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TABLE 2-2.
OFF LINE TESTER SWITCH FUNCTIONS
(CONT'O)
switch/Indicator
DATA SYNC JACK
(Rear of Tester)
Mode Select
Switch Position
3. Set ON LINE/NORMAL/WRITE DISABLE switch
to OFF LINE (normal).
Tester will not
work in ON LINE mode.
If operated in
WRITE PROTECT mode, accessing and read-
ing are normal, but data cannot be
written.
4. Open tester bottom panel and remove cable
assembly.
If tester has not been used,
verify that 12.88 MHz crystal is instal-
led.
The 13.60 MHz crystal should
be
in
the dummy jack.
Replace cover.
NOTE
DC power supply voltage must be
removed when tester is being in-
stalled or removed.
5. Connect cable assembly between connec-
tors on rear of tester and C27 on logic
rack.
Tester receives power from drive.
Set START/STOP switch to STOP.
6.
Apply DC power.
OPERATING PROCEDURES
Error Detedion
The DISPLAY SELECT switch on the logic rack
maintenance panel is a valuable accessory in
using the tester.
A thorough knowledge of
this switch and its functions will assist
greatly in isolating malfunctions.
Functions
of each switch position are specified in
Table 2-1.
When the DISPLAY SELECT switch is set to
ADDRESS VERIFY position, the ADDRESS
&
CON-
TROL BUS indicators display the cylinder
address read from the disk.
This function
is enabled only during tester read operations.
If any error occurs, all accessing stops and
the last address read will
be
displayed.
Proceed as follows:
1.
Set DISPLAJ SELECT switch to following
posiiton to verify the type of error.
DSB4, Bit
2 6
displayed indicates that
the tester detected an address error:
DSB3, Bit
27
indicates a seek error; etc.
(refer to Table 3-3).
83318200
C
Function
Provides scope sync point during read opera-
tions.
Signal is positive-going at begin-
ning of data pattern (which follows cylinder
byte) and drops at end of data field.
Be-
cause of timing variations and propagation
delays between tester, drive, and scope, the
first bit of the data pattern may not actua-
ally be displayed.
2. Set switch to CYLINDER position to de-
termine the address that the drive
should be at.
3. Set switch to DIFFERENCE position to
check the contents of the difference
counter.
When the seek is completed,
all bits should be on (which is the
complement of zero).
4. If the cylinder and difference are
correct, but an address error is
indicated, proceed as follows:
a. Press FAULT switch.
Address Error
DSB4 2
6
is stored in drive's Fault
register.
FAULT switch must be
pressed to clear that bit.
b. Select R/W ONLY.
c. Reread cylinder address.
d. If ADDRESS VERIFY display matches
CYLINDER display, the error is not
a positioning error; a read error
caused the previous "address error".
5.
If CYLINDER and ADDRESS VERIFY cannot
be matched, cause of the address error
was a positioning error.
While performing sequential forward seeks,
and with the DISPLAY SELECT switch set to
CYLINDER, the display will increment with
e:lch seek.
Seek Operations
The tester is capable of performing the
following seek operations:
•
Single seek to any cylinder
•
Repeated seek between any two cylinders
•
Sequential seeks at selectable seek
lengths
NOTE
Do not exceed seek lengths greater
than 25Srtracks.
•
Random cylinder seeks
2-11
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