UHF/VHF FM TRANSCEIVER PX-777/328/338

SERVICE MANUAL

------------------CONTENTS-------------------------INTRODUCTION2 GENERAL... 2 REALIGNMENT.3 TROUBLE SHOOTING GUIDE6 TECHNICAL SPECIFICATION.. 7 FUNCTION SPECIFICATION.8 CIRCUIT DESCRIPTION.. 9 SEMICONDUCTOR DATA... 16 PARTS LIST... 17 BLOCK DIAGRAM.. 22 PCB BOARD23 SCHEMATIC DIAGRAM.. 25

INTRODUCTION

SCOPE OF THIS MANUAL This manual is intended for use by experienced technicians familiar with similar types of commercial grade communications equipment. It contains all required service information for the equipment and is current as of the publication data. Changes which may occur after publication are covered by either Service Bulletins or Manual Revisions. These are issued as required.
ORDERING REPLACEMENT PARTS
When ordering replacement parts or equipment information, the full part identification number should be included. This applies to all parts : components, kits, or chassis. If the part number is not known, include the chassis or kit number of which it is a part, and a sufficient description of the required component for proper identification.

PERSONNEL SAFETY

The following precautions are recommended for personnel safety: DO NOT transmit until all RF connectors are verified secure and any open connectors are properly terminated. SHUT OFF and DO NOT operate this equipment near electrical blasting caps or in an explosive atmosphere. This equipment should be serviced by a qualified technician only.

SERVICE

This radio is designed for easy servicing. Refer to the schematic diagrams, printed circuit board views, and alignment procedures contained within.

GENERAL

Your Transceiver is an electronic product of exact design and should be treated with care.The suggestions below will help you to fulfill any warranty obligations and to enjoy this product for many years. Do not attempt to open the unit. Non-expert handling of the unit may damage it. When using regulated power supply, take notice of power voltage must be between 6V and 8V to avoid damaging the unit. Do not store the Radio under the sunshine or in hot areas. High temperatures can shorten the life of electronic devices, and warp or melt certain plastics. Do not store the Radio in dusty, dirty areas Keep the Radio dry. Rainwater or damp will corrode electronic circuits. If it appears that the Radio diffuses peculiar smell or smoke, please shut off its power immediately and take off charger or battery in the Radio, then contact with PUXING agency. Do not transmit without antenna.

REALIGNMENT

1. MODE:
USER MODE: For normal use, when turn on enter this mode. PC MODE: used to read and program radio. SELF-PROGRAMMING MODE: Hold down [MONI] and [menu] key accomplished by turning on the VOL/POWER switch until SELF displays.

2. LCD DISPLAY

3. SELF-PROGRAMMING MODE
For frequency,signal,feature write to the radio

TECHNICAL SPECIFICATION

General Frequency Range Working Temperate Operating Voltage Operate Mode Channel spacing Dimension Weight Antenna impedance Transmitter Frequency Stability Output Power Max Frequency Deviation Audio Distortion Modulation Character Adjacent Channel Power Spurious Radiation Occupied Bandwidth Receiver RF Sensitivity Audio Distortion Audio Response Adjacent Channel Selectivity Intermodulation Rejection Spurious Response Blocking 136 174MHz 350 390MHz 400 470MHz,245Mhz 2050 DC 7.2V Simplex or Semi-duplex 25Khz/12.5Khz 100mm55mm32mm (Not included Antenna) 220g (Including battery) 50
2.5PPM 5W/4W 0.5W 5KHz 3% +3dB-3dB 65dB 7.5UW 16KHz
0.2UV 3% +2dB-10dB 60dB 60dB 60dB 80dB
CPU PIN FUNCTION ITEM DESCRIPTION 1 CLK ROM 2 DDDDPLL CS 7 LAMPKKKKAVDD 13 RXRXTXTXBEEP/QT 18 ACC 19 AVSS 20 APC/TUNE 21 AT X 22 AR X 23 BATT Test 24 VOX 25 AN SQL 26 OSCin 27 OSCout 28 VSS 29 ENENMONI 32 Reset 33 Vdd 34 5TC 35 LED G 36 TXD/LED R 37 AFC 38 5CC 39 P-AMP 40 N/W/LD 41 PTT/RX D 42 HT1621 CS 43 LAMPDQT

PX-777 I/O I/O O O O O O O I I I I O I I O O FUNCTION CLOCK AND EEPROM Key scan output Key scan output PLL clock port/Key scan output PLL data port/Key scan output PLL CS port Lcd/backlight control output Key scan input Key scan input Key scan input Key scan input MPU+5MV IF output control port IF input control port MIC input control port MIC output control port BEEP output /CCTCS tone signal output MPU power filter Connect to VSS Automatic power &frequency automatic gain output Transmitter data output select control Receiver data input/audio amplifier adjustment input Battery check /Reset VOX input Squelch signal input port Internal oscillator input Internal oscillator output GND Encoder data input Encoder data input Monitor key input CPU reset port +5V power supply TX power supply control output LED green RX232 output/ LED red Audio amplifier control input Power supply control output Audio amplifier power supply control output Unlock detection PTT key input/RX232 input LCD CS port Backlight control output DTC audio signal output
O O I O I I I O I I I I O O O O O O O I I O O
PX777 part list(136-174MHz)
Footprint C0402 C0402 C0402 C0402 Comment Quantity 0.5P 1P 1.5P 100P C332 C231 C346 C423 C535 C416 C387_1 C121 C156 R808 C123 C413 C623 C450 C174 C668 C514 CAP C411 C663_1 C103 C182 CAP C201 C517 C263 C348 C259 C224 C113 18NH C327 C264 C591 C272 C421 C256 C353 C414 C134 C426 C516 C349

Designators

C456 C536 C415 C318_1 C132 C223 C386_1 C455 C269 CAP C665_1 C181 C454 C392 CAP C453
C0402 C0402 C0402 C0402 C0402 C0402 C0402 C0402 C0402 C0402 C0402 C0402 C0402 C0402 C0402 C0402
105P 10P 120P 12P 15P 18P 1P 220P 222P 223P 224P 22P 273P 27P 332P 333P
C315 C317_2 C313_2 C175 C537 C538 C315_2 C314_2 CAP CAP C593 CAP C316_2 C312_2 C326_1 C227 C135 C133 C142 C144 C222 C322 C612 CAP C146 C145 C176 C122 C515 C254 C610 C451 C633 C529 C528 C613 C105 C581 C520 C701 C244 C247 C321 C351 C621 CAP C594 C301 C391 C257 C268 C266 C267 C202 C203 C561 C271 C388_1 C319_1 C250 CAP C101 C573 C571 C511 C521 C208 C316 CAP C354 C662 C302 C418 C102 C147 C661 C131 C611 C609 C664 C255 C361 C363 C362 C213 C330 C331 C241 C523 C265 C359 C246 C329 C394

C556 C432

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C0402 C0402

33P 3P
C0402 C0402 C0402 C0402 C0402 C0402 C0402 CC0603 C0603 C0603 C0603 C0603 C0603 C0603 C0603 C0805 C0805 C0805 C0805 R0402 R0402 R0402 R0402 R0402 R0402 R0402 R0402 R0402 R0402
473P 47P 5P 680P 683P 6P 82P 8P 10P 15P 20P 22P 470P 56P 6P 104P 0.1uF 1uF 2.2uF 4.7uF
C126 C226 C262 C112 C177 C356 C412 C180 C424 C393 C215 C428 C543 C352 C395 C211 C163 C153 C152 C168 C162 C155 C325 L333 E367_1 E454 E435 E412
C343 C232 C258 C111 C317 C358 C622 C260 C431 C324 C433
C546 C127 C243 C313 C632 C532 C458 C347
C666 C125 C314 C204 C531 C173
C311 C141 C355 CAP C534 C667

T131 U631 T331 T251 T361 T181 T452 T141 D411 T111 T181 T411 T313 T662 T661 T663 E457 E456 CR521 FL251 CR311_1 VR552 VR471 L151 L163 L165 L142 L211
U621 T341 T393 T352 T171 T544 T521 T171

T351 T101 T301 T521 T301

2SC4226 2SC4226

L167 L212

0.4*1.5*3 0.4*1.5*4 0.4*1.5*5 0.31*1.5*8 0.31*1.5*6
FL261 U511 ANT111 CR261 JK591 JK592 C681 AN593 AN591 AN592

PR311 1K

C313 101P

C314 101P

C315 101P
MOD R368 560R R367 R365 2K2 R366 6K8 E363 1uF R363 0R R364 4K7 E364 0.1uF R362 150R R361 0R L361 101T L351 270nH C351 100P

L329 101T D351

R333 15K C353 33P C352 2P L353 18nH C355 15P C347 102P
L347 100nH C360 7P T351 2SK508NV(K52)
C362 1P L355 3.3uH R351 180R

C906 471P U906 5A in out

560R 28.8MHZ DQTo PLL_CS PC4 PC3 N/W/LD E367 0.1uF
1SV325 L352 270nH D352 1SV325
5V E905 10uF C905 103P R816 10K 5C 5V

E907 10uF

C907 103P
C359 5P 5CC P-TX/RX 5C 5V DQTo 5M 28.8MHZ MOD

C361 10P

R813 560R D814 GREEN T813 DTC114EE
R814 560R D813 RED T814 DTC114EE
T815 DTA114EE R817 4K7 R815 4K7 C817 104P R545 10K R852 R-1 R853 58K C852 221P C853 101P PC0 PC6
R283 R374 R378 NC R379 NC RV378 100K C280 103P E283 100R 10uF C285 221P C286 221P

FL261 C281 450K 102P

C850 104P
TXD/RED GREEN N/W/LD P-TX/RX 5CC

R818 C818 104P

L851 101T R701 0R R717 10K R371 4K7 R372 4K7

R375 4K7

1K2 C372 103P
PB5 PB4 PB3 PC7 PC6 PC5 PC4 PC3 PC2 PC1 PC0

4K7 R546 330K

SDA SCL OSC RST GND GND VOUT VDD 6 5

C851 104P

R287 3K9 R286 180K
C283 104P C284 R285 104P 180K C271 20P
2 GND OSC out Dec FIL in IF in Vcc N-rec MIX out
C282 104P CR272 21.250MHz

C546 104P C547 103P

C549 104P U821 BEEP R549 4K7 R831 150K
A0 Vcc A1 WP A2 CK GND DA 6 5
0R T881 R885 15K C885 103P R884 82K
PB1 PB5 PB4 PB3 PC7 PC4 PC3 PC2 PC1

R383 RES

R389 180R

VR351 50K R388

C388 104P

C387 102P

5C VC X OUT GND 3 2
T352 UMC4 R332 100R L336 22nH T332 2SJ243 R346 1K C343 470P C345 470P R345 100K C342 1P L335 3.3uH R331 150R R392 120K 5R
14.4MHz R387 39K C386 102P D312 PMSD4148 R312 1K
100nH R381 10K C381 47P T362 2SC4215 R382 220K L382 100nH

C385 82P

C317 101P
C383 560P R376 22K R377 22K

E377 4.7uF

C344 104P
R347 22R C340 5P C338 1P T331 2SK508NV(K52) 2SC3356

C382 390P

C384 CAP

R313 NC

R311 150K U311 C312 LMX2332 NC

GND_AGND_A

OSC in

GND_D GND_D

C326 102P

E326 4.7uF

f in RF
D331 1SV325 D332 1SV325 L332 180nH

C333 27P C332 2P

f in IF
R326 0R PR311 1K C313 101P C314 101P C315 101P C316 102P
C339 4P L347 100nH C360 7P

C341 5P

T351 2SK508NV(K52)
C539 R872 R871 E871 4K7 C871 R873 4K7 C872 C540 104P R540 100K 120P R539 100K

R713 100R

R714 100R
P_TX 5C C394 471P R393 100R C395 103P 5T R138 47K
P_TX 5T L142 101T C144 470P

C113 103P R111 15K

C114 470P
R114 22R C122 470P L122 15nH R123 C115 7P 150K

L123 101T

C128 102P

R128 120K C132 N.U.

L132 101T L131 15nH L133 22nH T131 2SK3078 C131 33P
C138 470P C137 470P C134 102P C133 27P R135 0R R137 47K

C142 1uF C143 103P

R391 680R L391 100nH C392 T391 2SC3356 33P C393 15P L393 47nH R396 3K3 R397 220R R395 5K6 R394 3K3

C112 470P R113 33K

L112 18nH

R122 330R

R392 120K

C391 102P

L392 22nH

C127 470P R124

R127 47K

R126 22R

R136 47R T141 2SK3476 C141 NC

L143 8T

C145 104P

C146 103P

C396 102P R398 0R R399 3K3 C390 NC D111 HSC277 C111 470P
R153 0R C151 1P C152 22P C153 NC

T392 2SC3356

C397 P C398 102P

T111 2SC3356

T121 2SC4988 R115 680R R121 22R

C123 6P

10R C124 104P

C125 470P C129 N.U.

R125 0R C126 N.U.

C135 N.U.

C136 NC

C121 470P

D213 HSC277 5C 5T 5V R256 18K C256 103P C201 103P T201 DTA114EE
T301 DTA114EE C302 103P R301 1K C303 470P
BATT 5V C181 102P E181 4.7uF (T.Y.) C173 103P R195 150K

5V C301 103P

5VOX C412 103P C416 R413 5K6 R414
3.58MHz R537 1M C537 5CC R408 C410 103P R409
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P_TX 5T R138 47K L142 101T C144 470P R158 270R C143 103P L143 8T C145 104P C146 103P C158 NC R153 C141 NC 0R C151 1P C152 22P C153 NC C154 15P C157 470P C156 C155 27P 7P R157 270R L157 220nH D156 HVU131 C162 470P C161 3P L211 4T R211 0R D212 HSC277 BATT D211 HSC277 C211 2P L161 4T C163 10P C166 2P L162 4T C164 9P C167 5P L163 3T C165 10P C168 3P C169 1.5P L164 1uH ANT111 ANT

File No.: PUXING-UPCG-001 Date of Issue: 2008-2-15
Guide to USB Programming Cable Usage
Compatible Radios This Guide is intended for programming of HYT radio models specified in the table below.
Radio Model PX-333, PX-888, PX-777(PLUS), PX-328 PX-628, PX-555, PX-666, PX-728, PX-58/28, PX-398S PX-PCU7 USB Programming Cable
Procedures 1. Install the USB driver SETUP.exe 2. Install the programming software of PUXING radio. 3. Startup the programming software. 4. Connect the USB programming cable. 5. Select a communication port.
The communication port varies according to the USB port. To make sure and correctly select the communication port for USB programming cable, view the detailed information of port from the computer hardware Device Manger after connecting a USB device to a computer. Take WINDOWS 2000 for example, right-click My Computer -> Properties -> Hardware -> Device Manager, to view the detailed information. As shown in the above figure, COM7 is the communication port for USB programming cable. Then select a communication port from the programming software. Operation for PX-888 radio is illustrated in the following figure:
To select a communication port
6. Begin writing and reading operations. Precautions Always obey the following guidelines when using a USB programming cable: 1. The USB driver must be installed. 2. After connecting USB programming cable to a computer, a communication port must be selected correctly.