WARNING! DANGER OF INJURY. IF THE BRAKE RELEASE SWITCH IS
INADVERTENTLY MOVED TO THE PITCH POSITION THE
RADAR ASSEMBLY IS LIABLE TO TOPPLE TO ITS MECHANI-
CAL LIMITS.
19 Apply the roll frame brakes by pulling on and moving the brake release
switch to the central position. Do not remove the roll turnbuckle at this
stage.
20 Disconnect the digital multimeter from the cable connector, and reconnect
cable to connector SKT on the SAP Management Unit (see fig. 3.23 (p. 56))
21 To be able to move the SAP in pitch direction, mount the pitch part of the
jacking kit (jacking brackets and turnbuckle) according to the procedure
described in task “PMA03: Manually moving the Antenna System” (p. 42).
22 Disconnect cable from connector SKR on the SAP Management Unit (see
fig. 3.25).
23 Connect a digital multimeter across
pins A and B of the disconnected
cable connector, and measure the
resistance. This is the resistance of
the pitch limit switch on the aft side of
the SAP i.e. in the clockwise direction
(with respect to the port side of the
SAP) of pitch frame movement. This
resistance should be less than 2.5
Ohms. If it is more than this, seek
advice from the manufacturer, before
continuing this procedure.
24 Release the pitch frame brakes by pulling on and moving the brake release
switch to the PITCH position.
25 Use the pitch turnbuckle to slowly angle the pitch frame towards aft until the
limit switch operates. Do not move the pitch frame any further, because it is now at the activation angle of the limit switch. The resistance displayed on the digital multimeter, should be greater than 20 MOhms. If it is less, seek advice from the manufacturer, before continuing this procedure.
26 The activation angle, displayed on the hyperterminal, should be between
12.5ฐ and 13.5ฐ towards aft (i.e. 12.5บ nominal, tolerance -0.0บ to +1.0บ). If it is not, it is necessary to adjust the limit switch mechanism as follows, to bring the activation angle within this range (see fig. 3.24 (p. 56)):
• Use the pitch turnbuckle to angle the pitch frame back towards forward,
until the limit switch deactivates.
• Adjust the limit switch mechanism in such a way as to bring the activa-
tion angle within range (or at a point nearer to being within range).