Macintosh Plus: "Coprocessor Not Installed"

[dcr]

I have a Macintosh Plus and a System 6.0.8 Boot Disk (800k floppy).  This is the same boot disk I've tried unsuccessfully using on the Macintosh SE.

So, after I finished trying it in the SE again, I put the disk in the Macintosh Plus.  It started up fine.  Only a mouse was attached, no keyboard.

Then, I carried the Macintosh Plus to another room.  Then I decided I would test the keyboard I had fixed (hopefully) earlier.  Plugged in the keyboard and mouse and started it up.  Got a bomb during startup that an error had occurred and I needed to restart.  That repeated a couple times.  Thinking maybe the keyboard was causing an issue, I unplugged it.  Made no difference.

Finally, it booted but right after displaying the menu and the disk icon (but before displaying the trash icon), it bombed with a system error, saying "coprocessor not installed."  Tried rebooting a couple times, but it made no difference.  With or without the keyboard, no difference.

It's the same disk that worked earlier in the day.  Not sure what the problem could be.  Is it a disk problem?  Or a problem with the Macintosh Plus?

The disk was formatted on a Quadra 800 running system 7.  Mac OS Standard file system, not Mac OS Extended.

 

[Byrd]

Definitely try another boot disk, and potentially clean the heads and drive mechanism on the Plus.

 

[bibilit]

The problem is you tried the disk on the SE first, and the dirty heads of the SE probably made the disk bad.

 

[dcr]

Just a follow-up note on this . . .

Since reformatting and re-copying the boot disk, I was able to boot the Mac Plus with the floppy disk without a problem.  The same disk was used when I booted the Mac SE from the Mac Plus's floppy drive.

I have not tried booting the Mac Plus multiple times with the disk but I am guessing it appears bibilit was correct and it was the SE's apparently defective floppy drive that corrupted something on the floppy disk to cause the error on the Mac Plus.

Haven't done anything as far as cleaning the floppy drive in the Mac Plus, but when I opened the Mac Plus to remove the floppy drive to temporarily install it in the SE, I found the Mac Plus needs a lot more than a floppy drive cleaning!

 

[Sherry Haibara]

Just be careful while cleaning the floppy drive, it's easy to bend the heads and make the whole thing a nice but useless doorstop. Killed a couple this way!