QUANTUN QP650U Plus User manual

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QP-650U Plus Service Manual
Quantun Electronics，LLC

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Revised History
No: Date Decription Version Note
1 2010-3-9 Issue V0.1A

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Content
General……………………………………………………………………………3
Brief Introduction………………………………………………………………..4
Software Description…………………………………………………………..6
Circuit Description……………………………………………………………..10
CPU Pins…………………………………………………………………………15
Part List 1………………………………………………………………………..17
Adjustment Description……………………………………………………….49
Disassembly and Assembly………………………………………………..52
Exploded View………………………………………………………………..56
Part List 2……………………………………………………………………….57
PC Board View………………………………………………………………….58
Block Diagram…………………………………………………………………..62
Schematic Diagram…………………………………………………………..63
Specifications…………………………………………………………………66

QP-650U Plus General
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General
Manual Scope
This manual is intended for use by experienced technicians familiar with similar types of
communication equipment. It contains all service information required for the equipment and is
current as of the publication date.
User Safety Information
The following precautions are recommended for personnel safety:
zDO NOT transmit until all RF connectors are verified secure and any open connectors are
properly terminated.
zSHUT OFF and do not operate this equipment near electrical blasting caps or in an explosive
atmosphere.
zWhen in vehicles with an airbag, do not place a portable radio in the area over an airbag or in the
airbag deployment area.
zDo not expose the radio to direct sunlight for a long time nor place it close to a heating source.
zDo not use any portable radio with a damaged antenna. If a damaged antenna comes into contact
with your skin, a minor burn may result.
zWhen transmitting with a portable radio, hold the radio in a vertical position with its microphone
about 5 centimeters away from your mouth.
zIf you wear a portable radio on your body, be sure to keep the antenna at least 2.5 centimeters
away from your head or body when transmitting.
zThis equipment should be serviced by qualified technicians only.

QP-650U Plus Brief Introduction
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Brief Introduction
1. Antenna
2. LED indicator
The light will glow red during transmission. The light will glow green during receiving. During
transmission, the light flashes red when the battery voltage is low.
3. Channel selector knob
Turn the channel selector knob to select from channels 1-16 (Channel 16 can be programmed by
your dealer as scan function).
4. Power/Volume control knob
Rotate the Power/Volume Knob clockwise until a “click” is heard to turn the radio on, fully counter
clockwise until a “click” is heard to turn the radio off. When the radio is on, turn the knob to adjust
volume.
5. PTT key
Press and hold PTT key to talk, release to receive.
6. SK1 (Side Key) (programmable)
Your dealer may program the SK1 (long or short press) keys with one of the following auxiliary
functions respectively.

QP-650U Plus Brief Introduction
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1)VOX
2)Power Level
3)monitor
4)monitor momentary
5)scan
6)squelch off
7)squelch off momentary
8)channel lock
9) battery indicator
7. Microphone
8. Speaker
9. External jack
Remove the jack cover and insert an earphone; or insert programming cable into the jack to
program the radio via programming software.
10. Battery
11. Belt clip
Used to clip radio on your belt.
12. Battery latch
Used to fasten and remove the battery.
13. Charging connectors
Connect the charging connectors with that on the charger to begin charging.

QP-650U Plus Software Specification
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Software Specification
Radio Feature Description
1. Use channel selector knob to choose from 16 channels
2. Channel Annunciation, The feature enables radio to report the current channel number when power on or switching
channel,.
3. Channel Spacing
12.5KHz/20KHz/25KHz Narrow/Middle/wide Optional
4. High/low Power (Dealer programmable)
5. CTCSS/CDCSS
51+104 groups, user definable
6. DTMF PTT ID
7. Side key function programmable
8. Monitor
9. channel lock
10. Channel Scan (Priority channel and scan revert channel available)
11. VOX (9 levels)
12. Battery Save feature (Dealer programmable)
13. Time-out Timer (TOT)
14. Squelch Level Control (9 levels)
15. Low Battery Alert
16. Reset Mode
17. PC Programming
18. User Wired Clone Mode
19. Manual Adjust Mode
Radio Modes
1. User Mode:
User mode is conventional communication mode. Turn the power on, the radio enters user mode.
2. Reset Mode
(1) Turn channel selector knob to the corresponding position 16.
(2) Holding down PTT and Side key , and then turn the power on. After 2 seconds release PTT and Side key with
orange LED flashing.
(3) Press Side key for 3 seconds and meanwhile turn channel selector to CH13, the Red LED lights. Channel
data and settings begin to be initialized (Refer to the initial data table).when finished the red LED turn off.
Remarks: The data (frequency, CTCSS/CDCSS, channel function settings) will be changed once the radio is reset, and
part of functions will also be changed. Therefore, do not make this operation unless it’s very necessary, such as
changing the EEPROM, etc.
3. PC Programming Mode
The following parameters can be set through programming software (Refer to the figure2):
（1） Receive frequency and transmit frequency
（2） Receive signaling and transmit signaling
（3） N/M/W setting

QP-650U Plus Software Specification
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（4） High/low power
（5） Busy channel lockout
（6） Tail Elimination
（7） VOX level
（8） Squelch level
（9） Time-out timer
（10） DTMF PTT ID
（11） VOX level
（12） Scan mode
（13） Scan revert channel
（14） Priority scan channel
（15） Channel Annunciation
（16） Annunciation voice level
（17） Battery save
（18） Key assignment
Power level
Monitor mode
Squelch off mode
VOX toggle
Channel lock
Battery indicator

QP-650U Plus Software Specification
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4. Manual Adjust Mode
(1) Enter the manual adjust mode
Turn channel knob to Channel1, Turn on the power while holding down PTT and Side key simultaneously for 2
seconds, orange LED will flashing two times., release the PTT and SK1 key , then press PTT button for 2 seconds,
the red led flashes and release the two keys again, the radio enters manual adjust mode.
(2) Select adjusting item
In manual adjust mode, select the adjusting item by turning the channel selector knob to CH2-CH16 while holding
down PTT and side key, the item are defined as follows:
Channel NO. Adjust item
2 TX Low Power
3 TX High Power
4 TX CDC Deviation
5 TX CTC(67Hz) Deviation
6 TX CTC(151.8Hz) Deviation
7 TX CTC(254.1Hz) Deviation
8 TX DTMF Deviation
9 VOX Level 1
10 VOX Level 5
11 TX Low battery threshold
12 RX sensitivity
13 Squelch open level 1
14 Squelch open level 9
15 Squelch shut level 1
16 Squelch shut level 9
(3) Adjusting Operation
When the radio enter a adjusting item, the channel selector is used to choose the frequency point and bandwidth,
the PTT and SK1 is pressed to upward/downward the adjusting value. The details is as following:
PTT/SK1
PTT→Increase
SK1→Decrease

QP-650U Plus Software Specification
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Defination
CH. NO. Frequency Bandwidth
1 F1 W
2 F2 W
3 F3 W
4 F4 W
5 F5 W
6 F3 M
7 F1 N
8 F3 N
9 F5 N
5. User Wired Clone Mode
(1). Turn on the power while holding down Side key for 2 seconds, green LED flash two times, the radio enters
wired clone mode.
(2). Press the PTT key to begin wired clone and slave radio red LED lights, when clone is completed, master radio
orange led lights, and slave radio red Led goes out.
6. Aging Test Mode
Aging Test Mode is used for quality control in factory.

QP-650U Plus Circuit Description
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Circuit Description
1. Power Supply
Power supply of the radio is derived from the battery, which supplies battery B+ through power
switch. U608 supplies 5V (5M) voltage for the control circuit. U607 supplies 3V voltage for the PLL circuit.
And U200 supplies voltage for the transmit(V_TX), receive(V_RX) and vco(V_SAVE) circuit.
Fig. 1 Power Supply Block Diagram
2．PLL frequency synthesizer
PLL circuit generates the first local oscillator signal for reception and RF signal for transmission.
Fig.2 PLL Block Diagram
PLL circuit
Step frequency of PLL can be 2.5 KHz, 5.0 KHz or 6.25 KHz. A 12.8MHz reference oscillator signal
is divided at U610 by a counter to generate a 2.5 KHz, 5.0 KHz or 6.25 KHz reference frequency. Output
signal from VCO is buffer amplified by Q103 and divided at U610 by a frequency divider. The divided
signal is compared with 2.5 KHz, 5.0 KHz or 6.25 KHz reference signal in the phase comparator of U610.

QP-650U Plus Circuit Description
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The output signal from phase comparator is filtered through a low pass filter to generate a level D.C., and
the level D.C. controls oscillator frequency by controlling VCO.
VCO
The operating frequency is generated by Q100 in transmit mode and by Q101 in receive mode.
Operating frequency generate a control voltage by phase comparator to control varactor diodes so that
the oscillator frequency is consistent with the MCU preset frequency(D100、D101、D104 and D105 in
transmit mode, and D102、D103、D106 and D107 in receive mode). T/R pin is set high level in receive
mode, and low level in transmit mode. The output from Q100 and Q101 is amplified by Q103 and sent to
buffer amplifier.
Unlock detector
An unlock condition appears if low level appears at MUXOUT pin of U610. Transmission is
forbidden if this condition is detected by microprocessor.
3．Receiver
The receiver utilizes double conversion superheterodyne
Fig. 3 Receiver Section Configuration
Front-end RF Amplifier
The signal from antenna is amplified at RF amplifier (Q500) after passing through a transmit/receive
circuit and a band pass filter. Before passing the first mixer, the amplified signal is filtered through
another band pass filter to remove unwanted signals.
First Mixer
The signal from RF amplifier is mixed with the first local from PLL frequency synthesizer circuit at
the fix mixer (Q501) to create a 38.85MHz first IF signal. The first IF signal is then fed through a crystal
filter (XF1) to further remove unwanted signals.
IF Amplifier
The first IF signal is amplified by Q502 before passing through crystal filter after crystal filter and
then enters IF processing chip U200. The signal from U200 is mixed with the second oscillator signal

QP-650U Plus Circuit Description
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again in U200 to create a 450 KHz second IF signal. The second IF signal then passes through a
450KHz ceramic filter to eliminate unwanted signals before it is amplified and detected in U200.
4. Transmitter
AF and signaling
AF signal from the microphone is amplified and low-pass-filtered in U200, which also enters
CYC/CDC/DTMF etc signaling generated by CPU. The U200 processed mixing signal enters VCO for
direct FM modulation (see fig.5).
RF Power Amplifier
The transmit signal from VCO buffer amplifier （Q102）is amplified by Q104 and Q400. The
amplified signal is then amplified by the power amplifier Q402 and Q403 (including a two-stage FET
amplifier) to create 5.0W RF power (see Fig. 4).
Fig. 4 APC System
Antenna switch and LPF
Output signal from RF amplifier passes through a low-pass filter network and a transmit/receive
switch circuit comprised of D401，D501 and D502 before it reaches the antenna terminal. D501 and
D502 is turned on (conductive) in transmit mode and off (isolated) in receive mode.
APC
The automatic power control (APC) circuit stabilizes the transmit output power by detecting the
drain current of final stage amplifier FET. U430 (2/2) compares the preset reference voltage with the
voltage obtained from final current. APC voltage is proportional to the difference between auto detect
voltage and reference voltage output from U430（1/2）. The output voltage controls FET power.

QP-650U Plus Circuit Description
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5. Base band and signaling system
The block diagram of signaling section is shown as figure 5.
Fig. 5 AF and Signaling Circuit
CTC/CDC
Transmit: CTC/CDC signaling produced by CTC_PLL pass a low pass filter and then enters
VCXO. CTC/CDC signaling produced by CTC_OUT pass a low pass filter and then mixed with AF
before enters VCO.
Receive: Demodulated signal enters MCU after pass U200. MCU then judges whether CTC/CDC
matches the preset values or not. According the result, the out tone will be controlled by AFMUTE.
DTMF
Transmit: The signal produced by MCU provides a TX and SP out tone, and is then applied to the
base band processing IC. The signal in mixed with the audio signal and goes to the VCO。
AF
Transmit: AF signal from MIC enters base band processed IC for amplification, pre-emphasis etc.
after being amplified. And then it enters VCO for modulation.
Receive: Demodulated AF signal enters the base band processing IC for amplification,
de-emphasis etc. after being amplified. And then it enters AF power amplifier drived speaker.
Base band processed chip provides functions for processing signal as amplifying, filtering,
amplitude limiting.
6. Control system
The U611 CPU operates at 19.6608 MHz.
The block diagram of MCU control system is shown as following：

QP-650U Plus Circuit Description
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PTT/RXD RSSI
MONI BUSY
QT_IN VOXDET
BATT LD
BEEP APC_SW
DTMFO QT_OUT
APC/TV SAVE
W/N M_Band
SPV_C MIC_EN
CTC/CDC Code
PLL IC
Audio Processor
TXD/RXD
Fig.6 MCU Block Diagram
Circuit in this section is mainly comprised of MCU, EEPROM etc.
MCU control circuit accomplishes the following functions: accomplish the reset initialization
according to the programmed feature of the radio when power on; detect keying signal and monitor
battery voltage; send necessary frequency data to PLL according to encode of the channel; switch and
control transmit/receive according to the signal input from PTT; turn on/off the mute circuit according to
the input signaling decode signal and squelch level signal; output control signal to control the light/off of
LED; control signaling process IC to perform tasks.
.

QP-650U Plus MCU PINS
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CPU Pins
PIN No. PIN Name I/O Description
1 NC
2 SDL I/O EEPROM DATA
3 MODE
4 NC
5 NC
6 RESET I Reset input
7 XOUT Crystal oscillator output pin
8 GND GND
9 XIN Crystal oscillator input pin
10 VCC I VCC
11 NC
12 DTMF O DTMF output
13 APC/TV O Power control/ receiver tuning out
14 PLLCLK O PLL clock output
15 NC
16 PLLEN O PLL strobe output
17 W/N O 0: Wideband control 1: Narrowband control
18 PLLDATA O PLL data output
19 NC
20 NC
21 M_band O Medium band control
22 SAVE O Power save control
23 NC
24 T/R O Receive/transmit VCO control
25 NC
26 RXD I/O Serial date input.
27 TXD I/O Serial date output.
28 SPV_C O SPV_C
29 LD I PLLunlockdetect
30 EN3 I Channel coded in
31 NC
32 EN2 I Channel coded in
33 EN1 I Channel coded in
34 EN0 I Channel coded in
35 NC
36 MIC_EN O MIC_EN
37 NC

QP-650U Plus MCU PINS
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PIN No. PIN Name I/O Description
38 NC
39 NC
40 LEDR O Red light control：H，lit；L，out
41 LEDG O Green light control：H，lit；L，out
42 PTT I PTT key IN
43 SK1 I Side Key1
44 EXT_DEV I EXT_DEV detect
45 APCSW O APC SW
46 NC
47 NC
48 NC
49 NC
50 BUSY I Squelch level input
51 BATT I Battery voltage detect
52 VOXDET I VOX level input
53 RSSI I RSSI level input
54 QT_IN I CTC/DCS in
55 CLK O AN29160 CLK
56 DATA I/O AN29160 DATA
57 EN O AN29160 EN
58 QT_OUT O QT_OUT
59 GND GND
60 BEEP O BEEP tone output
61 VCC I
62 VCC I
63 NC
64 SCL O EEPROM CLK

QP-650U Plus Part list1
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Part list 1
NO. P/N Description Refer. NO. Qty. Note
1 1501061040 Capacitor 0603 0.1UF K 50V C100 1
2 1701084750 TAN-Capacitor 0805 4.7UF M 10V C101 1
3 1701121060 TAN-Capacitor 1206 0.1UF M 16V C102 1
4 1501041030 Capacitor 0402 0.01UF K 25V C105 1
5 1501041020 Capacitor 0402 1000PF K 50V C106 1
6 1501041010 Capacitor 0402 100PF J 50V C107 1
7 1501044700 Capacitor 0402 47PF J 50V C110 1
8 1501040300 Capacitor 0402 3PF B 50V C111 1
9 1501040590 Capacitor 0402 0.5PF B 50V C112 1
10 1501040400 Capacitor 0402 4PF B 50V C113 1
11 1501040300 Capacitor 0402 3PF B 50V C114 1
12 1501040500 Capacitor 0402 5PF B 50V C115 1
13 1501060590 Capacitor 0603 0.5PF B 50V C116 1
14 1501041040 Capacitor 0402 0.1UF K 16V C118 1
15 1501043900 Capacitor 0402 39PF J 50V C120 1
16 1501040300 Capacitor 0402 3PF B 50V C121 1
17 1501040400 Capacitor 0402 4PF B 50V C122 1
18 1501040300 Capacitor 0402 3PF B 50V C123 1

QP-650U Plus Part list1
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NO. P/N Description Refer. NO. Qty. Note
19 1501040600 Capacitor 0402 6PF B 50V C124 1
20 1501060590 Capacitor 0603 0.5PF B 50V C125 1
21 1501061040 Capacitor 0603 0.1UF K 50V C126 1
22 1501041040 Capacitor 0402 0.1UF K 16V C127 1
23 1501040600 Capacitor 0402 6PF B 50V C130 1
24 1501041020 Capacitor 0402 1000PF K 50V C131 1
25 1501040500 Capacitor 0402 5PF B 50V C132 1
26 1501042200 Capacitor 0402 22PF J 50V C133 1
27 1501044710 Capacitor 0402 470PF J 50V C134 1
28 1501041000 Capacitor 0402 10PF J 50V C135 1
29 1501040500 Capacitor 0402 5PF B 50V C136 1
30 1501040300 Capacitor 0402 3PF B 50V C137 1
31 1501040500 Capacitor 0402 5PF B 50V C138 1
32 1501041020 Capacitor 0402 1000PF K 50V C139 1
33 1501041020 Capacitor 0402 1000PF K 50V C140 1
34 1501040600 Capacitor 0402 6PF B 50V C141 1
35 1501044710 Capacitor 0402 470PF J 50V C142 1
36 1501041040 Capacitor 0402 0.1UF K 16V C143 1
37 1701084750 TAN-Capacitor 0805 4.7UF M 10V C200 1

QP-650U Plus Part list1
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NO. P/N Description Refer. NO. Qty. Note
38 1501044710 Capacitor 0402 470PF J 50V C201 1
39 1501044740 Capacitor 0402 0.47UF Z 25V C202 1
40 1501042240 Capacitor 0402 0.22UF Z 25V C203 1
41 1501041020 Capacitor 0402 1000PF K 50V C204 1
42 1501041040 Capacitor 0402 0.1UF K 16V C205 1
43 1501044710 Capacitor 0402 470PF J 50V C206 1
44 1501041830 Capacitor 0402 0.018UF K 25V C207 1
45 1501041010 Capacitor 0402 100PF J 50V C208 1
46 1501041510 Capacitor 0402 150PF J 50V C213 1
47 1501042230 Capacitor 0402 0.022UF K 25V C215 1
48 1501041050 Capacitor 0402 1UF K 6.3V C216 1
49 1501041040 Capacitor 0402 0.1UF K 16V C217 1
50 1501041050 Capacitor 0402 1UF K 6.3V C218 1
51 1501046800 Capacitor 0402 68PF J 50V C219 1
52 1501046800 Capacitor 0402 68PF J 50V C220 1
53 1501046800 Capacitor 0402 68PF J 50V C221 1
54 1101040000 Resistor 0402 0Ω J 1/16W C222 1
55 1501044730 Capacitor 0402 0.047UF K 25V C223 1
56 1501041520 Capacitor 0402 1500PF K 50V C224 1