Teac A-3440 - Measurement and Adjustment - Mechanical; Pinch Roller Pressure Check; Brake Torque Measurement

7. MEASUREMENT AND ADJUSTMENT
— MECHANICAL —
7-1 PINCH ROLLER PRESSURE CHECK
NOTE: Pinch roller pressure is supplied by the pinch roller
N=
12
spring arms and it is most important that the sole-
noid plungers be fully bottomed before taking
pressure measurements.
. Load tape or block the shut-off arm in the ON position.
. Attach a suitable spring scale to the pinch roller shaft.
. Place the deck in the Play ( > ) mode, and holding the
spring scale as illustrated, slowly draw it away from the
pinch roller.
. Do not allow the spring to rub against the pinch roller.
. Note the reading on the spring scale at the instant the
pinch roller stops rotating.
. The scale should indicate 2.1 to 2.3 kg (4.6 to 6.0 Ibs).
. If adjustment is necessary, loosen the 3 screws on the
capstan solenoid and position the solenoid for optimum
pressure.
. Adjust solenoid-limit position so that the gap between
capstan shaft and pinch roller is approx. 6 mm when
solenoid is not actuated. Also make sure pinch roller
shaft does not contact Spring Arm (B). Limit is adjusted
by loosening the mounting screw (A), then sliding until
proper position is obtained.
Mounting Screws(A)
Capstan Solenoid
Reposition Solenoid to
Obtain Optimum Pressure
Capstan
Shaft
Fig.7-1 Pressure Measurement and Adj. Location
7-2 BRAKE TORQUE MEASUREMENT
Brake torque measurement is made with Power OFF.
NOTE: The brake torque is actuated mechanically.
Torque is set by the variable leaf spring force.
While making these measurements and adjustments,
be careful not to be bent the brake bands.
Preliminary Adjustments
1.
Loosen the screws marked (A) and (B) in the figure and
then push the solenoid plunger until it is fully bottomed
in the solenoid. At this time adjust the brake solenoid
for minimum clearance between Brake Arm and Solenoid
Plunger. Then tighten four screws (B). Then, while the
plunger is fully bottomed, adjust the position of the
Brake Band Space Ass’y so that there is a clearance be-
tween the Brake Band and the surface of the Brake
Drum. Then tighten two screws (A).
Fine Adjustment
2.
Piace an empty large hub reel on the left reel table, and
fasten one end of a 30” length of string to the reel an-
chor.
. Wind serveral turns of string counter clockwise around
the hub and attach a suitable spring scale to the free end
of the string.
. Pull on the spring scale and take a reading only when the
reel is in steady motion since the force required to over-
come static friction will produce a false, excessively high
initial reading.
. The reading should be 1600 to 2000 g-cm (22.4 to 28.0
oz-inch).
. If adjustment is required, loosen the 3 screws marked (C)
shown and position the brake for optimum pressure.
. The adjustment of the right brake is the same with the
exception that rotations are clockwise. (Wind string
Clockwise around reel hub).
Brake Band Space Adj.(A) Brake Torque Adj. Screws (C)
' Brake Solenoid Stroke Adj. (B)
Fig. 7-2 Brake Torque Measurement and Adj. Locations