Index Checks And Adjustment; Index Checks; Index-To-Data Pulse - Tandon TM-100-1 Operating And Service Manual

2.3 INDEX CHECKS AND ADJUSTMENT
The index adjustment changes the time period from the index pulse to the start of the data. The adjustment
should be checked after the disk drive has been aligned (see Section 2.1.1) or when diskette interchange errors
are suspected.
2.3.1 Index Checks
2.3.1.1 Check the speed of the long-term drive motor.
2.3.1.2 Apply power to the disk drive.
2.3.1 .3 Select the disk drive with the control logic.
2.3.1.4 Set up a dual-channel, wideband oscilloscope, as follows:
External Trigger: Test Point 7, Positive Edge
Read Differentially: A plus B, B inverted
Channel A to Test Point 1
Channel B to Test Point 2
Time Base: 50 usec Per Division
2.3.1.5 Insert an alignment diskette.
2.3.1.6 Select Track 01.
2.3.1. 7 Select Head 00, the lower magnetic head.
2.3.1.8 Read the trigger point to the start of the first data pulse width (see Figure 2-8).
NOTE
The specification is 200 usec ± 100 usec.
:
I
~
"
I
I \
M
V
:
:
TIME SCALE: 50 USEC PER DIVISION
Figure 2-8
Index-To-Data Pulse
2-8