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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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According to page 99 of the MacUser issue I linked, the GemKit included the fan, power supply, and fast SCSI. So it seems less like an option and more like something you would have to buy to actually install the thing. There is also a mention of GemKit in a Mac Zone ad earlier in the magazine that says, "GemKit (allows user to put Gemini 020/030 Accelerators in Mac+, 512kE, 512k, & 128k. Includes internal fan, SCSI port, and space for extra RAM memory)."

Edited by Mighty Jabba

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edit: beat me to it by about a minute again!:lol:

 

Looks like you both have the GemKit. Is the SCSI controller on the Accelerator socketed?

 

836835279_MacUser-_9008-02-Gemini-TotalSystems.thumb.JPG.25505b47c2d06e4255cc620c824df412.JPG1653419177_MacUser-_9008-01-Gemini-TotalSystems.thumb.JPG.9f4304ae4e7aadb98594b808717f6226.JPG

 

Maybe GemKit adds the fan and better drivers? Have either of you got the fan?

Edited by Trash80toHP_Mini

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Wow that’s some good stuff. Thanks for sharing all this material. 

 

Sorry if I gave the wrong impression, the SCSI ribbon doesn’t connect to the row of pins in the back but rather to P1 here. It’s definitely not a standard internal SCSI ribbon. 

 

My SCSI chip is NOT socketed which makes the GemKit sound kind of weird since one gets the SCSI chip without it. The key to “best SCSI performance” is ... a PSU and a fan? Yes, mine came with a 120v AC powered fan which I replaced with a much quieter Noctua one I spliced into the PSU. 

 

By the way while it does provide term power and may be faster, the Plus’s handshake issues are due to code in the 128k ROM and I can confirm that the Gemini alone definitely does NOT fix them ... I had to get updated Rev C ROMs to do that. (The symptoms as I recall include that the Mac won’t boot if any SCSI device in the chain is off when you switch it on, which usually means I can’t restart my Mac with my SCSI2SD hooked up without switching it off and back on with the switch on the back, or I get stuck at a black screen - some timing issue I’d guess, despite having followed these guidelines below)

 

C17B64BA-DBF0-4CAC-84C0-2B44B4368796.jpeg

Edited by Crutch

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7A3FF6F8-F543-465D-B496-610FE125D032.jpeg

 

1220878909_MacUser-_9008-04-Gemini-TotalSystems.JPG.fc3e4be7268e0ac87009f0b9a942cbc4.JPG

 

How is your fan mounted? The GemKit sheet metal looks significantly taller than yours with bent returns at the top for mounting the fan and what appears to be a different PSU?.

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Sorry if this has already been addressed, but this explanation about the Plus’s SCSI problem seemed good (from the MacUser article):

Quote

The Mac Plus suffers from a singular problem with hard-disk performance - its SCSI controller lacks a handshaking connection, which means the Mac Plus microprocessor can never be certain whether its hard disk is ready to receive data. To avoid losing vital information, the whole system waits long enough to be sure everything has gotten to the disk, wasting vital microseconds that could be used for processing. The only way around this problem is to improve your Mac Plus' SCSI system. The Total Systems GemKit for its Gemini series of accelerator does just that.

 

Edited by Mighty Jabba

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Thanks, not covered yet AFAIK. @trag explained some of that. Mac Plus was Apple's first shot at implementing SCSI and they got so much wrong, right down to the sub-standard DB25 connector in place of Centronics-50. But the DB25 was already in use, being mounted on the replacement battery cover by SCSI upgrade kit makers. Apparently Total Systems got their implementation of SCSI right, deactivating Apple's sorry excuse. But then again the ANSI spec was released at about the same time as the Plus or even after the Plus, so who knows? Total Systems had a year or two to work the kinks out, the 68030 on those boards wasn't released until 1987.

 

I took another look at crutch's pics and see the fan located next to the PSU? It's on the opposite side in the GemKit pic?

 

edit: maybe they mounted the PSU on the opposite side so the assembly? That would be much more photogenic for adverts.

Edited by Trash80toHP_Mini

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Slight thread hijack, apologies in advance...While we are on the topic of accelerators, does anyone know which magazine has details about the socketed Daystar 030 accelerator for the SE/30 ? I'd like to know the original pricing etc.

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15 hours ago, joshc said:

Slight thread hijack, apologies in advance...While we are on the topic of accelerators, does anyone know which magazine has details about the socketed Daystar 030 accelerator for the SE/30 ? I'd like to know the original pricing etc.

Who boy, that took some Googling.  This is the announcement from 1992 for the socketed version of the SE/30 PowerCache (as opposed to the Universal PowerCache that can plug into various PDS slots with or without an adapter). 

 

http://www.verycomputer.com/26_92fabf268810d0da_1.htm
 

Quote


The SE/30 PowerCache will be available <in August 1992>, exclusively
through dealers and distributors worldwide.  SE/30 owners with the
Universal PowerCache can swap their accelerator for the new SE/30
PowerCache at no charge.

     Suggested Retail Prices:
     -----------------------
     33 MHz SE/30 PowerCache                        $ 699
     33 MHz SE/30 PowerCache with 68882 math chip   $ 899
     40 MHz SE/30 PowerCache                        $ 899
     40 MHz SE/30 PowerCache with 68882 math chip   $1099
     50 MHz SE/30 PowerCache                        $1399
     50 MHz SE/30 PowerCache with 68882 math chip   $1699

 

 

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Just a quick update: I received my SCSI2SD today and after a few configuration issues I have managed to boot the accelerated Plus from it, into System 6 using Gemstart 2.1, and I think it’s working fine. I am wondering if there isn’t some kind of incompatibility between the accelerator and the Floppy Emu since it just seems unstable when I’m using it. But otherwise I think I’m on my way. The system is very fast with the accelerator enabled!

Edited by Mighty Jabba

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7 hours ago, pcamen said:

Who boy, that took some Googling.  This is the announcement from 1992 for the socketed version of the SE/30 PowerCache (as opposed to the Universal PowerCache that can plug into various PDS slots with or without an adapter). 

 

http://www.verycomputer.com/26_92fabf268810d0da_1.htm
 

 

Thanks for this, a very interesting read! 
 

3 hours ago, Mighty Jabba said:

Just a quick update: I received my SCSI2SD today and after a few configuration issues I have managed to boot the accelerated Plus from it, into System 6 using Gemstart 2.1, and I think it’s working fine. I am wondering if there isn’t some kind of incompatibility between the accelerator and the Floppy Emu since it just seems unstable when I’m using it. But otherwise I think I’m on my way. The system is very fast with the accelerator enabled!

 

Nice one, glad you got it working. How do you find the performance with the Floppy emu? I tried mine with my SE/30 with Daystar accelerator and I thought opening apps and switching between apps was a bit slow with the Floppy emu, but maybe I’m doing something wrong...

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1 hour ago, joshc said:

Nice one, glad you got it working. How do you find the performance with the Floppy emu? I tried mine with my SE/30 with Daystar accelerator and I thought opening apps and switching between apps was a bit slow with the Floppy emu, but maybe I’m doing something wrong...

It's not super fast, although it is emulating a floppy, so maybe that is just the way it is. I haven't really used it enough (or even had enough experience with compact Macs, to be honest) to be able to judge the speed.

 

By the way, I believe the second "possibly accelerated system" -- the Mac SE -- should be arriving tomorrow. Fingers crossed.

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The floppy interface just doesn’t allow for very fast transfer speeds vs. SCSI, so FloppyEmu is inherently limited. It’s why the original HD20 - which connected to the external floppy port - was so much slower than the 20SC back in the day. You’ll enjoy the much faster speeds with any SCSI device ... especially a SCSI2SD! Glad you got it working!

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Thought as much, I'm still glad I got a Floppy emu, it's a very handy tool, but I will be looking for a more permanent solution, probably a SCSI2SD...unfortunately when you have 7 Macs (OK, nobody forced me to get that many Macs, but you know...) that all need a permanent drive replacement, it gets costly very quickly.

 

Looking forward to seeing the 'possibly accelerated' SE soon! :rambo:

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7 hours ago, joshc said:

when you have 7 Macs that all need a permanent drive replacement, it gets costly very quickly.

That's the reason why I gave up on vintage Macs with internal hard drives and switched to Apple II exclusively for many years. Now I'm back to pre-SE, floppy-driven Macs.

 

Failing or lack of hard drives ranks right up there with failing capacitors as the most annoying aspect of vintage Macintosh computing. :-(

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Great news that you've got it up and running!

 

I'll add to that: for me, finding non-functional and flaky manual inject FDDs has become a massive PITA. Has anyone done a repair howto for those as has been done for the earlier drives?

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Turns out the package I thought was going to be the second system was something else, so I guess we’ll have to wait a bit longer. 

 

By the way, I tried a number of different combinations of settings so it’s possible I’m misremembering, but I think I still had to use the special SCSI2SD settings designed for the Plus, even though I was using the additional SCSI port. And I also had to use an additional USB power adapter for the external SCSI2SD unit since it apparently requires more power than the port can give it. 

 

Now I have four 2GB virtual hard disks (actually more like 1.89GB apiece) all mounted on the system at once, which is pretty impressive for a Plus, but I’m not sure what I’m going to use all the space for. 

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Finally managed to get System 7.1 installed. As I mentioned, Floppy Emu seems to have issues with this machine, so I had to use another Mac that was able to use both the SCSI2SD and Floppy Emu at the same time in order to install it, but it seems to be working fine with Gemstart 3.0, and it's a real speed demon compared to all of my other compact Macs! (Admittedly, the newest one I have is an SE, but it's still very impressive.) It's a bit of a shame that I can't really get to the floppy drive to fix the darned eject gear, but I am very wary of removing all of the various parts of the accelerator card and power supply just for that, so I guess I will just use the old paperclip method when I do need to use a real floppy.

 

Am I right that 7.1 is probably where I should draw the line for this machine?

Edited by Mighty Jabba

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The advice I've gotten points about there for 030 machines, maybe going up to 7.1 pro? Don't know about an upgraded to 030 machine, but it's been recommended for a stock 030.

 

I've been recommended 7.5.3 max if you've got an 040. And 7.6.1 for PPC machines pre-G3.

 

Again very general stuff.

 

 

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11 hours ago, Mighty Jabba said:

By the way, I tried a number of different combinations of settings so it’s possible I’m misremembering, but I think I still had to use the special SCSI2SD settings designed for the Plus, even though I was using the additional SCSI port. And I also had to use an additional USB power adapter for the external SCSI2SD unit since it apparently requires more power than the port can give it. 

 

That’s interesting and a bit surprising, I am running a SCSI2SD 5.1 externally on mine right now just using SCSI bus power.  Have you checked the voltages on the accelerator PSU?  (I also had to still run the special Plus SCSI settings.)

 

I recall based on something (maybe the GemStart Readme?) that GemStart 3.0 doesn’t like System version above 7.1 but that might be wrong.  

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5 hours ago, Crutch said:

That’s interesting and a bit surprising, I am running a SCSI2SD 5.1 externally on mine right now just using SCSI bus power.  Have you checked the voltages on the accelerator PSU?  (I also had to still run the special Plus SCSI settings.)

I tried again, and you're right -- it will work without the extra power supply. I guess I got confused when I was trying various combinations of settings. That's good, since it's one less thing to worry about.

 

The Gemstart 3.0 readme says that it is compatible with all versions of system 7 that were available at that time, which was up to 7.1. So it's possible that it could work with 7.5.X. Maybe I should give it a try. How much of a performance hit do you think there would be?

Edited by Mighty Jabba

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I think you’ll find it much slower. I run 7.1 on my Plus and 7.5.5 on my 50MHz SE/30. I’m not sure I would love 7.5.5 even on that accelerated Plus ... but I could be wrong! Would be interested to hear if it works. 

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The seller I bought the second upgraded machine from was taking their sweet time shipping it and never gave me a tracking number, and now I've been told that they accidentally shipped it to a location 2,000 miles away from me. Supposedly they will be shipping it straight from there to me rather than sending it back to him (which would involve another cross-country trip), but I'm not super impressed with this guy. So we'll see if I actually ever get it.

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