Specifications

5/2/2013 888-2500-001 5-19
WARNING: Disconnect primary power prior to servicing.
Section 5 Maintenance and Alignments
DAX-1/DAX-3
STEP 4 Remove the yellow wires from the power supply terminals
STEP 5 Unscrew the 2 fasteners holding the mounting plate to the wall
STEP 6 Unscrew the power supply to be replaced from the plate
STEP 7 Mount new power supply to plate with the screws from STEP 6
STEP 8 Mount plate to wall with the 2 fasteners from STEP 5
STEP 9 Re-attach yellow wires to corresponding terminals noted
STEP 10 Reconnect primary power to the transmitter
STEP 11 Turn on CB1
STEP 12 Press the METER button and then the up or down arrows to navigate to
the below screen
Figure 5-6 Meter Screen
STEP 13 On the replaced power supply, adjust the potentiometer next to green
LED and wire terminal on the top of the power supply for a correct
voltage (±5%) reading on this screen
STEP 14 Turn DAX transmitter on and observe for correct operation
5.6.4 PA MOSFET
Typically, a MOSFET device will fail as a short circuit. This can be detected by reading
the resistance, in-circuit, between the Gate and the Source with an Ohmmeter: A
reading of less than 100 Ohms indicates a failed MOSFET.
If it has been determined that a pair or more of MOSFETs needs to be replaced, special
attention should be paid to the following issues:
• Ferrite bead location and size: Please note there are 3 different sized beads strategi-
cally installed on certain MOSFET leads. Be sure to replace the correct bead back on
the correct lead of the correct MOSFET before soldering.
• Insulator must be replaced: There is a small insulator between the MOSFET and
the heatsink. It may be easy to overlook or misplace. These insulators should be
replaced by new when replacing MOSFETs.