TM-D710A/D710E
4
CIRCUIT DESCRIPTION
3. Panel Section
The panel section consists of the control section, the
TNC section and the full-dot LCD (235×65 dots) display
section.
The flash-type panel MPU (IC1) is used in the panel
section and the fi rmware can be rewritten. Also, the panel
MPU has no program for controlling frequency, so it is
common for all types.
3-1. Power Supply Circuit
10V is always supplied to the panel section even if the
power of the main unit is turned off, as long as the main
unit is connected to a power supply such as battery. Power
is applied to the panel MPU through the 5V AVR (IC6) and
the panel section is operating in standby mode.
When in standby state, the LCD power, the RS-232C
circuit power and the TNC power are turned off with
switches Q1, Q2, and Q3 respectively, in order to reduce
power consumption.
The reset signal of the panel MPU (IC1) detects the rising
edge of the voltage of the 5V line with the voltage detection
IC (IC3). The voltage detection IC (IC24) detects the reduced
voltage of the 10V power line and backs up the state
immediately before the voltage becomes approximately 8V
or less, to the EEPROM (IC2).
The voltage detection IC (IC14) monitors the TNC-5V line
and the reset signal of the TNC MPU (IC11) performs reset
operations.
The backup battery circuit divides the 5V voltage always
applied with R115 and R116 and floating-charges the
internal rechargeable lithium battery through the reverse
current prevention diode (D3). The voltage of the battery is
approximately 3.1V when fully charged.
The internal rechargeable lithium battery backs up the
data of the S-RAM (IC13), RTC (IC25) and logic IC (IC15).
The backup current of approximately 5µA is consumed. So,
the data can be saved for approximately four weeks on a full
charge.
The S-RAM is used for maintaining the status of the
packet mode.
The call sign of the APRS and reception list are stored in
the EEPROM.
Band B 1st IF: 49.95MHz, 2nd IF: 450kHz (Upper)
RX frequency range [MHz]
VCO oscillation frequency
range [MHz]
Multiply
VCO V/U
IC577 pin 7
VCO shift
IC577 pin 12
1st Mix.
Local frequency
range [MHz]
136.000
185.995
185.950
235.945
1
H
H
Upper
185.950
235.945
186.000
224.995
136.050
175.045
1
H
L
Lower
136.050
175.045
225.000
279.995
175.050
230.045
1
H
H
Lower
175.050
230.045
280.000
359.995
329.950
409.945
1
L
L
Upper
329.950
409.945
360.000
399.995
409.950
449.945
1
L
H
Upper
409.950
449.945
400.000
429.995
350.050
380.045
1
L
L
Lower
350.050
380.045
430.000
523.995
380.050
474.045
1
L
H
Lower
380.050
474.045
800.000
823.990
375.0250
387.0200
2
L
L
Lower
750.050
774.040
824.000
909.990
436.9750
479.9700
2
L
H
Upper
873.950
959.940
910.000
1109.990
319.9833
386.6467
3
L
L
Upper
959.950
1159.940
1100.000
1209.990
350.0167
386.6800
3
L
L
Lower
1050.050
1160.040
1210.000
1299.990
314.9875
337.4850
4
L
L
Upper
1259.950
1349.940
RX BPF switching frequency
VHF BPF
UHF BPF
Band A
118~279.995MHz (5RVA : ON)
280~523.995MHz (5RUA : ON)
Band B
136~279.995MHz (5RVB : ON)
280~523.995MHz (5RUB : ON)
VHF BPF shift frequency
BPF shift switch
RX frequency
~199.995MHz
200MHz~
IC576 pin 16
L
H
IC577 pin 17
L
H