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Mighty Jabba

Took a gamble on a Mac Plus and SE that appeared to have accelerator cards...

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While browsing eBay on two separate days I found a Mac Plus and a Mac SE that both seemed to have accelerator cards installed. The sellers didn't mention it in either case and seemed to know nothing about it, so it while I didn't pay too much for them, it was a bit of a gamble. Still, I'm kind of fascinated about this kind of modification, so I decided to see what I would end up getting. I'd like to get a little advice about what to do with them. So far, only the Plus has arrived. As you can see, there is a "68030 Power/Total Systems" badge on the front, and a sticker on the back saying that you can't just slide out the logic board as you might normally do, and it also mentions the "Gemini 020/030 card manual" so I'm assuming that the card is called the Gemini from Total Systems. There is also what appears to be a SCSI port in the battery compartment. (I removed a battery that was just starting to corrode.) It came with zero software or accessories beyond the power cable.

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The internal floppy appears to be borked in some way -- the mechanism is in the wrong position to receive a disk, and the machine wouldn't even boot from my Floppy EMU while the internal floppy cable was connected. But it did boot just fine when I disconnected it. It shows that it has 4MB of RAM, but in terms of speed, I can't say that it feels any faster than my other Plus, but I haven't done any real tests. It's certainly no speed demon. Opening it up revealed that there was indeed an accelerator board inside.

 

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There is something mounted on top of the floppy drive in a way that makes it necessary to remove everything in order to get at the floppy. I'm pretty reluctant to take everything out just to get at the floppy, but is there anything I could try to fix it with it still installed?

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Can anyone tell what is mounted here? I wondered about the possibility of a hard disk, but I think it's some other sort of card.

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They also installed a fan.

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I'm curious if I'm actually getting any additional speed from the accelerator as it is or not. Worst case scenario, I guess I have a Plus with 4MB of RAM and a SCSI port, so that's pretty cool. Any advice about what I should do regarding the software? Keep in mind that I can only have one thing attached at once (external floppy or the Floppy EMU -- unfortunately I have no SCSI devices but am planning to get an SD2SCSI at some point).

Edited by Mighty Jabba

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Quick update: I did manage to get the floppy mechanism back into position so that it would accept a disk, and it does function, but (of course) the eject mechanism appears to be shot. The weird thing is that when I tried to boot it with both the internal floppy drive cable and an external floppy connected, it made the boot chime and then just never stopped. Is that a known issue of some kind?

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That’s a great accelerator. I have one too. The thing mounted behind the floppy is a dedicated power supply for your accelerator board. It’s wired directly to AC power at the Mac Plus switch using test clips so it puts zero drain on your original analog board. 

 

To get the speed benefit and have the system recognize it as an 030 you need to run the proper drivers. GemStart is probably the best choice. It’s available on the Garden and elsewhere. It will absolutely fly. I can probably help if you need assistance configuring it. 

 

By the way, your Plus has a stock SCSI port so you don’t really need that SCSI out thru the battery compartment. That’s a great feature if you want to install this board as a fully removable upgrade on a 128k though (which is what I did)!  

Edited by Crutch

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Great, I'm glad to hear from someone who has one. Can you explain what exactly I need to do to take advantage of the speed increase? Where would I put the Gemstart 2.1 control panel and does it matter what OS version I use? Is it possible to do add it to a boot floppy?

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The accelerator should run without any drivers but not all features will work. I see you have RAM and cache on yours so a driver will be needed to activate those.

 

Depending on how much RAM you got installed you might want to look into Connectix CompactVirtual as well to use the additional RAM. You need a hard drive to boot from and install the software though for that.

If you only want to install the accelerator driver that will fit on a floppy disk probably.

 

Gemstart just goes into the system folder on System 6 or into the control panels folder in System 7.

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I've been having some issues trying to get this to work. When I tried adding Gemstart 2.1 to the system folder of my emulated hard disk on the Floppy EMU, it hangs at the "Welcome to Macintosh" screen, and the Floppy EMU gives me an error on the screen about a "changed write state" (if I recall correctly). So I tried making a boot floppy, and then I get an error after the very cute Mac with sunglasses animation for Gemstart. It either says that the Finder is busy or damaged, or that there is no coprocessor installed (seemly randomly). The bizarre thing is that I actually got it to work once, and I have no idea why! This is all booting into System 6 with Gemstart 2.1. I don't have a way to boot this machine using System 7 right now, so I'm wondering if maybe my board is somehow incompatible with Gemstart 2.1 and needs Gemstart 3.0 instead, but that doesn't explain why it worked once. I will say, that while I had it booted, it did seem very nice and fast, although I didn't have much of anything on the boot disk that I could test it with.

 

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Edited by Mighty Jabba

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3 hours ago, Crutch said:

.  .  .  your Plus has a stock SCSI port so you don’t really need that SCSI out thru the battery compartment. That’s a great feature if you want to install this board as a fully removable upgrade on a 128k though (which is what I did)

But the Plus has no internal SCSI connector. Does that battery door connector's ribbon cable hook up to the accelerator? If so, you'd have two SCSI Controllers/Chains when it's installed in a Plus? It almost looks to me like an internal HDD might be looped back from the external SCSI Port using that cable setup. [}:)] There's plenty of room for mounting a hard drive on the backside of that PSU bracket and it looks oversized for powering an accelerator alone. Interesting sheet metal, what does the wiring setup look like?

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2 minutes ago, Trash80toHP_Mini said:

But the Plus has no internal SCSI connector. Does that battery door connector's ribbon cable hook up to the accelerator?

The battery door ribbon cable connects to the accelerator board on the bottom left, right above the chip that says "LOGIC" on it. There are a lot of unused connectors on this board, I noticed.

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@Trash80toHP_Mini you can indeed loop back an internal HDD from that connector. I have done it on my 128k! Mounted to the back of the PSU just as you suggest. The best thing is, unlike the stock Plus SCSI bus, this board’s SCSI bus provides term power so I can power my internal SCSI2SD directly from the bus. It is awesome. I’ll post pictures sometime but it’s in pieces on my bench right now. 

 

... also if I recall it disabled the motherboard SCSI when installed on a Plus, now that I think about it. Not sure I’m remembering correctly though. 

Edited by Crutch

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@Mighty Jabba yeah it’s finicky to set up the first time. I’ve had similar problems. It actually looks like it’s flaking after loading the driver properly. I assume you are running 6.0.8 or similar with NO other extensions? I’ve actually never tried booting with the accelerator from floppy before. 

 

(By the way, you indeed don’t have an FPU. You should pick up a cheap 68882 on eBay and pop it into that socket on the board! Still, it should run fine without.)

 

@Bolle hmm, my Gemini 020/030 feels slow as molasses - basically unaccelerated - when I run it without the driver. I don’t understand why. Does the cache make most of the difference? I found the drivers make a massive massive difference even to mundane things like the Apple menu populating. 

Edited by Crutch

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26 minutes ago, Crutch said:

@Mighty Jabba yeah it’s finicky to set up the first time. I’ve had similar problems. It actually looks like it’s flaking after loading the driver properly. I assume you are running 6.0.8 or similar with NO other extensions? I’ve actually never tried booting with the accelerator from floppy before. 

Yes, I just wanted to see it run with a barebones system folder to make sure it was working, and also because my Floppy Emu doesn’t seem to play nice with the Gemstart extension I am limited to what I can fit on a floppy. I went ahead and ordered the external version of SCSI2SD, which I hope will allow me to actually run a “real” system, and probably System 7.x.  What version of the OS and Gemstart are you using with yours? Interesting about the coprocessor. I’ll have to order one. 

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As far as the coprocessor error, that could possibly be bogus. When the system software cannot find an appropriate code, it defaults to the last code in its list...which is the coprocessor error. So there may be something else going on.

 

As for the floppy, there can be a few things going on. The “disk in” sensor may be stuck down, and the Plus is the attempting to forever eject a disk that isn’t there, causing the error you described. I’d check that first.

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Yes I don’t really think the errors are accurate, but of course something is going wrong. In any case a coprocessor looks to be extremely cheap so I may pick one up.

 

As for the floppy, although I was able to get it working, I have tried several times and the machine won’t start up at all if I have the internal floppy cable connected and also something attached to the external floppy port (either an external floppy or Floppy Emu). I just get a garbled screen. This is another reason I want to try a virtual SCSI hard disk.

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This is a freaking cool Plus!! That must be pretty rare, definitely worth keeping it. I did not know you could get accelerators like that for the Plus.

 

Accelerators tend to cause havoc with the HD20 support on the Floppy Emu, so it's not supported AFAIK.

 

My SE/30 has a Daystar accelerator and I did manage to get HD20 support working with my Floppy Emu to boot my custom disk image, so it's possible that some work.

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I’m running GemStart 3 with 7.0.1.  I think that might be the latest supported version of System 7 but that’s from memory, I may have just stuck to that version so the Plus doesn’t slow down.  I will put everything together this weekend and run some tests - see if I can get it to boot from a floppy running 6.0.8 with GemStart 2.1.  I know that it boots fine from my (real) HD20 running 6.0.8.  I love the sound of that HD20 ...

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5 hours ago, Crutch said:

@Trash80toHP_Mini you can indeed loop back an internal HDD from that connector. I have done it on my 128k! Mounted to the back of the PSU just as you suggest. The best thing is, unlike the stock Plus SCSI bus, this board’s SCSI bus provides term power so I can power my internal SCSI2SD directly from the bus. It is awesome. I’ll post pictures sometime but it’s in pieces on my bench right now. 

Very cool, I'd love to see pics of your setup, Is there any provision on the aux. PSU for installing a hard drive? If not, a Y-cable would likely have been part of the HDD installation kit? The four holes on the bracket look just about perfect for mounting a 3.5" HDD sled horizontally? The larger holes at the top look to be for thru bolts. If the smaller holes on the bottom are tapped for machine screws, they almost certainly planned for internal 3.5" HDD installation.

 

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Having it in pieces on the bench makes for a great photo op. [;)]

 

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Sheet metal bracket's mounting bolts have nuts on the bottom side so it's installed and in place when the Logic Board/Accelerator is slid into place. Looks like it may be a royal PITA to remove/install the A/B connector?

 

Edited by Trash80toHP_Mini

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7 hours ago, Crutch said:

... also if I recall it disabled the motherboard SCSI when installed on a Plus, now that I think about it. Not sure I’m remembering correctly though. 

 

That makes theoretical sense.   The driver built into the Plus ROM must know the address of the SCSI chip.   I don't think Apple added the ability to support more than one SCSI host until SCSI Manager 4.3, so way back in the Plus's day, there was probably one hard coded address for where the SCSI chip was expected to be on the bus.   Or maybe a pointer to a table, where the address could be stored.

 

But in either case, only one address ultimately, for the SCSI bus.   There is no way for a machine of the Plus's era to control/address more than one SCSI chip, absent a very substantial DA/extension.

 

So your observation is exactly what I would expect in practice.  Only one SCSI controller can be active at a time.

 

I know that Newlife told me that their SCSI implementation was considerably faster than the Plus's, so it is likely the Gemini's is as well.  I think the after market upgrades have the improvement in how SCSI is handled that the SE had.   I can't remember what that was at the moment...

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Here’s my setup, in pieces right now because some pins on the 68k socket atop the Killy clip broke during routine maintenance and I had to order another socket online. Fortunately someone sells these on eBay!

 

It’s a 128k “enhanced” with a pair of rev C Plus ROMs from an eBay seller (I only had the older Plus ROMs which have annoying SCSI issues). The accelerator wouldn’t run with the 64k ROMs. The original fan wanted 120v and was connected to the A/B with test clips, I replaced it with a modern Noctua fan spliced into the accelerator’s PSU. 

 

Unfortunately the PSU bracket won’t fit with any of the 400k floppy drive mounting brackets I’ve found, so I had to swap in an 800k drive to make it work. But I am still calling it a 128k not a Plus because the logic board just says “Macintosh”!

 

Interestingly mine doesn’t have the mounting holes (or whatever they are) on MightyJabba’s PSU bracket. The screws you see there are for the PSU itself of course. 

 

The A/B connector is easy to remove, you can pull it right up through the hole there. The accelerator doesn’t get in the way. You obviously need to pry the whole thing out with a screwdriver though, which isn’t too bad after the chassis loosens up after a few tries. 

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Edited by Crutch

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Aha! I was thinking SE/30 A/B connector, forgot about the location and connector type in the earlier Macs.

 

28 minutes ago, Crutch said:

Interestingly mine doesn’t have the mounting holes (or whatever they are) on MightyJabba’s PSU bracket. The screws you see there are for the PSU itself of course. 

That's the first thing I noticed!

 

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I really like this shot, there's all kinds of room for a 3.5" Hard Drive in there. HDD bracket/sled could easily be bolted up just by using longer screws (machine screws or sheet metal screws?) for mounting the PSU to the bracket. Fabulous kluge you guys have there.

 

4 hours ago, trag said:

I know that Newlife told me that their SCSI implementation was considerably faster than the Plus's, so it is likely the Gemini's is as well. 

Newlife! That's the one thing I really wish I'd held onto. I had a board that was slated to have TTL Video out in my first Mac. That was a 512k that came bundled with an ImageWriter Wide Carriage I used with ThunderScan when the SE/Radius16 arrived.. I don't think they ever finished a driver for the video port. Didn't want to screw up my 512k board so I got a "worthless" 128k board from Shreve for my Hackintosh/Cat Mac project. Worked great for "digitizing" artwork in Fontographer at home by night for use with the main system at work by day. The Newlife board made the 512k faster, but starting out with just the FDD worked well enough long before that. It's amazing what folks did with Fontographer on Madison Avenue well before Illustrator became the SECOND Illustration program to ship.

 

I always wanted a Gemini 030 board from Total Systems as an upgrade for the SE/Radius16, but never got one. I'm a bit jealous, guys. :mellow:

Edited by Trash80toHP_Mini

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Thanks for the photos and info, Crutch. I've been doing some research on this accelerator. There was a very extensive article on accelerators in general in the August 1990 issue of MacUser ("Chasing the IIfx: Accelerators"), which gave the Gemini board a good review, and they said it was your best option if you wanted to upgrade a Plus.

 

I also found a PDF of Total Systems' entire catalog, with some speed comparisons and pricing. I'll try and upload it here since I'm not sure where I got it from. I think my particular card is the GEM325PX, which would have had a list price of $2295, although even they apparently discounted them fairly heavily. They certainly made a lot of upgrades, and this was just one company! The landscape is very different today.

 

Here is the catalog:

TNM_68020-68030-68040_accelerator_family_Macintos_20171214_0077.pdf

Edited by Mighty Jabba

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Regarding the SCSI question, this quote from MacUser indicates that the accelerator solves the Plus's wonky SCSI implementation (which to be honest I had no idea about -- I'm still learning).

 

Quote

"Your best bet is the TOTAL SYSTEMS Gemini line of accelerators. The Gemini 020 Plus ... is both cost-effective and speedy, and the Gemini 030 Plus... can boost your Plus' performance well past that of a llci. As an added—and very important—benefit, Gemini accelerators also solve the Plus' SCSI handshaking problems when you add TOTAL SYSTEMS highly recommended GemKit option...."

So I think that the additional SCSI port was an optional extra, and was intended to be a better version of SCSI rather than an additional port.

Edited by Mighty Jabba

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LOL! Beat me to it. :p

 

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That GemKit option sounds interesting? It's not an add on to the accelerator board. Crutch says the ribbon cable for the DB25 SCSI connector on the replacement battery cover plugs onto that long row of headers on the back. ISTR an optional video card plugging in there as well.

 

What handshaking problems did the the Plus have?

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