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Upgraded 'original' Macintosh

Juror22

Well-known member
This weekend I opened a double-wrapped box that came to me by way of PowerFlute and I unpacked an original Mac.  Since my previous oldest Mac was a 512, I had been on the lookout for a reasonably priced example.  This one has a beautiful, un-yellowed case, and a MacBCool topper that provides both power and cooling.  I powered it up and it booted with a nice startup chime to a perfect screen - it even came with a programmer's switch, plugged into the side.

Since it came without a keyboard or mouse, I dug those items out of my den (I couldn't locate the keyboard cable - need to find that), along with a 400K startup disk that I last used on my 512K.  With the system 3.2 disk and the mouse plugged in, I restarted it and it came up nicely.  When I checked the 'About this Finder' and it listed 512MB, it was not unexpected and I was both relieved and disappointed that it was an upgraded version.  I would have liked to get an all original unit, but on the other hand it would be nice to actually use it for more than "Ooooh, it boots and runs MacPaint".

Shutting it down resulted in it keeping the disk (no eject) and rebooting.  So, it looks like at the very least I need to open it up and check out the insides and lubricate the drive.  So, I opened it up (super clean inside with minimal grime) and it appears to have an original board (see pics) that is upgraded to 512MB and also has some newer ROMs added.  But the fun does not stop there, the drive that I take out is a Sony MP-F51 (800K) drive.  I disassembled and re-greased the drive, reinstalling it and the motherboard.  The drive doesn't try to eject, rather, it doesn't seem to get signaled to eject.  Checking out this post from 2015 seems to explain the issue, although my situation (drive, ROM's and system disk are a bit different, I think the same issue applies).

So, is ejecting disks going to be an issue until I source a 400K drive to throw in it, or is there another issue going on, that can perhaps be addressed?

Mac128-03.JPGMac128-04.JPG

 
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unity

Well-known member
The drive might have the wrong cable. 400k drive is red, 800k is yellow then back to red for the 1.4. And you have a red cable. The other possibility is damaged drive gear. But I would source a proper cable first.

Looks like a mid-year unit or its has some service upgrades, that logic board cable is the latest version. If earlier unit, might have been swapped during upgrades. For downgrading, I would not bother with the RAM. Its pretty useless with 128k. But its doable. The drive downgrade would be a lot easier and if you leave the ROMs in place I *think* you can use an 800k external if needed.

 

Gorgonops

Moderator
Staff member
 When I checked the 'About this Finder' and it listed 512MB
That's pretty impressive, considering the 68000 CPU only supports 24 bit addressing. ;)

Regarding the drive, I'm not sure what the point of downgrading it to a 400k drive would be. Looking at the part numbers on the ROMs you've currently got the equivalent of a Mac 512ke. (IE, a 512k with Plus ROMs, apropos for an 800k drive.) Are you *positive* the drive itself isn't having some issues? Do you have another older 800K drive you can try swapping in, or can you try the mechanism from this machine in another box? Honestly, digging through that old thread it sort of comes across to me that ultimately the problem was bad drives.

 

Juror22

Well-known member
I have a MacPlus that works well and is easily accessible, so I will check out the drive and cable and go from there.

Thanks for the advice and suggestions - I checked the text at least a couple times, I can't believe that I put down MB instead of KB, but there it is...nice catch.

 
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