Read Data: Test Points 3 And 4; Track 0: Test Point 5; Index Sensor: Test Point 6; Field Accessible Components - Seagate ST212 Product Manual

9.2.2 READ DATA: TEST POINTS 3 AND 4
These points may be used to monitor Read data from the operation of the time
domain filter. liigger off test point 4 and monitor the delay at test point 3. Typi-
cally, a 120 nsee. delay will be observed. A full track record of high frequency
data (0000 or 1111) will resemble Figure 33.
FIGURE 33:
Read Data
Test Point 4
Raw Data
Test Point 3
Delayed Data
9.2.3
TRACK 0: TEST POINT 5
The lfack 0 sensor may be monitored at lèst Point 5. A high logic level indi-
cates valid Track 0. The stepper motor must be at Phase A and the Read/Write
heads at Cylinder Zero before a valid lfack 0 signal will be issued.
9.2.4
INDEX SENSOR: TEST POINT 6
Test point 6 may be used to monitor the Index Sensor. Only the leading edge
of the pulse is valid. A typical signal will resemble Figure 3J.
Test point 6 is used to monitor the spindle motor during speed adjustment. Ad-
just at R3 (MLC-OO, access through the side of the frame) for a period of
16.67 msec. ±IOJo.
9.3
FIELD ACCESSIBLE COMPONENTS
The procedures covered in this section may be completed without special tools
or cleanroom facilities. There are no user-serviceable components inside the
head/disc assembly (RDA). The RDA is sealed and Seagate will consider a drive
to be out of warranty if the seal is broken.
36 ST212 PRODUCT MANUAL/Rev. B