Panel Section; Rx Bpf Switching Frequency; Vhf Bpf Shift Frequency; Power Supply Circuit - Kenwood TM-D710A Service Manual

TM-D710A/D710E
Band B 1st IF: 49.95MHz, 2nd IF: 450kHz (Upper)
RX frequency range [MHz]
136.000 185.995
186.000 224.995
225.000 279.995
280.000 359.995
360.000 399.995
400.000 429.995
430.000 523.995
800.000 823.990
824.000 909.990
910.000 1109.990
1100.000 1209.990
1210.000 1299.990

RX BPF switching frequency

Band A
Band B

VHF BPF shift frequency

BPF shift switch
IC576 pin 16
IC577 pin 17

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
4
CIRCUIT DESCRIPTION
VCO oscillation frequency
Multiply
range [MHz]
185.950 235.945
136.050 175.045
175.050 230.045
329.950 409.945
409.950 449.945
350.050 380.045
380.050 474.045
375.0250 387.0200
436.9750 479.9700
319.9833 386.6467
350.0167 386.6800
314.9875 337.4850
118~279.995MHz (5RVA : ON)
136~279.995MHz (5RVB : ON)
VCO V/U VCO shift
IC577 pin 7 IC577 pin 12
1 H H
1 H L
1 H H
1 L L
1 L H
1 L L
1 L H
2 L L
2 L H
3 L L
3 L L
4 L L
VHF BPF
RX frequency
~199.995MHz
L
L
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.
Local frequency
1st Mix.
range [MHz]
Upper 185.950 235.945
Lower 136.050 175.045
Lower 175.050 230.045
Upper 329.950 409.945
Upper 409.950 449.945
Lower 350.050 380.045
Lower 380.050 474.045
Lower 750.050 774.040
Upper 873.950 959.940
Upper 959.950 1159.940
Lower 1050.050 1160.040
Upper 1259.950 1349.940
UHF BPF
280~523.995MHz (5RUA : ON)
280~523.995MHz (5RUB : ON)
200MHz~
H
H