Kenwood TM-V7A Service Manual

TM-V7A/E
CIRCUIT DESCRIPTION
Reset and Backup Circuits
When power is supplied to the set, the reset circuit
generates a delay in the reset IC (IC505: PST9130NR) and
the delay signal is input to the. reset terminal of the main
unit microprocessor to carry out a power ON reset. When
the power voltage drops, the voltage is detected and the
reset signal is generated.
The reset switch circuit resets the main unit microproc-
essor when the reset switch (S501) is pressed. After the
reset operations are carried out, the microprocessor goes to
look at the RSTSW port. If the switch is released within 1
second (if the RSTSW port is iow), the operations are the
same as for an ALL reset (MR + power ON). The RSTSW
port is normally low. The backup circuit detects any voltage
drop in the power supply voltage 13.8V line and sets INTO
of the microprocessor high, causing the microprocessor to
send the backup data to the EEPROM (IC512) and go into
STOP mode to reduce power consumption.
ResetSW circuit
IC501 —
D501 yy OHS Mari2 [etl 38
. I OUT 28C4738(GR
13.8V
>—4
*
—>}—+
(GR)
188355 9 tL C517
re) 2 To re) ec} tT 5
bys ols 8 xe LMACSITI O.tu. Microprocessor
SSX dss LS
a) + elt
Q501
2S8C4738(GR)
D502
R501
AAA bT47,5(B)
MWK od x
ery 10/10
i O50 RSTSW
PST9130NR_
Backup circuit 5 [4 r RESET
VDD
w Qa rT
bk Que
oy < ' OTs
1 I P INTS
Reset backup circuit
Fig.13 Reset backup circuit
15

Kenwood TM-V7A Specifications

General Specifications

VHF frequency range	144~148MHz
UHF frequency range	438~450MHz (U.S.A/Canada)
Antenna impedance	50Ω
Usable temperature range	-20°C to +60°C (-4°F to +140°F)
Power supply	13.8V DC ±15% (11.7~15.8V)
Grounding method	Negative-ground
Frequency stability	±3ppm (-10°C to +50°C)
Dimensions (W x H x D)	140 x 54.5 x 205.5 mm

Transmitter Specifications

High power output	50W (VHF) / 35W (UHF)
Mid power output	Approx. 10W
Low power output	Approx. 5W
Spurious emissions	-60dB or less
Maximum frequency deviation	±5kHz
Audio distortion	3% or less (at 60% modulation)
Microphone impedance	600Ω

Receiver Specifications

Circuitry	Double conversion
Intermediate frequency (1st / 2nd)	38.85MHz / 450kHz and 45.05MHz / 455kHz
Sensitivity (VHF or UHF band)	0.16μV or less (12dB SINAD)
Sensitivity (Sub VHF or UHF band)	0.25μV or less
Selectivity (-6dB)	12kHz or more
Selectivity (-60dB)	28kHz or less
Squelch sensitivity	0.1μV or less
Audio output	2W or higher (8 ohms, 5% distortion)
Audio output impedance	8Ω

Weight and Dimensions

Weight	1.2 kg (2.6 lb)
Dimensions (W x H x D)	5.51" x 2.15" x 8.09"