Tandon TM100-1 Operating And Service Manual page 54

2
FIGURE 5-12
HEAD AZIMUTH ALIGNMENT
OF ACCEPTABLE UPPER LIMITS
5.9 TRACK 0 SWITCH CHECK
AND ADJUSTMENT
The Track 0 switch circuitry provides a signal
identifying Track 0 to the logic electronics. The
electronics disable the step-out function when
Track 0 is reached. In addition, a Track 0 signal
is sent to the controller on Pin 26 of the inter­
face. If the Track 0 switch cannot be adjusted,
refer to the troubleshooting guide.
TRACK 0 SW ITCH CHECK
1 . Set up the oscilloscope:
Channel A: Test Point 1
Channel B: Test Point 2
Ground: Test Point 10
Read Differentially: A plus B, B inverted
Time Base: 20 milliseconds per division
External Trigger: Test Point 7 , positive
edge
Vertical Display: 0.1 volt per division
2 . Apply power to the drive.
3 . Insert a Cats Eye alignment diskette
into the drive.
4 . Close the front latch.
5 . Step the carriage to the radial alignment
track.
6 . Confirm the position by observing the
Cats Eye pattern.
7 . Set up the oscilloscope to monitor the
TTL signal at IC 4B, Pin 9, or at P ll, Pin
2
.
8 . Step the carriage back to Track 1 .
9 . Ensure the signal at Track 1 is at least
2.5 volts.
10. Step the carriage out to the radial align­
ment track.
1 1 . Step the carriage back to Track 2 .
1 2 . Verify the logic level at IC 4B, Pin 9 , is
less than 0.8 volt.
13. If all of these checks are satisfactory, no
adjustment is required.
14. If any of these checks is unsatisfactory,
adjust the Track 0 switch.
TRACK 0 SWITCH ADJUSTMENT
1 . Loosen the retaining screw on the base of
the Track 0 bracket.
2 . Retighten the screw slightly to provide
some friction on the bracket.
3 . Rotate the Track 0 adjustment screw, at
the rear of the chassis, counterclockwise
as far as it will go without forcing it.
4 . Step the carriage back from the radial
alignment track to Track 1 , but do not re­
store it to Track 0 .
5 . Rotate the Track 0 adjustment screw
clockwise, very slowly, until the signal at
IC 4B, Pin 9 , is at least 2.5 volts at Track
1 and less than 0.8 volt at Track 2 .
6 . Retighten the retaining screw.
7 . Repeat the Track 0 Switch check to
ensure the correct setting has been
attained.
5-12