Write Splice Bit To Index Timing - Control Data Corporation BR8 SERIES Hardware Maintenance Manual

d. -contd.
Chan 1 voltage to: AC
Chan 2 voltage to: AC
Source to: Chan 1
Coupling to: Low Freq.
(Hi Freq. Reject)
Vert. Mode to: Add
Slope (Sync) to: Pos.
Trig. Mode to:· Normal
Time Base to: 50us/div
e. Adjust the time from write splice bit to the leading edge of the index pulse until it
Ineasures per Table 6-2. (Refer to Figure 6-7 to adjust the write splice to index
time, loosen the A.llen head screw holding the phototransistor located on bottom
of chassis toward the front of the unit.) Using the adjustment handle protruding
through the casting, move the phototransistor until the specification is met. Tighten
the A.l1enscrew while observing the
sc~pe
signal. Verify that the adjustment did not
change. If the adjustment cannot be achieved, it may be necessary to adjust the
LED sensor located on the top plate assembly.
f. After the adjustment has been made and specification met, change the scope time
base to
o.
5ms/div and verify that the index pulse width measures 1. 5 ±O. 7ms
(from
o.
8ms to 2. 2ms). If the index pulse width is not within specification, adjust
the LED sensor located onthe top plate assembly. If the pulse width cannot be
adjusted to meet specification, the sensor assembly or PWA must be replaced
and steps "a" through "f" repeated.
g. A.ll scope settings are to remain as defined in the original setup in step "d", but it
may be necessary to slightly adjust the sync. Seekto track 00 then seek to track 1
and perform a read. While observing the signal on the signal ont he scope, remove
and reinsert the diskette three times.
After each insertion, verify that the change in the time from write splice to leading
edge of index is less than 50 us. If the change is greater than 50 us, the cone and
spindle must be aligned or replaced (see section 6.6.7) and steps "a"through
"g"
repeated.
~~------------------~
:
~I
I
I
I,.
WRITE SPLICE ADJUSTMENT
1
1
"-1
(See Table 6-2)
1 :
Figure 6-7. Write Splice Bit to Index Timing
Table 6-2. Write Splice Adjustment
CONFIG. REF. NO. WRITE SPLICE ADJ. QIS)
601 450 ±50
602
150 ±60
603 450 ~!::100
6-20
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