Operating instructions

DMH Series VHF Radio Maintenance
BK RADIO Page 5-7
5.4.4 PA ASSEMBLY
A. Using a 7/16" deepwell socket, remove the hex nut from the antenna connector on the
back of the heatsink housing.
B. Remove the 13 screws from the PA board.
C. Remove the PA board from the heatsink housing by pushing the power connector and
antenna connector.
D. Remove the Accessory board by removing the one screw on the back.
NOTE: During reassembly, press the heatsink housing evenly against the Core assembly
while inserting the 4 screws. Tighten screws at diagonal corners to seat the
heatsink housing firmly. Install the remaining screws.
5.4.5 UNIT ASSEMBLY
To assemble the unit, complete the disassembly procedure in reverse order.
5.5 ALIGNMENT PROCEDURES
The DMH radio uses all electronic tuning with no manual adjustments. Use the DMH Editor
software when alignment or adjustment is required. You will need an IBM or compatible
computer with a disk drive and an RS-232 serial port. You will also need the DMH Editor
software (LAA0742CD) and an RS-232 interface cable (LAA0725), available from BK Radio.
5.5.1 TEST SETUP
Mount the radio in a suitable fixture containing an adapter for supplying 13.8 VDC from a
negative ground power supply. Turn off any radio features assigned to the microphone keypad
function menu and set the manual controls as follows:
Channel Selector: Channel 1
On/Off Volume: On, volume minimum
5.5.2 ALIGNMENT ORDER
When more than one procedure is necessary, follow the order listed:
A. Synthesizer Calibration
B. Reference Oscillator Frequency
C. Transmit Power Curve
D. Transmit Power Adjustment
E. VCO Modulation Sensitivity
F. Receiver Tuning
G. Squelch Adjust