the test table to see if it powered up. Imagine my surprise when the expected disk '?' icon turned into a Happy Mac, followed by the HyperDrive splash screen! Turns out that it has an internal hard drive installed, which I'd never seen before in a pre-SE Mac. It apparently has System 1.1 (Finder 5.3) installed across three folders labeled "HyperDrive System Folder 1/2/3", oddly enough. Here are some pictures:

Unfortunately, shortly after I finished taking these photos, I heard a series of crackling and popping noises from inside the case, followed by smoke rising from the ventilation slots! :shock: The unit was turned off at the time, so I'm guessing it was a 'safety capacitor' in one of the power supplies (it apparently uses a separate supply for the internal hard drive). Hopefully, there's enough of it left to read the component value off of, and hopefully I can find a replacement part without too much issue (haven't seen proper X/Y-rated capacitors at my local electronics suppliers, best I can tell). Pyrotechnics aside, I think I did pretty well for $60. :mrgreen:
-Adam

 

[olePigeon]

It's fairly rare. It's a coveted upgrade for many 128k and 512k owners. A working one is pretty rare. Either the HDD dies from stiction or the power supply goes. The reason it's sought after is because you can have a relatively fast mass storage device on 128k or 512k without swapping the ROMs out for a Plus. It was one of the first (if not the first) internal fast mass storage solution for the original Macintosh. The original Macintosh and its successor, the 512k, didn't natively support SCSI or indeed any attached fast storage device, and up until the Hyperdrive was released, the only options for mass storage were serial based. Serial drives by comparison were very, very slow and often still required you to boot off a floppy disk first, then restart to boot off the serial drive.

The Hyperdrive by comparison was really fast as it used SCSI. Not only was it fast, but it was also an internal solution. You didn't have to give up desk real estate for bulky external drives. It was very innovative for its time. If I remember correctly, GCC developed their own SCSI implementation that Apple eventually licensed or purchased for use with the Macintosh Plus.

http://macintoshgarden.org/apps/gcc-hyperdrive-software-drivers

I actually have a boxed Hyperdrive installation kit. I uploaded the software and most of the dealer installation manual (it was missing many pages, but the important pages were there.) It might be useful for troubleshooting or reassembling it.

I'd recommend recapping the analog board and the power supply for the Hyperdrive. The Hyperdrive has its own dedicated power supply.

 

[dorkbert]

Installation for these things is a real nightmare. Bolting a 3.5" drive and another AC power supply in the confine of the compact case about an inch from the CRT neck and running all the wires and ribbon cable is a real bear. The Miniscribe drive they spec'ed out for this is generally unreliable, so finding one in working condition is quite a feat.

 

[AdamAnt316]

It's fairly rare. It's a coveted upgrade for many 128k and 512k owners. A working one is pretty rare. Either the HDD dies from stiction or the power supply goes. The reason it's sought after is because you can have a relatively fast mass storage device on 128k or 512k without swapping the ROMs out for a Plus. It was one of the first (if not the first) internal fast mass storage solution for the original Macintosh. The original Macintosh and its successor, the 512k, didn't natively support SCSI or indeed any attached fast storage device, and up until the Hyperdrive was released, the only options for mass storage were serial based. Serial drives by comparison were very, very slow and often still required you to boot off a floppy disk first, then restart to boot off the serial drive.

The Hyperdrive by comparison was really fast as it used SCSI. Not only was it fast, but it was also an internal solution. You didn't have to give up desk real estate for bulky external drives. It was very innovative for its time. If I remember correctly, GCC developed their own SCSI implementation that Apple eventually licensed or purchased for use with the Macintosh Plus.

http://macintoshgarden.org/apps/gcc-hyperdrive-software-drivers

I actually have a boxed Hyperdrive installation kit. I uploaded the software and most of the dealer installation manual (it was missing many pages, but the important pages were there.) It might be useful for troubleshooting or reassembling it.

I'd recommend recapping the analog board and the power supply for the Hyperdrive. The Hyperdrive has its own dedicated power supply.

Thanks for the reply! I figured these sorts of upgrades weren't terribly common; before I found this 512K, I was only vaguely aware of its existence. I'm rather amazed that it worked on the first try; my experience with 3.5" MFM hard drives has been rather poor, particularly with regards to the 20MB MiniScribe HD used in my Sun Remarketing-modified Apple Lisa 2. I'm not sure who made the hard drive used with this mod; the only marking I could find, on the defect sticker, looks like two 'M's stacked one atop another, with a lower-case 'i' to the right of them (it's hard to see due to the small amount of clearance between the top of the drive and the mounting bracket). Trying to search for "MMI hard drive" on Google brings up loads of info on Audi car audio systems, so I'm rather stumped at the moment. Anyway, here are some pictures of what I found when I cracked open the 512K's case:

Side view. You can see the hard drive with its mounting bracket, the line filter installed on top of the floppy drive (with ferrite beads), and the thin cable going to the cooling fan. The HyperDrive power supply is between the floppy drive cage and the analog board.

Corner view, for good measure. Rather cramped fit in there.

The wires which run power to the HyperDrive's power supply. Also, you can see collateral damage from the blown safety capacitor.

The culprit. Capacitor C38 on the 630-0102 (820-0082D) analog board. Have yet to track down the service manual to figure out the value of the part, and most of the case has been obliterated. Appears to be Y-rated, at the least.

A view of the cooling fan, for good measure. Not sure off-hand what the purpose of the box between it and the power cable is supposed to be. Some sort of temperature sensor?

Very cool that you have a boxed kit! How were these installed? Did you have to bring the Mac to a HyperDrive dealer, or could you opt to do it yourself if technically proficient? By the way, according to Wikipedia, the General Computer Company (Corporation?) had a hand in both Ms. Pac Man and the Atari 7800. As a collector of vintage video games, I find it fascinating that they moved into the computer accessory market afterwards, and created the HyperDrive.
-Adam

 

[AdamAnt316]

Installation for these things is a real nightmare. Bolting a 3.5" drive and another AC power supply in the confine of the compact case about an inch from the CRT neck and running all the wires and ribbon cable is a real bear. The Miniscribe drive they spec'ed out for this is generally unreliable, so finding one in working condition is quite a feat.

Yeah, it definitely looks like it was a pain in the ass to cram all this stuff into the little case! However, it seems to have been done about as well as could've been expected for a hack of this magnitude, and the fit-and-finish seems to be reasonable overall. As I mentioned above, the hard drive does not appear to have been made by MiniScribe, or at least, I couldn't see their logo on what of the top plate I could see. The only marking I spotted resembled something like "MMi".
-Adam

 

[GiGaBiTe]

The culprit. Capacitor C38 on the 630-0102 (820-0082D) analog board. Have yet to track down the service manual to figure out the value of the part, and most of the case has been obliterated. Appears to be Y-rated, at the least

Get that battery out ASAP, you can see the connection has the stereotypical green corrosion. It's only a matter of time before the battery spills its guts all over the logic board.

Clean out the battery compartment and use vinegar to neutralize the battery goo.

The blown capacitor is an X capacitor, not a Y capacitor. Y caps are generally blue and cylindrical, which go from the circuit to ground. An X cap is placed across the load in parallel. Judging from its proximity from the mains plug, its probably part of the transient filtering stage and usually has a value between .22 and .33uF. X capacitors usually have built in resistors, and it looks like that might be what failed inside it since the top is blown off. If you take the cap out, you should be able to see the rating on the side of the capacitor.

 

[AdamAnt316]

Get that battery out ASAP, you can see the connection has the stereotypical green corrosion. It's only a matter of time before the battery spills its guts all over the logic board.

Clean out the battery compartment and use vinegar to neutralize the battery goo.

The blown capacitor is an X capacitor, not a Y capacitor. Y caps are generally blue and cylindrical, which go from the circuit to ground. An X cap is placed across the load in parallel. Judging from its proximity from the mains plug, its probably part of the transient filtering stage and usually has a value between .22 and .33uF. X capacitors usually have built in resistors, and it looks like that might be what failed inside it since the top is blown off. If you take the cap out, you should be able to see the rating on the side of the capacitor.

Thanks for the reply. I have indeed pried the battery out of its holder. Not nearly as much corrosion leakage as the Maxell 1/2-AA in my Mac Classic, so I think the computer will be OK. There's other areas of corrosion on the chassis (particularly the left side under the analog board, and on the left rear near the port shield) that are far from the PRAM battery socket; not sure what's up with that. Couldn't find an obvious source for said corrosion, and I'm pretty sure it didn't come from the battery. I'll clean up what of it I can, in any case.

Thanks for pointing that out. I found a repair document which stated C38 as being a 0.1µF capacitor, but didn't mention anything about an X- or Y-rating. I've seen pictures of blown-up capacitors of this style before, but this is the first time I've had one blow up on me in one of my own computers (did once have a 0.47µF molded-paper capacitor blow up on me in an old tube radio, but said part was about 25 years older than this one, and not a safety-rated part). The sides of the C38 capacitor have also been blown apart, and you can see the soot residue on the large radial electrolytic capacitor across from it, so it went up rather violently.
-Adam

 

[GiGaBiTe]

Thanks for the reply. I have indeed pried the battery out of its holder. Not nearly as much corrosion leakage as the Maxell 1/2-AA in my Mac Classic, so I think the computer will be OK. There's other areas of corrosion on the chassis (particularly the left side under the analog board, and on the left rear near the port shield) that are far from the PRAM battery socket; not sure what's up with that. Couldn't find an obvious source for said corrosion, and I'm pretty sure it didn't come from the battery. I'll clean up what of it I can, in any case.

Someone could have spilled something on it at some point, old crackerbox macs tended to be abused once their useful lifespan was over and they went into storage.

Thanks for pointing that out. I found a repair document which stated C38 as being a 0.1µF capacitor, but didn't mention anything about an X- or Y-rating. I've seen pictures of blown-up capacitors of this style before, but this is the first time I've had one blow up on me in one of my own computers

A bit of brief research had people saying that the epoxy potting used tended to break down over time from the hot box nature of crackerbox macs having nearly zero ventilation. The other capacitors on the board are suspect as well.

(did once have a 0.47µF molded-paper capacitor blow up on me in an old tube radio, but said part was about 25 years older than this one, and not a safety-rated part).

Hopefully you recapped the entire radio. Old wax and paper capacitors in even the newest tube radios from the late 60s and early 70s are long since expired. The paper starts to go acidic and causes the capacitors to leak electrically. The electrically leaky caps start passing DC current through them and can red plate tubes, drive them really hard and burn out transformers. If the radio was stored in a hot environment, the allen-bradly style brown resistors commonly used can also fail from internal breakdown that causes internal arcing.

Just be careful inside those old tube radios, they're even more dangerous than a CRT. Pretty much everything can be high voltage DC in the range of 300-500 volts.

 

[Chuck(G)]

Steel-and glass Sprague "Vitamin Q" capacitors can fail in very spectacular and dangerous ways. I narrowly avoided having one embed itself in my ugly puss. Instead, it embedded itself in the ceiling tile seconds after I moved away to grab a meter.

Probably why they don't make them any more.

 

[AdamAnt316]

Someone could have spilled something on it at some point, old crackerbox macs tended to be abused once their useful lifespan was over and they went into storage.

Not entirely sure. I've seen corrosion like this on the chassis of other Macs; while some of it could be chalked up to battery leakage, that likely isn't the case with this one. I'll have to take some pictures of it next time I have the case open to show you what I mean.

A bit of brief research had people saying that the epoxy potting used tended to break down over time from the hot box nature of crackerbox macs having nearly zero ventilation. The other capacitors on the board are suspect as well.

According to this forum post, these old RIFA safety capacitors don't have a very good reputation in general. The resin shrinks over time, causing the case to crack, letting moisture in which leads to failure. Even NOS examples show signs of impending doom. :nervous: As for the rest of the capacitors, I will look into replacing them. None of the ones I could see had swollen tops, but I know it's only a matter of time with electrolytic capacitors this old.

Hopefully you recapped the entire radio. Old wax and paper capacitors in even the newest tube radios from the late 60s and early 70s are long since expired. The paper starts to go acidic and causes the capacitors to leak electrically. The electrically leaky caps start passing DC current through them and can red plate tubes, drive them really hard and burn out transformers. If the radio was stored in a hot environment, the allen-bradly style brown resistors commonly used can also fail from internal breakdown that causes internal arcing.

Just be careful inside those old tube radios, they're even more dangerous than a CRT. Pretty much everything can be high voltage DC in the range of 300-500 volts.

It's currently on the 'to-do' pile. The radio in question was an AC/battery portable, namely a Zenith TransOceanic. Highest voltage seen by the circuitry (apart from the input of the AC power supply) is somewhere around 90 volts. I generally ran it on a homebrew battery pack (six D-cells for filaments/A+, ten 9V batteries for plate/B+), and it actually worked fairly well in spite of still being equipped with 1950s/1960s parts. Only issues I had with it were fading when operated on AC power (likely due to a bad selenium rectifier), and the failure of the filament in one of the tubes (3V4). Other than that, it worked pretty well for a number of years.

I'm aware of the dangers of working on tube equipment. Fortunately, I haven't gotten any particularly nasty shocks from the gear I've worked on as of yet ***KNOCK ON WOOD***. I do my best to respect these sets, and keep one hand in my pocket if I think I might come into contact with the high voltage section.

Steel-and glass Sprague "Vitamin Q" capacitors can fail in very spectacular and dangerous ways. I narrowly avoided having one embed itself in my ugly puss. Instead, it embedded itself in the ceiling tile seconds after I moved away to grab a meter.

Probably why they don't make them any more.

Yikes! :bigeyes: How the hell did that happen?! I've never heard of a Vitamin Q capacitor exploding in that fashion. Generally, they're considered quite reliable, and paper-in-oil capacitors are sought-after by audio nuts. Of course, that's not always the case; Japanese paper-in-oil capacitors as used in early tube hi-fi equipment like the Sansui AU-70 are generally referred to as being akin to firecrackers, and even the 'bathtub' capacitors used in old military radio gear have been known to spring leaks, both in the electrical and literal senses.
-Adam

 

[olePigeon]

That's the most common point of failure in the miniscribe drives is the stepper motor. It'll seize up and can even damage the platters when that happens. I've read that people got dead Miniscribes working again by lubricating the stepper motor shaft.

Someone correct me please if I'm wrong, but it might be worth getting some lubrication oil and doing some preventative maintenance on that old Miniscribe. Here're a couple of videos showing different types of hard drives with steppers being brought back to life with some oil:

MiniScribe
Western Digital

 

[AdamAnt316]

That's the most common point of failure in the miniscribe drives is the stepper motor. It'll seize up and can even damage the platters when that happens. I've read that people got dead Miniscribes working again by lubricating the stepper motor shaft.

Someone correct me please if I'm wrong, but it might be worth getting some lubrication oil and doing some preventative maintenance on that old Miniscribe. Here're a couple of videos showing different types of hard drives with steppers being brought back to life with some oil:

MiniScribe
Western Digital

Thanks for those links. The issue I have with the MiniScribe drive in my Apple Lisa 2/Macintosh XL is some form of head stiction, I think. I turn the computer on, and the drive fails to spin up unless I tap the bottom of it with the handle of a screwdriver, or another blunt object. This eventually caused the system folder to become corrupted, and I haven't used the Lisa since. I'm hoping there's a way to low-level format another 3.5" MFM hard drive to take its place, but I don't have especially high hopes.

I'm still not sure who made the drive used in this Mac 512K (edit: looks like MMI is indeed the name of a hard drive manufacturer, and their hard drives were used in these HyperDrive add-ons, as mentioned here), but it's spun up and worked correctly each time it was called upon. Somewhat distressing that there isn't a clear way to shut the thing down, since the 'Shutdown' option in these Macs acts more like a restart, and the drive dutifully boots the OS. Was hoping there would be a way to park the heads on the drive before shutdown, but I don't think they included a program to do this. In any case, at this point, I'm more concerned about the Rifa capacitor which blew its top. :sigh:
-Adam

 

[Shred]

I’m a bit late to this discussion, but I remember the Hyperdrive mod well. It was very unusual for a third-party add on, in that provided that it was installed by a qualified Apple technician, it did not void the computer’s warranty with Apple. The HyerDrive was specifically mentioned in the Apple service documentation.

The drive was an ST-506 drive, so did not use a SCSI interface like the later Macintosh drives. The Australian ones may have been a bit different to the OP’s system: I recall the switchmode power supply for the hard drive being adhered to the back half of the case with double sided tape.

Here’s a picture of the interface board that I uploaded for sharing on another vintage computer site some years ago. I have this board (but not the drive or PSU) in my junque box somewhere. (Junque = good junk that will come in handy one day).

HyperDriveBoard.jpg

 

[AdamAnt316]

I’m a bit late to this discussion, but I remember the Hyperdrive mod well. It was very unusual for a third-party add on, in that provided that it was installed by a qualified Apple technician, it did not void the computer’s warranty with Apple. The HyerDrive was specifically mentioned in the Apple service documentation.

The drive was an ST-506 drive, so did not use a SCSI interface like the later Macintosh drives. The Australian ones may have been a bit different to the OP’s system: I recall the switchmode power supply for the hard drive being adhered to the back half of the case with double sided tape.

Here’s a picture of the interface board that I uploaded for sharing on another vintage computer site some years ago. I have this board (but not the drive or PSU) in my junque box somewhere. (Junque = good junk that will come in handy one day).

HyperDriveBoard.jpg

Thanks for the reply! I hadn't heard about the warranty thing. I'm guessing that Apple tacitly approved of the modification, at least on the quiet (and after Steve Jobs had left the company, of course). Makes me wonder why it took them two more years to figure out a way to include an internal hard drive within a compact Mac with the SE. :confused1:

Yeah, I figured it wasn't a SCSI interface which attached to the CPU, but wasn't sure exactly how it did its thing. As for the power supply location, I'm guessing where it was installed probably depended on the design of the power supply, and possibly the whim of the dealer who installed it. The (partial) installation instructions linked to elsewhere in this thread show that there were at least two different designs of power supply; I believe both were intended to mount to the side of the floppy drive cage, though it only shows the ones meant for 110V use, so the 220V power supply might've been too big to fit in that location.

Thanks for the picture of the interface board! I have yet to remove the logic board in my HyperDrive-equipped 512K, so I haven't seen exactly what the add-on board in mine looks like. There were different versions of the interface board for 128/512K and Plus logic boards, according to the aforementioned installation manual. Both, of course, were rendered obsolete by the introduction of the SE and its internal SCSI hard drive; once the blown-up capacitor is replaced, I'll have to do a speed comparison between this HyperDrive-equipped 512K and my internal HD-equipped SE.
-Adam

 

[DFinnigan]

Thanks for the reply! I hadn't heard about the warranty thing. I'm guessing that Apple tacitly approved of the modification, at least on the quiet (and after Steve Jobs had left the company, of course).

This was a big deal in 1985. Don't guess; read this article: Apple proposes detente with HyperDrive. This all happened after Jobs left Apple. As the article states, the HyperDrive was used in Macs within Apple, and there was speculation that Apple would market it themselves.

Makes me wonder why it took them two more years to figure out a way to include an internal hard drive within a compact Mac with the SE. :confused1:

In 1984/85, the plans within the Macintosh team for a hard drive were a lot different than what we generally think of today. There were plans for a network file server. I'm going to write an article on this in my Mac 512K blog because the story is (I think) really fascinating for the time.

 

[Al Hartman]

Corvus made a Constellation Interface (flat cable) for the Mac 512k that attached to the floppy port. I believe it required a Boot floppy.

 

[DFinnigan]

Right. Apple's product was going to be the AppleBus File Server. Bunch of really interesting documents on BitSavers site.

 

[AdamAnt316]

This was a big deal in 1985. Don't guess; read this article: Apple proposes detente with HyperDrive. This all happened after Jobs left Apple. As the article states, the HyperDrive was used in Macs within Apple, and there was speculation that Apple would market it themselves.

Very interesting! I hadn't read that article. Information about third-party Mac modifications seems to be fairly thin on the ground. Also, I wasn't sure exactly what Apple's position on them was; I figured they wasn't terribly keen on them, while other manufacturers were likely a bit more lax, depending on the mod. Of course, most systems back then were intended for more expandability than the "closed system" of the early Macintosh models.

In 1984/85, the plans within the Macintosh team for a hard drive were a lot different than what we generally think of today. There were plans for a network file server. I'm going to write an article on this in my Mac 512K blog because the story is (I think) really fascinating for the time.

I would definitely be interested in reading it. If you need any pictures of a HyperDrive-equipped Mac for your article, please let me know. Once I find a suitable replacement for the safety capacitor (wouldn't mind reading an article on that subject, as well), I'll likely be taking this unit apart to some degree, and could take some pics of the innards beyond what I've posted thus far.
-Adam

 

[DFinnigan]

I would definitely be interested in reading it. If you need any pictures of a HyperDrive-equipped Mac for your article, please let me know.

Thanks, I will. I just hope I have time to write!

Once I find a suitable replacement for the safety capacitor (wouldn't mind reading an article on that subject, as well)

Consider this: PME271M610MR30 film capacitor

 

[olePigeon]

I can put you in touch with the lead engineer for GCC at the time for your article. I had set up to do an interview with him in regards to the HyperDrive, but he's been elusive. He hasn't responded to my emails for a long time. I haven't heard back from him since I sent in the interview questions. I'm using pronouns because he said he doesn't want his name posted on internet forums, so I've respected his wishes.

GCC did do an inhouse SCSI implementation that Apple eventually used in the Plus (along with John Bass's design) but I must be confusing two different (but related) projects in regards to the Hyperdrive.