Alinco dj175SM Service Manual

Service Manual

DJ-175

Specifications

Circuit Description

Parts List

Exploded View

PC Board View

Adjustment

Schematic Diagram

Block Diagram

ALINCO, INC.

SPECIFICATIONS DJ-175

Frequency range:

TFH:

Modulation:

Channel steps:

Memory channels:

Antenna impedance:

Frequency stability:

Microphone impedance:

Power supply:

Current drain (Approx.):

Temperature range:

Ground:

Dimension:

Weight:

DTMF:

Subaudible Tone (CTCSS):

Digital Code SQ. (DCS):

* Guaranteed range per specifications

F3E (FM), F2D* *T/E models only

5, 10, 12.5, 20, 25 & 30KHz

200 channels + 1 CALL channel + 1 Repeater-Access function memory 50Ω unbalanced

+/- 2.5ppm

2k ohm nominal

7.2V/ 7.4V (Battery only)

1.5A Transmit high at 5W

250mA Receive at 500mW

70mA Stand-by

30mA Battery save on

-10 ~ +45

Negative ground

58(W) x 107.5(H) x 36.3(D) mm

2.28(W) x 4.23(H) x 1.43(D) inches

Approx. 245g/ 8.7oz with EBP-72 & antenna

16 Buttons Keypad

encode/ decode 39 tones

encode/ decode 104 codes

Output power (Approx.):

Modulation

Max. deviation

Spurious emission

5W (High)/ 2W (Middle)/ 0.5W (Low)

Variable reactance frequency modulation ±5KHz (±2.5KHz)**

–60dB or less

Receive system

Intermediate frequencies

Sensitivity (12dB SINAD)

Selectivity

Double conversion superheterodyne

1st: 21.7MHz / 2nd:

-14dBµ (0.2µV)

-6dB: 12KHz or more/ -60dB: 26KHz or less

(-6dB: 6KHz or more/ -60dB: 14KHz or less)**

Audio output power

500mW (8Ω, MAX) 400mW (8Ω, 10% THD)

**Narrow FM models are available depending on areas of distribution.

TX 144 ~ 147.995MHz

RX 136 ~ 173.995MHz

TX 144 ~ 145.995MHz

RX 144 ~ 145.995MHz

TX 136 ~ 173.995MHz

RX 136 ~ 173.995MHz

°C (+14 ~ 113°F)

450KHz

*144 ~ 147.995MHz

*144 ~ 145.995MHz

*150 ~ 173.995MHz

CIRCUIT DESCRIPTION

1) Receiver System

The receiver system is a double superheterodyne system with a 21.7MHz first IF and

a 450kHz second IF.

1.Front End

The received signal at frequency in the 136~173.995MHz (E version:

144~145.995MHz) range is passed through the low-pass filter (L101, L102,

L104, L118, C101, 108, C109, C110, C117, C118, C119, C123, C124, C125,

C126, C127, and C188) and tuning circuit (C255, C256, C257, C258, D120,

L138, and L139) and amplified by the RF amplifier (Q119). The signal from

Q119 is then passed through the tuning circuit (C242, C243, C244, C245,

C269, C270, C271, D117, D118, D119, L135, L136, and L137) and converted

into 21.7MHz by the mixer (Q118).

The tuning circuit, which consists of L139, L135, L136, varicaps D117, D118,

D119, and D120 is controlled by the tracking voltage from the CPU so that it is

optimized for the reception frequency. The local signal from the VCO is

passed through the buffer (Q115), and supplied to the source of the mixer

(Q118). The radio uses the lower side of the superheterodyne system.

2. IF Circuit

The mixer mixes the received signal with the local signal to obtain the sum of

and difference between them. The crystal filter (FL101, and FL102) selects

21.7MHz frequency from the results and eliminates the signal of the unwanted

frequencies. The first IF amplifier (Q121) then amplifies the signal of the

selected frequency.

3. Demodulator Circuit

After the signal is amplified by the first IF amplifier (Q121), it is input to pin 16

of the demodulator IC (IC103). The second local signal of 21.25MHz (shared

with PLL IC reference oscillation), which is oscillated by the TCXO (X102).

Then, these two signals are mixed by the internal mixer in IC103 and the result

is converted into the second IF signal with a frequency of 450kHz. The second

IF signal is output from pin 3 of IC103 to the ceramic filter (FL103), where the

unwanted frequency band of that signal is eliminated, and the resulting signal

is sent back to the IC103 through pin 5.

The second IF signal input via pin 5 is demodulated by the internal limiter

amplifier and quadrature detection circuit in IC103, and output as an audio

signal through pin 9.

4. Audio Circuit

The audio signal from pin 9 of IC103 is amplified by the AF amplifier (Q120).

The signal is then input to pin 16 of the electronic volume (IC105) for volume

adjustment, and output from pin 14. The adjusted signal is sent to the audio

power amplifier (IC104) through pin 2 to drive the speaker.

5. Squelch Circuit

The signal except for the noise component in AF signal of IC103 is cut by the

active filter inside IC. The noise component is amplified and rectified, then

converted to the DC voltage to output from pin 14 of IC103. The voltage is led

to pin 2 of CPU and compared with the setting voltage. The squelch will open if

the input voltage is lower than the setting voltage.

2) Transmitter System

1. Modulator Circuit

The audio signal is converted to an electric signal in either the internal or

external microphone, and input to the microphone amplifier (IC110). IC110

consists of two operational amplifiers; one amplifier (pins 12, 13, and 14) is

composed of pre-emphasis and IDC circuits and the other (pins 5, 6, 7, 8, 9,

and 10) is composed of a splatter filter. The maximum frequency deviation is

obtained by IC105 and input to the cathode of the varicap of the VCO, to

change the electric capacity in the oscillation circuit. This produces the

frequency modulation.

2. Power Amplifier Circuit

The transmitted signal is oscillated by the VCO, amplified by the pre-drive

amplifier (Q101) and drive amplifier (Q106), and input to the final amplifier

(Q105). The signal is then amplified by the final amplifier (Q105) and led to the

antenna switch (D101) and low-pass filter (L104, L102, L101, C119, C118,

C117, C127, C126, C125, C124, C108, and C101), where un-wanted high

harmonic waves are reduced as needed, and the resulting signal is supplied to

the antenna.

3. APC Circuit

Part of the transmission power from the low-pass filter is detected by D108,

converted to DC, and then amplified by a amplifier (IC101). The output voltage

controls the bias voltage from the source of Q105 and Q106 to maintain the

transmission power constant.

3) PLL Synthesizer System

1. PLL

The dividing ratio is obtained by sending data from the CPU (IC113) to pin 10

and sending clock pulse to pin 9 of the PLL IC ( IC101 ). The oscillated signal

from the VCO is amplified by the buffer (Q116) and input to pin 8 of IC102.

Each programmable divider in IC102 divides the frequency of the input signal

by N according to the frequency data, to generate a comparison frequency of

5 or 6.25kHz.

2. Reference Frequency Circuit

The reference frequency appropriate for the channel steps is obtained by

dividing the 21.25MHz reference oscillation (X102) by 4250 or 3400,

according to the data from the CPU (IC113). When the resulting frequency is

5kHz, channel steps of 5, 10, 15, 20, and 30kHz are used. When it is 6.25kHz,

channel steps of 12.5, 25 , and 50kHz are used.

3. Phase Comparator Circuit

The PLL (IC102) uses the reference frequency, 5 or 6.25kHz. The phase

comparator in the IC102 compares the phase of the frequency from the VCO

with that of the comparison frequency, 5 or 6.25kHz, which is obtained by the

internal divider in IC102.

4. PLL Loop Filter Circuit

If a phase difference is found in the phase comparison between the reference

frequency and VCO output frequency, the charge pump output (pin 5) of IC102

generates a pulse signal, which is converted to DC voltage by the PLL loop

filter and input to the varicap of the VCO unit for oscillation frequency control.

5. VCO Circuit

A Colpitts oscillation circuit driven by Q108 directly oscillates the desires

frequency. The frequency control voltage determined in the CPU (IC113) and

PLL circuit is input to the varicaps (D105 and D107). This change the

oscillation frequency, which is amplified by the VCO buffer (Q113) and output

from the VCO unit.

4) CPU and Peripheral Circuits

1. LCD Display Circuit

The CPU turns ON the LCD via segment and common terminals with 1/4 the

duty and 1/3 the bias, at the frame frequency is 112.5Hz.

2. Display Lamp Circuit

When the LAMP key is pressed, “L” is output form pin 67 of CPU ( IC113) to

the bases of Q140. Q140 then turn ON and the LEDs (D128 and D129) light.

3. Reset and Backup

When the power form the DC jack or external battery increases from Circuits

0V to 2.5 or more, “ H “ level reset signal is output form the reset IC (IC108) to

pin 6 of the CPU (IC113), causing the CPU to reset. The reset signal, however,

waits at 100, and does not enter the CPU until the CPU clock (X104) has

stabilized.

4. S (Signal) Meter Circuit

The DC potential of pin 12 of IC103 is input to pin 83 of the CPU (IC113),

converted from an analog to a digital signal, and displayed as the S-meter

signal on the LCD.

5. DTMF Encoder

The CPU (IC113) is equipped with an internal DTMF encoder. The DTMF

signal is output from pin 71, through IC112 (Low-pass filter), and then through

the microphone amplifier (IC110), and is sent to the varicap of the VCO for

modulation. At the same time, the monitoring tone passes through the AF

circuit and is output form the speaker.

6. TONE Encoder

The CPU (IC113) is equipped with an internal tone encoder. The tone signal

(67.0 to 250.3Hz ) is output from pin 70 of the CPU to the 21.25MHz reference

oscillation (X102) of the PLL reference oscillator.

7. DCS Encoder

The CPU (IC113) is equipped with an internal DCS code encoder. The code

(023 to 754) is output from pin 70 of the CPU to the 21.25MHz reference

oscillation (X102) of the PLL reference oscillator.

8. CTCSS, DCS Decoder

The voice band of the AF output signal from pin 9 of IC103 is cut by sharp

active filter IC111 and amplified, then led to pin 80 of CPU. The input signal is

compared with the programmed tone frequency code in the CPU. The squelch

will open when they match.

9. Clock Shift

In the unlikely event that CPU clock noise is present on a particular operating

frequency programmed into the radio, you can shift the CPU clock frequency

to avoid the CPU clock-noise. The output signal from pin 8 of the CPU turns

on Q127. Then the oscillation frequency of X104 will be shifted about 200

ppm.

Parts List

MAIN UNIT

Ref. No. Parts No. Parts name Version Ref. No. Parts No. Parts name C101 CU3535 GRM36B102K50PT C173 C102 CU3535 GRM36B102K50PT C174 C103 CU3519 GRM36CH470J50PT C175 C104 CU3535 GRM36B102K50PT C176 CU3502 GRM36CK010C50PT C105 C177 CU3535 GRM36B102K50PT C108 CU3535 GRM36B102K50PT C178 CU3513 GRM36CH150J50PT C109 CU3512 GRM36CH120J50PT C179 CU3535 GRM36B102K50PT C110 CU3505 GRM36CH040C50PT C180 CU3515 GRM36CH220J50PT C111 CU3535 GRM36B102K50PT C181 CU0119 GRM21BB30J106KE18L C112 CU3520 GRM1552C1H560JD01D C182 CU3554 GRM36B104K10PT C113 CU3535 GRM36B102K50PT C183 CU3535 GRM36B102K50PT C114 CU3503 GRM36CK020C50PT C184 CU3547 GRM36B103K16PT C115 C185 CU3535 GRM36B102K50PT C116 CU3512 GRM36CH120J50PT C186 C117 CU3513 GRM36CH150J50PT C187 CU3513 GRM36CH150J50PT C118 CU3513 GRM36CH150J50PT C188 CU3508 1005 CH 50V 7PF D C119 CU3513 GRM36CH150J50PT C189 CU3535 GRM36B102K50PT C120 C190 C122 CU3559 GRM155B30J105KE18D C191 CU3137 GRM188B31C105KA92D C123 C192 CU3535 GRM36B102K50PT C124 CU3512 GRM36CH120J50PT C193 CU3514 GRM36CH180J50PT C125 CU3512 GRM36CH120J50PT C194 CU3554 GRM36B104K10PT C126 CU3513 GRM36CH150J50PT C195 CU3535 GRM36B102K50PT C127 CU3514 GRM36CH180J50PT C196 CU3502 GRM36CK010C50PT C129 CU3512 GRM36CH120J50PT C197 CU3527 GRM1552C1E221JD01D C130 CU3514 GRM36CH180J50PT T, E, EUK C198 CU3554 GRM36B104K10PT C131 CU3517 GRM36CH330J50PT C199 CU3515 GRM36CH220J50PT C132 CU3516 GRM36CH270J50PT C200 CU3554 GRM36B104K10PT C133 CU3517 GRM36CH330J50PT C201 CU3535 GRM36B102K50PT C134 CU3513 GRM36CH150J50PT C202 CU3547 GRM36B103K16PT C135 CU3513 GRM36CH150J50PT C203 CU3535 GRM36B102K50PT C136 CU3513 GRM36CH150J50PT C204 CU3535 GRM36B102K50PT C137 CU3535 GRM36B102K50PT C205 CS0396 20V 0.1UF C138 C206 CS0396 20V 0.1UF C139 C207 CU3547 GRM36B103K16PT C140 CU3554 GRM36B104K10PT C209 CU3515 GRM36CH220J50PT T, E, EUK C141 CU3535 GRM36B102K50PT C209 CU3514 GRM36CH180J50PT TFH C142 CU3502 GRM36CK010C50PT C210 CU3505 GRM36CH040C50PT C144 C211 CU3526 GRM1552C1E181JD01D C145 CU3535 GRM36B102K50PT C212 CU3528 GRM1552C1E271JD01D C146 CU3535 GRM36B102K50PT C213 CU3526 GRM1552C1E181JD01D C147 CU3506 GRM36CH050C50PT C214 CU3535 GRM36B102K50PT C149 CU3502 GRM36CK010C50PT C215 CU3554 GRM36B104K10PT C150 CU3502 GRM36CK010C50PT C216 C151 CU3547 GRM36B103K16PT C219 CS0398 6.3V 2.2UF C152 CU3535 GRM36B102K50PT C220 CU3535 GRM36B102K50PT C153 C221 CU3535 GRM36B102K50PT C155 CU3535 GRM36B102K50PT C222 CU3535 GRM36B102K50PT C156 C223 C157 CU3535 GRM36B102K50PT C224 CU3547 GRM36B103K16PT C158 CU3535 GRM36B102K50PT C225 CU3535 GRM36B102K50PT C159 CU3547 GRM36B103K16PT C226 CU3535 GRM36B102K50PT C160 CU3535 GRM36B102K50PT C227 CU3535 GRM36B102K50PT C161 CU3535 GRM36B102K50PT C228 CU3515 GRM36CH220J50PT C162 C229 CU3515 GRM36CH220J50PT C163 CU3535 GRM36B102K50PT C230 CU3512 GRM36CH120J50PT C164 CS0441 TMCMA0J226MTRF C231 CU0119 GRM21BB30J106KE18L C165 CU3535 GRM36B102K50PT C232 CU3535 GRM36B102K50PT C166 CU3513 GRM36CH150J50PT C233 CU3522 GRM1552C1H820JD01D C167 CU3523 GRM1552C1H101JZ01D C234 CU3547 GRM36B103K16PT C168 CU3502 GRM36CK010C50PT C235 CU3519 GRM36CH470J50PT C169 CU3502 GRM36CK010C50PT C236 CU3535 GRM36B102K50PT C171 CU3511 GRM36CH100D50PT C237 CU3547 GRM36B103K16PT C172 CU3535 GRM36B102K50PT C238 CU3539 GRM36B222K50PT

Ref. No. Parts No. Parts name Version Ref. No. Parts No. Parts name C239 CU3547 GRM36B103K16PT C305 CU3138 GRM188B31C225KE14D T, E, EUK C240 CU3535 GRM36B102K50PT C306 CU3559 GRM155B30J105KE18D C241 CU3539 GRM36B222K50PT C307 CU3535 GRM36B102K50PT C242 CU3535 GRM36B102K50PT C308 CU3138 GRM188B31C225KE14D C243 CU3573 GRM1554C1HR80BZ01D C310 CU3137 GRM188B31C105KA92D C244 CU3573 GRM1554C1HR80BZ01D C311 CU3535 GRM36B102K50PT C245 CU3523 GRM1552C1H101JZ01D C312 CU3554 GRM36B104K10PT T, E, EUK C246 CU3554 GRM36B104K10PT C313 CU3137 GRM188B31C105KA92D C247 CU3554 GRM36B104K10PT C314 CU3547 GRM36B103K16PT C248 CU3559 GRM155B30J105KE18D C315 CU3547 GRM36B103K16PT C249 CU3537 GRM36B152K50PT C316 CU3554 GRM36B104K10PT C250 CU3537 GRM36B152K50PT C317 CU3517 GRM36CH330J50PT C252 CU3535 GRM36B102K50PT C318 CU3516 GRM36CH270J50PT C253 CU3543 GRM36B472K25PT C319 C254 CU3549 1005 B 16V 0.015UF K C320 CU3535 GRM36B102K50PT C255 CU3535 GRM36B102K50PT C321 CU3535 GRM36B102K50PT C256 CU3516 GRM36CH270J50PT C322 CU3559 GRM155B30J105KE18D C257 CU3505 GRM36CH040C50PT C323 CU3535 GRM36B102K50PT C258 CU3523 GRM1552C1H101JZ01D C324 CU3559 GRM155B30J105KE18D C259 C325 CU3554 GRM36B104K10PT C260 CU3554 GRM36B104K10PT C326 C261 CU3547 GRM36B103K16PT C327 CU3137 GRM188B31C105KA92D C262 CU3535 GRM36B102K50PT C328 CU3535 GRM36B102K50PT C263 CU3508 1005 CH 50V 7PF D T, E, TFH C329 CU3554 GRM36B104K10PT C263 CU3513 GRM36CH150J50PT EUK C330 CU3535 GRM36B102K50PT C264 CU3535 GRM36B102K50PT C331 CU0119 GRM21BB30J106KE18L C265 CE0436 16CE47BSS C332 CU3535 GRM36B102K50PT C266 CU3137 GRM188B31C105KA92D C333 CU3535 GRM36B102K50PT C267 CU3535 GRM36B102K50PT C334 CU0119 GRM21BB30J106KE18L C268 CU3535 GRM36B102K50PT C335 CU3540 GRM36B272K50PT C269 CU3523 GRM1552C1H101JZ01D C336 CU3523 GRM1552C1H101JZ01D C270 CU3523 GRM1552C1H101JZ01D C337 CU3535 GRM36B102K50PT C271 CU3523 GRM1552C1H101JZ01D C338 CU3137 GRM188B31C105KA92D C272 CU3535 GRM36B102K50PT C339 CU3137 GRM188B31C105KA92D C273 CU3547 GRM36B103K16PT C340 CU3535 GRM36B102K50PT C274 CU3554 GRM36B104K10PT C341 CU3547 GRM36B103K16PT C275 CU3535 GRM36B102K50PT C342 CU3547 GRM36B103K16PT C276 CU3523 GRM1552C1H101JZ01D C343 CU3554 GRM36B104K10PT C277 CU3535 GRM36B102K50PT C344 CU3554 GRM36B104K10PT C278 CU3523 GRM1552C1H101JZ01D C345 CU3554 GRM36B104K10PT C279 CU3547 GRM36B103K16PT C346 CU3547 GRM36B103K16PT C280 CS0441 TMCMA0J226MTRF C347 CU3523 GRM1552C1H101JZ01D C281 CU3535 GRM36B102K50PT C348 CU3547 GRM36B103K16PT C282 CU3554 GRM36B104K10PT C349 CU3539 GRM36B222K50PT C284 CU3559 GRM155B30J105KE18D C350 CU3533 GRM36B681K50PT C285 CU3554 GRM36B104K10PT C351 C286 CU3527 GRM1552C1E221JD01D C352 CU3547 GRM36B103K16PT C287 CU3535 GRM36B102K50PT C353 CU3539 GRM36B222K50PT C288 CU3527 GRM1552C1E221JD01D C354 CU3541 GRM36B332K50PT C289 CU3535 GRM36B102K50PT C355 CU3547 GRM36B103K16PT C290 CU3554 GRM36B104K10PT C356 CU3535 GRM36B102K50PT C291 CU3138 GRM188B31C225KE14D C357 CU3535 GRM36B102K50PT C292 CE0436 16CE47BSS C358 CU0119 GRM21BB30J106KE18L C293 CU3554 GRM36B104K10PT C359 CU3553 GRM36B473K10PT C294 CU3535 GRM36B102K50PT C360 CU3559 GRM155B30J105KE18D C295 C361 CU3535 GRM36B102K50PT C296 CE0463 10CE100BSS C362 CU3533 GRM36B681K50PT C297 C363 CU3535 GRM36B102K50PT C298 CU3535 GRM36B102K50PT C364 CU3539 GRM36B222K50PT C299 CU3137 GRM188B31C105KA92D C365 CU3533 GRM36B681K50PT C300 CU3554 GRM36B104K10PT C366 CU3537 GRM36B152K50PT C301 CU3535 GRM36B102K50PT C367 CU3523 GRM1552C1H101JZ01D C302 CE0462 6CE100BSS C368 CU3531 GRM36B471K50PT C303 CU3535 GRM36B102K50PT C369 CU3541 GRM36B332K50PT C304 CU3554 GRM36B104K10PT C370 CU3554 GRM36B104K10PT

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