Hi All,
My first post!
I have an original Mac 128k with external 400k drives.
In fact I two external 400k drives (Sony OA-D34V-22). Obviously, I can only use one at a time on this Mac. One of them works fine, the other has an issue. Maybe someone can assist me to debug it.
I cleaned and lubricated both drives so the "mechanics" work fine (load, eject, etc.).
One drive works well. I can read disks, even boot off a disk that has an operating system.
If I try to boot off the other external drive, the Happy Mac initially appears, followed by a Sad Mac (0F0064).
If I boot off the internal drive, and then insert a disk in the "bad" external drive, a message appears "that the disk is unreadable" and gives me the option to format it.
I hooked an oscilloscope to the Read pin of both drives when they are operating (pin 6 of the Sony). I see there is a signal as the head moves about on the disk. In fact, both drives behave similarly. Here's a typical screenshot of the oscilloscope trace. I've read that typical Read traces show approximately 0.5 microsecond pulses (corresponding to the bits recorded).
So, both drives appear to read the disks and generate signals for the computer.
Anyone have a suggestion as to why one drive doesn't work properly with the Mac?
I also added a picture of the ROMs of the Mac.
Michel
My first post!
I have an original Mac 128k with external 400k drives.
In fact I two external 400k drives (Sony OA-D34V-22). Obviously, I can only use one at a time on this Mac. One of them works fine, the other has an issue. Maybe someone can assist me to debug it.
I cleaned and lubricated both drives so the "mechanics" work fine (load, eject, etc.).
One drive works well. I can read disks, even boot off a disk that has an operating system.
If I try to boot off the other external drive, the Happy Mac initially appears, followed by a Sad Mac (0F0064).
If I boot off the internal drive, and then insert a disk in the "bad" external drive, a message appears "that the disk is unreadable" and gives me the option to format it.
I hooked an oscilloscope to the Read pin of both drives when they are operating (pin 6 of the Sony). I see there is a signal as the head moves about on the disk. In fact, both drives behave similarly. Here's a typical screenshot of the oscilloscope trace. I've read that typical Read traces show approximately 0.5 microsecond pulses (corresponding to the bits recorded).
So, both drives appear to read the disks and generate signals for the computer.
Anyone have a suggestion as to why one drive doesn't work properly with the Mac?
I also added a picture of the ROMs of the Mac.
Michel