Macintosh Plus 1MB oddity (?)

[moszio]

Hey guys,

There are more and more mystical things and it's starting to worry me
I got a Macintosh Plus 1MB. It works flawlessly, reads floppy, boots, everything is fine. I took it apart and noticed several things.

1. does it have a hdd, 40SC (why?)
2. There is a power supply next to the floppy drive.?

they don't lead anywhere, they're just there

Whoever did it, I don't know what the purpose was, but I don't know what this is.
Have you seen such a modification?

Have a nice day,
Best Regards,
moszio

 

[wskjinfen]

A hard drive was added, and the power supply may be for the hard drive. Is there any sign of modification on the logic board?

 

[moszio]

hi, thanks for the answer, it doesn't lead anywhere, I don't see any signs of modification on the motherboard. The extra power supply doesn't come with a 4-pin connector either, it's missing

 

[jdmcs]

I've seen these power supply upgrades in photos, but not in person - they were part of some upgrades because the original power supplies had little margin for upgrades.

I suspect there was an accelerator card in this Mac Plus that has been removed, as normally you wouldn't be able to install an internal SCSI device due to there being no internal SCSI header. Some accelerator boards did include SCSI for an internal SCSI drive, and that hard drive could have been plugged into that. Some accelerator boards also included a supplementary power supply like the one in your Plus. And for many of these accelerator boards, upgrade memory went on the accelerator (but due to the design of the Plus, you still had to leave 1MB of memory on the logic board as that's the memory the Plus uses before the accelerator is initialized, as well as the video memory is located there).

One such upgrade that checks all these boxes (memory on the accelerator, internal SCSI, and included power supply) was the TurboMax from Mac Memory, which was documented in a comparison of accelerator cards in the March 1988 issue of MacUser magazine, starting on page 109. Of course, your Plus could have had a different accelerator, as there were more than MacUser reviewed in this issue.

One side note: Joe's Computer Museum sells the Clipper Plus which clips on top of the SCSI chip to provide an internal SCSI port. I've not seen a vintage equivalent, but that's not to say it wouldn't have been possible... but it would be one way to be able to plug that SCSI drive back into the Plus's SCSI bus without the accelerator card.

 

[jcm-1]

hi, thanks for the answer, it doesn't lead anywhere, I don't see any signs of modification on the motherboard. The extra power supply doesn't come with a 4-pin connector either, it's missing

Neat machine! Seems to me like it was aftermarket modded to take a SCSI hard drive, and the extra power supply may have been to provide enough extra oomph to run that internal hard drive. Those almost never happened on the Mac Plus. The Mac Plus did have mods back in the day to allow internal hard drives, but without seeing your logic board, it's hard for me to know if the mod is there but the cable is just missing. It could have had some sort of ribbon cable thing that ran from the hard drive, through the gap in the case next to the battery, then back to the DB-25 port on the machine. Who knows!

Since those mods are weird and very rare, I designed one that makes that possible. It clips right over the SCSI chip and gives you an internal hard drive port, called Clipper Plus as Justin alluded to. To be clear: it's a new thing I came up with. Nothing like my design existed when these machines were new.

Clipper Plus would allow you to use that hard drive or a replacement solid state solution like BlueSCSI (which I also sell). I would not suggest relying on the old hard drive at this point: most are already dead, and the rest will be dead soon. That's the nature of mechanical hard drives.

Clipper Plus - Internal SCSI for Macintosh Plus - Joe's Computer Museum

You have a Mac Plus. You want Internal SCSI. Clipper Plus makes that happen. Just snap the Clipper Plus over your Mac Plus SCSI chip, thread the SCSI cable up through the frame, and attach your favorite internal SCSI device. Includes internal termination power for popular SD storage devices...

jcm-1.com

BlueSCSI (v2) 50-Pin Desktop - Joe's Computer Museum

It's Faster! It's Better! It's the the BlueSCSI v2 SCSI hard drive emulator! This 50-pin internal version provides a convenient way to use SD cards as hard drives in your vintage computer. It comes as a fully assembled solution or kit! For the kit builders: We've pre-soldered all of the...

jcm-1.com

 

[moszio]

I've seen these power supply upgrades in photos, but not in person - they were part of some upgrades because the original power supplies had little margin for upgrades.

I suspect there was an accelerator card in this Mac Plus that has been removed, as normally you wouldn't be able to install an internal SCSI device due to there being no internal SCSI header. Some accelerator boards did include SCSI for an internal SCSI drive, and that hard drive could have been plugged into that. Some accelerator boards also included a supplementary power supply like the one in your Plus. And for many of these accelerator boards, upgrade memory went on the accelerator (but due to the design of the Plus, you still had to leave 1MB of memory on the logic board as that's the memory the Plus uses before the accelerator is initialized, as well as the video memory is located there).

One such upgrade that checks all these boxes (memory on the accelerator, internal SCSI, and included power supply) was the TurboMax from Mac Memory, which was documented in a comparison of accelerator cards in the March 1988 issue of MacUser magazine, starting on page 109. Of course, your Plus could have had a different accelerator, as there were more than MacUser reviewed in this issue.

One side note: Joe's Computer Museum sells the Clipper Plus which clips on top of the SCSI chip to provide an internal SCSI port. I've not seen a vintage equivalent, but that's not to say it wouldn't have been possible... but it would be one way to be able to plug that SCSI drive back into the Plus's SCSI bus without the accelerator card.

Thank you!

 

[moszio]

Neat machine! Seems to me like it was aftermarket modded to take a SCSI hard drive, and the extra power supply may have been to provide enough extra oomph to run that internal hard drive. Those almost never happened on the Mac Plus. The Mac Plus did have mods back in the day to allow internal hard drives, but without seeing your logic board, it's hard for me to know if the mod is there but the cable is just missing. It could have had some sort of ribbon cable thing that ran from the hard drive, through the gap in the case next to the battery, then back to the DB-25 port on the machine. Who knows!

Since those mods are weird and very rare, I designed one that makes that possible. It clips right over the SCSI chip and gives you an internal hard drive port, called Clipper Plus as Justin alluded to. To be clear: it's a new thing I came up with. Nothing like my design existed when these machines were new.

Clipper Plus would allow you to use that hard drive or a replacement solid state solution like BlueSCSI (which I also sell). I would not suggest relying on the old hard drive at this point: most are already dead, and the rest will be dead soon. That's the nature of mechanical hard drives.

Clipper Plus - Internal SCSI for Macintosh Plus - Joe's Computer Museum

You have a Mac Plus. You want Internal SCSI. Clipper Plus makes that happen. Just snap the Clipper Plus over your Mac Plus SCSI chip, thread the SCSI cable up through the frame, and attach your favorite internal SCSI device. Includes internal termination power for popular SD storage devices...

jcm-1.com

BlueSCSI (v2) 50-Pin Desktop - Joe's Computer Museum

It's Faster! It's Better! It's the the BlueSCSI v2 SCSI hard drive emulator! This 50-pin internal version provides a convenient way to use SD cards as hard drives in your vintage computer. It comes as a fully assembled solution or kit! For the kit builders: We've pre-soldered all of the...

jcm-1.com

Thanks for the answer. Your solution is exciting. I like it. I will take a photo of the logic board. Have a nice day!

 

[moszio]

here is the logic board ...
I just noticed that it's 4mb ram

 

[jcm-1]

Yup, that's just a plain old Mac Plus board. No SCSI mod. I'm thinking it had some sort of cable that would run from the drive, through the battery port, and down to the 25 Pin connector.

 

[moszio]

Yup, that's just a plain old Mac Plus board. No SCSI mod. I'm thinking it had some sort of cable that would run from the drive, through the battery port, and down to the 25 Pin connector.

Thanks for looking. I will look into the tools you suggested and take the time to do so. I will finish what you started
Have a nice day