Motorola Gp328plus Gp338plus Gp338xls Detailed 6804112j28 G Manual

Troubleshooting charts5C-35
5V
 at pin 6 of 
CR201
Is information
from µP U409
correct?
Is U201 Pin 18 
AT 4.54 VDC?
Is U201 Pin 47 
AT = 13 VDC
Is U241 Pin 19
4.3 VDC in TX?
Start
Vis u a l 
check of the 
Board OK?Correct
Problem
Check 5V 
Regulator
+5V at U201
Pin’s
13 & 30?
Is 16.8MHz
Signal at
U201 Pin 19?
Check FL201, C206, 
C207, C208, CR203 & 
R204
Are signals
at Pin’s 14 &
15 of U201?
Check 
L202Check Q260, 
Q261 & R260
U201 pin 2 at 
>3V in Tx and 
-30 dBm?
Are R231,R232,
R233,C231,C232,
& C233...

5C-36Troubleshooting charts
START
No LO?
Tx Carrier?
VCO OK
Check 
R260
TRB = 5V?Pin 10 
>1V?
L253 O/C?Change 
L253
Change 
U241
AUX 3 
High?
Check U201 
Pin 2 for 3.2V
Pin 19 =0V
AUX 4 
High?
Change 
Q261
V ctrl 0V 
or 13V?
L243 Open 
Circuit?
Change 
U241
Change 
L243
Change 
U201
Check for faulty parts or dry 
joints of L271, L273, C370, 
C386, R339 & L320 A
A
No
No Ye s
Ye s Ye s
No
NoYe sYe s
Ye s
No
Ye sNoNoYe sYe s
No
No
Check R245 for dry 
joint or faulty
No
Troubleshooting Flow Chart for VCO 

5D-1
Section 5D
MODEL CHART AND TEST SPECIFICATIONS (330-400 
MHZ)
1.0 Model Chart
GP Series, 330-400 MHz
ModelDescription
AZH38PDC9AA3GP328 Plus 330-400 MHz 4W 16 CH 
AZH38PDH9AA6GP338 Plus 330-400 MHz 4W 128 CH 
ItemDescription
XPMUD1675GP328 Plus Super Tanapa 330-400 MHz 4W
XPMUD1676GP338 Plus Super Tanapa 330-400 MHz 4W 128CH
XPMUD1679GP328 Plus Tanapa 330-400 MHz 4W
XPMUD1680GP338 Plus Tanapa 330-400 MHz 4W 128CH
XJMHD4007GP328 Plus B/C Kit 330-400 MHz 4W
XPMHD4007GP338 Plus B/C Kit 330-400 MHz 4W...

5D-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.
330-400MHz
Frequency:330-400 MHz
Channel Capacity:GP328 Plus : 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
101.5mm x 55.5mm x 
35.5mm
Weight:
   with Standard 
High Capacity 
 
Lithium Battery:
   with...

Specifications (for GP338 Plus)5D-3
3.0 Specifications (for GP338 
Plus)
General
Transmitter
Receiver
All specifications are subject to change without notice.
330-400MHz
Frequency:330-400 MHz
Channel Capacity:GP338 Plus : 128 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 
33.0mm
101.5mm x 55.5mm x 
38.0mm
Weight:
   with Standard 
High Capacity 
 
Lithium Battery:
   with Ultra High...

5D-4Transmitter
4.0Transmitter
4.1 General
(Refer to Figure 5-1)
The  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 supplying...

Transmitter5D-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...

5D-6Receiver
5.0 Receiver
5.1 Receiver Front-End
(Refer to 330-400MHz Receiver Front End Schematic Diagram on page 5D-22 and 330-400MHz 
Transmitter Schematic Diagram on page 5D-26)
The RF signal is received by the antenna and applied to a low-pass filter. For VHF, 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...

Receiver5D-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...

5D-8Receiver
5.3 Automatic Gain Control Circuit
(Refer to 330-400MHz Receiver Front End Schematic Diagram on page 5D-22)
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....