VXR-9000 UHF Service Manual
CNTL
(
CONTROL
)
U
NIT
The CNTL Unit consists of 8-bit CPU Q3014 (HD64F2238),
EEPROM Q3006 (BR24L32F), RX and TX speech audio
circuits, and various analog switches for the CPU and re-
peater interconnections.
Microprocessor operational code is stored in Q3006
(BR24L32F), while channel data and repeater configura-
tion information is programmed from an external PC con-
nected to the front panel’s MIC jack via a VPL-1 program-
ming cable.
The output from the Main CPU Q3014 (HD64F2238) con-
tains serial control data used for REPEATER/BASE mode
control, as well as TX and RX PLL data. Crystal X3002
oscillates at 12.288 MHz, and provides stable clock tim-
ing for the Main CPU. When the repeater is powered on,
the voltage at pin 62 of Q3014 (HD64F2238) becomes sta-
ble, and the output of voltage detector IC Q3012
(BD4845FVE), which is tied to pin 59 (RST) of Q3014
(HD64F2238) becomes high, resetting the Main CPU.
BASE OPERATION (TX, MIC-INPUT AUDIO)
Microphone input is delivered past the MIC MUTE switch
Q4002 (DTC323TK), then passes through the audio am-
plifier and active high pass filter at Q4001 (NJM2902V)
when the signal is processed in the same manner as pre-
viously described.
Circuit Description
F-3
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