Tension Posts; Suggested Method Of Adjusting Brake Torque - Scully 280B Series Instruction And Maintenance Manual

Model 280B
Maintenance
38-46 OZ.
NOTE: NAB TYPE A REELS
9
--f - I-~-----I-
1/4 & 1/2"
=
19-23 OZ
1""'= 28-330Z
_ 1 - - - ­
r
Figure 7-2. Suggested Method of Adjusting Brake Torque
1 to 1.5 degrees is ideal. Adjust the scrape fil ­
ter by loosening the rotation adjustment screw
(6) and carefully positioning the filter for cor ­
rect tape contact.
E. The erase, record, and playback head assem ­
blies can be removed from the head bridge
mounting plate (3) by unscrewing the 10-32
socket-head cap screws (7) and unplugging the
head connectors. The individual stacks can be
removed from their respective mounting
blocks by loosening the 6-32 azimuth screws
(5). The entire head/bridge assembly can be
removed for inspection by unplugging the
head cables and removing the three 8-32 flat ­
head screws (2) that hold the head bridge
mounting plate. No realignment
is
required
upon reinstallation when neither the azimuth
nor zenith adjustment has been changed.
7.4 Motion-Direction Sense Adjustment (Fig. 7-4)
A. Loosen two screws (14) and adjust motion
direction sensor PWA so that motion direction
sensor arm assembly (9) is centered in the slot
of the photon coupler on the PW A .
B. Connect a voltmeter, using the 0 to 5 Vdc
minimum range, between ground a Ul-l on
the transport logic PWA (Figure 8-32). Loosen
two screws (18) on motion direction sensor
bracket (4). Hold reel knob on supply motor
and rotate it back and forth slightly. Position
the motion direction sensor bracket until the
voltage switches from 0 to 3.5V minimum in
the forward direction and from 3.5 V mini ­
mum to OV in the rewind direction (OV
=
Logic 0, 3.5V
=
Logic 1). When the motion
direction sensor bracket is correctly adjusted,
the reel knob will move equal amounts in
each direction before the voltmeter needle
starts to move.
7.5 Tension Posts (Figure 7-5)
To adjust the tension post spring on the tape break
arm, loosen the setscrew (2) on the spring adjust­
ment collar (1) and rotate the collar to increase or
decrease tension.
NOTE
The tape break
arm
has two adjustment
collars. Be sure to loosen the setscrew
in the round collar (1), not the one
in the collar with the flat (4).
This adjustment can be made from the underside
of the transport, and is normally optimized for
best tape handling. The tape break arm should be
set
to
operate the microswitch (3) approximately
0.125 to 0.25 inch (3.18 to 6.35 mm) before the
7-3