Specifications

measured on the output pin of U1. If the relay is to be de-ener-
gized, the Bit input must be an open circuit and should therefore
measure +24VDC.
D.5.2
Relay Ohmmeter Testing
Relays may be ohmmeter tested using a power supply, by apply-
ing +24VDC to the + pin 1 input and ground to the - pin 2 input.
The relay should make a “clicking” sound when energizing. The
contacts can also be checked for open/closed continuity.
D.5.3
Visual Inspection
With the assembly removed, visually inspect the tapped inductor
connections and the capacitor mounting hardware for loose
contacts.
D.6 Removal\Replacement
WARNING
ENSURE THAT THE TRANSMITTER IS TURNED OFF AND ALL
PRIMARY POWER IS TURNED OFF AT THE WALL DISCONNECT
SWITCH BEFORE OPENING ANY DOOR OR PANEL. BEFORE
REMOVING PANELS OR OPENING DOORS, VERIFY THAT THE
RF AMP POWER SUPPLY IS DISCHARGED BY CHECKING
“PA+VDC” ON THE FRONT PANEL MULTIMETER. USE A VOLT-
METER TO VERIFY THE POWER SUPPLIES HAVE BEEN DIS-
CHARGED PRIOR TO TOUCHING ANY COMPONENTS.
NOTE
The Predriver Tuning board is mounted to a metal angle bracket
assembly that is held in place by 3 screws.
Remove all connectors and the single front screw from the inside
of the right PA compartment. Remove the 2 remaining screws
from the rear of the transmitter and lift out the assembly from
behind. Remove connections from TB1.
When installing a new board, verify that all jumpers on the new
board are in the same position as the jumpers on the original
board.
D.7 Alignment
There are no alignments on this board.
The board is factory tuned and should not require readjustment.
However if mistuning of the Predriver is suspected, operate at
1600 kHz and adjust Predriver Tuning L1 for a peak in Predriver
current as indicated on the Drive Multimeter.
D-2 888-2339-002
WARNING: Disconnect primary power prior to servicing.