IBM System/34 Maintenance Manual page 406

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2.
3.
4.
5.
6.
Set the Address/Data switches to FSOO (CE panel)
and perform an IPL.
Select the EXERCISERS option from the main
menu.
Select the DISKETTE DRIVE option from the first
exerciser menu.
Select the DISKETTE EXERCISER LOAD MODULE
option from the second exerciser menu.
Select an orient carriage, select diskette from slot
3, recalibrate, and for this example, a seek to
cylinder 24 from the diskette exerciser test 1
command menu (enter an E after selecting the
cylinder number).
7.
Use the default option to execute the commands.
S.
9.
Press the Attn key (three times) to return to the
diskette exerciser test 1 command menu.
Select the READ LOOP command and, for this
example, select MFM mode, cylinder 24, head 1,
sector length
=
256, sector 11, and M/S data field
1 from the displays (enter an E after selecting the
sector number).
10. Select the LOOP ON CMND TABLE option and,
for this example, set the Address/Data switches
(CE panel) to
0093
to display byte
93.
The loss of amplitude can be seen on the oscilloscope.
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Example 2: To scope a damaged track, the following
changes must be made to the preceding procedure:
1.
2.
3.
4.
5.
Set the Times Per Division on the oscilloscope to
10 ms/cm.
Connect the trigger to the +index test pin (TPB-14
for machines with the old style picker, TPB-16 for
machines with the new style picker).
In step 6 of example 1, seek to the damaged
cylinder.
In step 9 of example 1, select the READ 1
SECTOR ON CURRENT CYL command (select the
data field, and cylinder number that you want to
scope).
In step 10 of example 1, select the SCOPE LOOP
A CMND option.
The following oscilloscope screen image shows the
damaged area of the diskette.
1 Track
Damaged Area
27-940
72MD Diskette Magazine Drive 121
-