Zeroing the roller with the rate mechanism
RESTRICTED
7. Zero
Ground
Speed
Drum
washer rests against the spindle gear and then
го-
tate nut gear 2 teeth
movement so that the spind-
le screw is translated upward.
B. ZERO THE ROLLER WITH THE RATE MECHANISM.
1. Clamp T.A. at
zero.
2. Replace rate end and
remove displacement knob
plate.
3.
Start telescope motor and set in maximum disc
speed.
4.
Move roller with rate mechanism until the
roller stops rotating.
At this point the roller
is roughly zeroed, so
it is necessary to proceed
to the third step to find exact zero position.
at this point the rate indicator is off
zero, it will be necessary to remove the three
screws
which hold the rate rack pinion gear in
mesh with the rate rack and remesh it when the
rate indicator has been
restored
to zero.
Do not
disturb the position of the roller or
the T.A.
This procedure will be necessary only if the orig-
inal factory meshing
relationship has been dis-
turbed.
ZERO THE ROLLER BY DIVIDING BACKLASH.
At the center of the disc there
a "dead"
area of 1 1/2 to 2 mils in diameter, i.e. when the
roller reaches either the upper or
lower extremity
of this area it will stop rotating.
Therefore
the rate mechanism cannot alone be
uced to find
exact center of the disc.
1.
Loosen T.A. from
shaft,
and unclamp from trail
plate;
slip T.A. to
approximately 20 mils.
(B€
careful not to disturb
nut gear).
Clamp T.A. and
trail plate, clamp
T. A.
to shaft.
Set maximum disc speed and turn telescope
motor
"on"
3.
Move T.A. to maximum trail setting and then
slowly back toward zero.
When roller stops turn=
ing mark
position.
Repeat in opposite direction.
4.
Position T.A. between two marks and clamp to
trail plate.
Unclamo
T.A. from shaft and slip it to zero.
Rec lamp.
Recheck.
So long as the rate rack pinion gear is not
remeshed during
the process of zeroing the
roller,
if the ground
speed
drum were at zero with the
rate quadrant at zero, it will not be necessary to
*e-zero
the
ground speed drum
after zeroing the
roller.
NOTE:
C.
is
2.
5.
160