Motorola Gp328plus Gp338plus Gp338xls Detailed 6804112j28 G Manual

Troubleshooting Charts5A-35
5V
 at pin 6 of 
D3701
Is information
from µP U409
correct?
Is U3701 
Pin 18 AT 
4.54 VDC?
Is U3701 Pin 47 
AT = 13 VDC
Is U3701 Pin 19
4.3 VDC in TX?
Start
Vis u a l 
check of the 
Board OK?Correct
Problem
Check 5V 
Regulator
+5V at U3701
Pin’s
13 & 30?
Is 16.8MHz
Signal at
U3701 Pin 19?
Check Y3761, C3761, 
C3762, C3763, D3761 
& R3761
Are signals
at Pin’s 14 &
15 of U3701?
Check 
L3701, 
R3701Check Q260, 
Q261 & R260
U3701 pin 2 at 
>3V in Tx and 
-30 dBm?
Are C3721,...

5A-36Troubleshooting Charts
START
No LO?
Tx Carrier?
VCO OK
Check 
R3829
TRB = 3.2V?Pin 10 
>1V?
L3831, 
L3832, 
L3833 O/C?Change L3831, 
L3832
Change 
U3801
AUX 3 
High?
Check U3701 
Pin 2 for 3.2V
Pin 19 =0V
AUX 3 
Low?
Change 
U3801
V ctrl 0V 
or 13V?L3821, 
L3822, L3823 
Open Circuit?
Change 
U3801
Change 
L3821, 
L3822, 
L3823,L243
Change 
U3701
Check for faulty parts or dry 
joints of L3812 C3806, 
R3806, R3802 & L3801 A
A
No
No Ye s
Ye s Ye s
No
NoYe sYe s
Ye s
No
Ye sNoNoYe sYe s
No
No
Check...

5B-1
Section 5B
MODEL CHART AND TEST SPECIFICATIONS (403-470 
MHZ)
1.0 Model Chart
GP Series, UHF Band 1, 403-470 MHz
ModelDescription
AZH38RDC9AA2GP328 Plus 403-470 MHz 4W 4 CH 
AZH38RDC9AA3GP328 Plus 403-470 MHz 4W 16 CH 
AZH38RDH9AA6GP338 Plus 403-470 MHz 4W 128 CH 
AZH38RDH9DU6GP338 XLS 403-470 MHz 4W 160 CH
ItemDescription
XPMUE2048_GP328 Plus Super Tanapa 403-470 MHz 4W 4CH
XPMUE1699_GP328 Plus Super Tanapa 403-470 MHz 4W 16CH
XPMUE1700_GP338 Plus Super Tanapa 403-470 MHz 4W 128CH
XPMUE1876_GP338...

5B-2Specifications (for GP328 Plus)
2.0 Specifications (for GP328 
Plus)
General
Tr a n s m i t t e r
Receiver
All specifications are subject to change without notice.
UHF
Frequency:403-470 MHz
Channel Capacity:GP328 Plus : 4/16 Chan-
nels
Power Supply:7.5 Volts ±20%
Dimensions
   with Standard 
High  Capacity 
 
Lithium Battery:
   with Ultra High 
Capacity Lithium 
Battery:
101.5mm x 55.5mm x 
30.5mm
101mm x 55.5mm x 
35.5mm
Weight:
   with Standard 
High Capacity 
 
Lithium Battery:
   with Ultra High...

Specifications (for GP338 Plus/GP338 XLS)5B-3
3.0 Specifications (for GP338 
Plus/GP338 XLS)
General
Transmitter
Receiver
All specifications are subject to change without notice.
UHF
Frequency:403-470 MHz
Channel Capacity:GP338 Plus 128 Chan-
nels/GP338 XLS 160 
Channels
Power Supply:7.5 Volts ±20%
Dimensions
   with Standard 
High  Capacity 
 
Lithium Battery:
   with Ultra High 
Capacity Lithium 
Battery:
101.5mm x 55.5mm x 
33.0mm
101mm x 55.5mm x 
38.0mm
Weight:
   with Standard 
High Capacity...

5B-4Transmitter
4.0Transmitter
4.1 General
(Refer to Figure 5-1)
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).
4.1.1 Power Amplifier
The 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...

Transmitter5B-5
4.1.2 Antenna Switch
The 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...

5B-6Receiver
5.0 Receiver
5.1 Receiver Front-End
(Refer to UHF Receiver Front End Schematic Diagram on page 5B-21 and UHF Transmitter 
Schematic Diagram on page 5B-25)
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 to...

Receiver5B-7
The 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...

5B-8Receiver
5.3 Automatic Gain Control Circuit
(Refer to UHF Receiver Front End Schematic Diagram on page 5B-21)
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 back end 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...