Sony DNW-A220 Maintenance Manual page 149

Setting of Head Tip Protrusion Measurement
Gauge
n
Being careful not to damage the tape-running surface and
video heads of the drum, set the gauge.
1. While pushing the manual eject knob downward, turn
it clockwise to set the unit in threading-end condition.
n
Make sure that the T drawer arm hits the stopper at
this time.
2. Rotate the upper drum manually counterclockwise (3)
to align the label of the board cover with the frame of
the brush assembly.
n
The upper drum position is determined as described above
to put the probe of the head tip protrusion measurement
gauge on the absence of a head. The video head that first
measures the protrusion value is the CNF A head.
3. Check the value that the dial gauge pointer reads.
4. Position a probe between the dummy head and CNF A
head. (Refer to Figure 2.)
5. Press the tip of two legs against the outer circumfer-
ence of the drum's upper surface while keeping the
base plate of the measurement gauge in parallel with
the upper surface of the drum. Be sure to keep the
probe of the measurement gauge sufficiently away
from the drum.
6. Lower the measurement gauge slowly until the ridges
of the two legs and positioning flange touch the upper
drum while pushing two legs against the outer circum-
ference of the drum's upper surface (applying force
slightly to the measurement gauge in the direction
indicated by the arrow). (Refer to Figure 3.)
m
. Before placing a measurement gauge on the drum,
ensure that the adjustment screw has been loosened
fully.
. Perform carefully and slowly so that the probe of a
measurement gauge does not touch the outer circum-
ference or video head on the drum.
(Lower so that the probe is slightly higher than the
two legs.)
. After placing the measurement gauge on the drum,
be sure to support it with hand at all times.
If it is loose carelessly, the drum and measurement
gauge will turn and damage the peripheral parts.
DNW-A220
DNW-A220P
Brush assembly
Label
Board cover Dummy head
CNF A head
Figure 2. Alighment of Drum Position
Head protrusion measurement gauge
Base plate
Leg
Cover
Leg
Drum
Figure 3. Setting of Head Tip Protrusion Measurement Gauge
4-4. Video Head Tip Protrusion Check
Manual eject knob
Stopper
T drawer arm
Adjustment screw
Dial gauge
A
A
Positioning
frange
Drum
Probe
4-11