(4) Write Input/Output
1) Write Clock and N RZ Input Data
2) MFM Data
DWD Output (1)
: : s
Normal, Late- Same with Clock Bit
DWD Output 2
. . .
Precompensation Mode at EXT
- - - . .
Trouble analysis of the NDC5801 Hard Disk Controller is
described, sequence by sequence.
The tools necessary for trouble analysis are the following
(1) Host system (MZ-6500)
(2) Troubled 5" Disk and NDC5801 controller
(4) Test program
6" D l S K
6-4-2. Self-Diagnostic Function
This function works with the power on. A judgement of
good or bad is shown with the SELECT LAMP of the drive
and the LED of this controller.
(1) SELECT LAMP
The normal action of this lamp after the power is
turned on is to light in twenty seconds then immediate·
ly go off. Abnormal cases include the following.
If the spindle motor of the dirve does not
the drive is bad or the power system of the drive is
llf the lamp does not light after the controller is
exchanged, the drive or the cable between the dirve
and controller is bad. If the lamp lights, the Drive
Select of the controller
If the red LED remains lighted after the power is
turned on, the Dirve Select of the controller is bad.
If the red LED finally lights though the green LED
lighted up once, change the controller and recheck
After the exchange, if the green LED lights, this indica-
tes that the controller is bad. If the status remains the
same, then the drive or the periphery is bad