Motorola Gp328 Gp338 Detailed 6804110j64 F Manual

Troubleshooting charts6B-455V
at pin 6 of
D3701Is information
frommP U409
correct?Is U3701
Pin18AT
4.54 VDC?Is U3701 Pin 47
AT = 13 VDCIs U3701 Pin 19
4.3 VDC in TX?StartVi s u a l
check of the
Board OK?Correct
ProblemCheck 5V
Regulator+5V at U3701
Pin’s
13 & 30?Is 16.8MHz
Signal at
U3701 Pin 19?Check Y3761, C3761,
C3762, C3763, D3761
& R3761Are signals
at Pin’s 14 &
15 of U3701?Check
L3701,
R3701Check Q260,
Q261 & R260U3701 pin 2 at
>3VinTxand
-30 dBm?Are C3721,
C3722,C3723,
R3721, R3722,
R3723...

6B-46Troubleshooting chartsSTARTNo LO?Tx Carrier?VCO OKCheck
R3829TRB = 3.2V?Pin 10
>1V?L3831,
L3832,
L3833 O/
C?Change
L3831, L3832Change
U3801AUX 3
High?Check U3701
Pin 2 for 3.2VPin 19
=0VAUX 3
Low?Change
U3801Vctrl0V
or 13V?L3821,
L3822,
L3823 Open
Circuit?Change
U3801Change
L3821,
L3822,
L3823,L243Change
U3701Check for faulty parts or dry
joints of L3812 C3806,
R3806, R3802 & L3801A
ANo
No Ye s
Ye s Ye s
No
NoYe sYe s
Ye s
No
Ye sNoNoYe sYe sNo
NoCheck R3811,
L3811 for dry joint
or...

6C-1Section 6C
MODEL CHART AND TEST SPECIFICATIONS (450-527
MHZ)1.0 Model ChartGP Series, UHF Band 2, 450-527 MHzModel DescriptionAZH25SDC9AA2GP328 450-527 MHz 4W 4CHAZH25SDC9AA3 GP328 450-527 MHz 4WAZH25SDH9AA6GP338 450-527 MHz 4WItem DescriptionX PMUE1564_ GP328 Super Tanapa 450-527 MHz 4W 4CHXPMUE1477_GP328 Super Tanapa 450-527 MHz 4W
X PMUE1478_ GP338 Super Tanapa 450-527 MHz 4WXPMUE1566_GP328 Tanapa 450-527 MHz 4W 4CH
X PMUE1489_ GP328 Tanapa 450-527 MHz 4WXPMUE1490_GP338 Tanapa 450-527 MHz 4W
X...

6C-2Specifications2.0 SpecificationsGeneralTransmitter
ReceiverAll specifications are subject to change without notice.UHFFrequency:450-527 MHz
Channel Capacity: GP328 : 4/16 Channels
GP338 : 128 ChannelsPower Supply:7.5 Volts±20%
Dimensions
with Standard
High Capacity
NiMH Battery:
with Ultra High
Capacity NiMH Bat-
tery:137mm x 57.5mm x
37.5mm
137mm x 57.5mm x
40mmWeight:
with Standard
High Capacity
NiMH Battery:
with Ultra High
Capacity NiMH Bat-
tery:420 g
500 g
Average Battery
Life @ (5-5-90 Duty...

Transmitter6C-33.0 Transmitter3.1 General(Refer to Figure 6-1)
The UHF transmitter contains five basic circuits:
1.power amplifier
2.antenna switch
3.harmonic filter
4.antenna matching network
5.power control integrated circuit (PCIC).3.1.1 Power AmplifierThe power amplifier consists of two devices:
1.9Z67 LDMOS driver IC (U101) and
2.PRF1507 LDMOS PA (Q110).
The 9Z67 LDMOS driver IC contains a 2 stage amplification with a supply voltage of 7.3V.
This RF power amplifier is capable of supplying an output...

6C-4Transmitter3.1.2 Antenna SwitchThe antenna switch circuit consists of two PIN diodes (CR101 and CR102), a pi network (C107, L104
and C106), and two current limiting resistors (R101, R170). In the transmit mode, B+ at PCIC (U102)
pin 23 will go low and turn on Q111 where a B+ bias is applied to the antenna switch circuit to bias the
diodes on. The shunt diode (CR102) shorts out the receiver port, and the pi network, which
operates as a quarter wave transmission line, transforms the low impedance of...

Receiver6C-54.0 Receiver4.1 Receiver Front-End(Refer toUHF Band 2 Receiver Front End Schematic Diagramon page 6C-16 andUHF Band 2
Transmitter Schematic Diagramon page 6C-20)
The RF signal is received by the antenna and applied to a low-pass filter. For UHF, the filter consists
of L101, L102, C102, C103, C104. The filtered RF signal is passed through the antenna switch. The
antenna switch circuit consists of two PIN diodes(CR101 and CR102) and a pi network (C106, L104
and C107).The signal is then applied...

6C-6ReceiverThe output of the post-RF amplifier filter which is connected to the passive double balanced mixer
consists of T301, T302 and CR306. Matching of the filter to the mixer is provided by C381. After
mixing with the first LO signal from the voltage controlled oscillator (VCO) using low side injection, the
RF signal is down-converted to the 45.1 MHz IF signal.
The IF signal coming out of the mixer is transfered to the crystal filter (FL301) through a resistor pad
and a diplexer (C322 and L310)....

Receiver6C-74.3 Automatic Gain Control Circuit(Refer toUHF Band 2 Receiver Front End Schematic Diagramon page 6C-16)
The front end automatic gain control circuit is to provide automatic gain reduction of the front end RF
amplifier via feedback. This action is necessary to prevent overloading of backend circuits. This is
achieved by drawing some of the output power from the RF amplifier’s output. At high radio
frequencies, capacitor C331 provides the low impedance path to ground for this purpose. CR308 is...

6C-8Frequency Generation Circuitry5.0 Frequency Generation CircuitryThe Frequency Generation Circuitry is composed of two main ICs, the Fractional-N synthesizer
(U201), and the VCO/Buffer IC (U241). Designed in conjunction to maximize compatibility, the two
ICs provide many of the functions that normally would require additional circuitry. The synthesizer
block diagram illustrates the interconnect and support circuitry used in the region. Refer to the
relevant schematics for the reference designators....