Zenith Z-100 PC series Service Manual page 291

Page
4.5
Troubleshooting
2. On normal powerup, the message:
+ + +
DISK
ERROR:
Seek failure!
+ + +
can result from the disk drives not being plugged into the controller
card or not receiving the correct power supply voltages. After having
the computer off for at least five seconds, turn it back on and watch
the drive access indicators. If they momentarily come on, then the
drive is probably receiving the correct power supply voltages and
signals from the floppy disk controller. Make the next check.
3. On normal power up, the messages:
+ + +
DISK
ERROR:
Invalid address mark detected!
+ + +
+ + +
DISK
ERROR:
Sector not found!
+ + +
+ + +
DISK
ERROR:
Seek failure!
+ + +
+ + +
DISK
ERROR: eRe
error!
+ + +
or no error message at all (but the system is attempting to boot
a disk) can indicate a bad or unformatted disk, wrong format (CP/M
instead of MS-DOS), or wrong operating system (Z-DOS instead
of MS-DOS). The "sector not found" error message also may indi ­
cate a data disk (non-bootable disk).
In any of these cases, reset the computer (you will probably have
to turn it off, wait five seconds, and then turn it back on), and attempt
to boot the system with a known good disk. Do not use distribution
disks for this purpose; use a backup.
4. The message:
System disk
indicates that the disk has the correct format, but not an operating
system.
5. If you are servicing the computer with the drives out, make sure
that all parts are free to move normally. Do not lay the drive flat
on top of the power supply. The magnetic flux fields can interfere
with normal disk movement and cause the "seek failure" error mes­
sage, even with a good disk. Also, the magnetic flux fields can erase
enough information to cause intermittent conditions with a good disk.