BENISON FB-388

BENISON

FB-388

VHF FM TRANSCEIVERS

Service Manual

2006-1-28

- 1 -

BENISON FB-388

SPECIFICATIONS

GENERAL

. Frequency coverage

. Type of emission

. Number of channels

. Power supply requirement

. Current drain (approx.)

. Frequency stability

. Usable temperature range

. Dimensions (projections not included)

. Weight (with ant., BP-512)

: 144.0000-145.9875MHz

: FM(FE3)

: 99ch

: 7.4 V DC (negative ground; supplied battery pack)

: Transmit at High (4.0 W) 1.8 A, at Low (1.0 W) 700 mA

: Receive rated audio 250 mA

: stand-by 70 mA

: ±0.001 %

: -10°C～+60°C

: 54(W)×112(H)×35(D) mm

: 350 g

TRANSMITTER

. RF output power (at 7.4 V DC)

. Modulation system

. Maximum frequency deviation

. Spurious emissions

. Adjacent channel power

. Transmitter audio distortion

: 4 W / 1 W (High / Low)

: Variable reactance frequency modulation

: ±2.5 kHz

: 70 dB typical

: 60 dB typical

: Less than 3% at 1 kHz, 40% deviation

RECEIVER

3

4

1

2

5

6

7

8

9

10

. Receive system

. Intermediate frequencies

. Sensitivity

. Squelch sensitivity

. Adjacent channel selectivity

. Spurious response rejection

. Intermodulation rejection ratio

. Hum and noise

. Audio output power (at 7.4 V DC)

: Double conversion superheterodyne system

: 1st 38.850 MHz / 2nd 450 kHz

: 0.18 µ V at 12 dB SINAD (typical)

: 0.25 µ V at threshold (typical)

: 65 dB (typical)

: 70 dB (typical)

: 70 dB (typical)

: 40 dB (typical)

All stated specifications are subject to change without notice or obligation.

50 CTCSS TONES SQ. ( Hz )

NO. TONE NO. TONE NO. TONE NO. TONE NO.

67.0

69.3

71.9

74.4

77.0

79.7

82.5

85.4

88.5

91.5

11

12

13

14

15

16

17

18

19

20

94.8

97.4

100.0

103.5

107.2

110.9

114.8

118.8

123.0

127.3

21

22

23

24

25

26

27

28

29

30

131.8

136.5

141.3

146.2

151.4

156.7

159.8

162.2

165.5

167.9

31

32

33

34

35

36

37

38

39

40

171.3

173.8

177.3

179.9

183.5

186.2

189.9

192.8

196.6

199.5

41

42

43

44

45

46

47

48

49

50

TONE

203.5

206.5

210.7

218.1

225.7

229.1

233.6

241.8

250.3

254.1

- 2 -

BENISON FB-388

CONTROL AND CONNECTIONS

1. CONTROL DIAL

2. VOLUME CONTROL /POWER SWITCH

3. PTT BUTTON

4. INTERNAL MICROPHONE

5. FUNCTION BUTTON

6. SQL BUTTON

7. KEY PAD

8. FUNCTION DISPLAY

9. MIC JACK

10. SP JACK

11. INTERNAL SPEAKER

12. ANTENNA

13. TX INDICATOR

- 3 -

BENISON FB-388

CIRCUIT DESCRIPTION

1) Receiver System

The receiver system is a double superheterodyne system with a 38.85MHz first IF and a 450kHz second

IF.

1. Front End

The received signal at any frequency in the 144.0000MHz to 145.9875MHz range is passed through the low-pass filter (L39, L38, L37, C159,C158, C122,C157,C121,C156 and C154) and tuning circuit (L19 and

C203), and amplified by the RF amplifier (Q29). The signal from Q29 is then passed through the tuning circuit (L28.L27.L26) and converted into 38.85MHz by the mixer (Q28). The local signal from the VCO is passed through the buffer (Q34), and supplied to the source of the mixer (Q28). 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 (FL3, FL2) selects 38.850MHz frequency from the results and eliminates the signals of the unwanted frequencies. The first IF amplifier (Q17) then amplifies the signal of the selected frequency.

3. Demodulator Circuit

After the signal is amplified by the first IF amplifier (Q36), it is input to pin 16 of the demodulator IC (IC14).

The second local signal of 38.4MHz, which is oscillated by the internal oscillation circuit in IC14 and crystal

(X6), Then these two signals are mixed by the internal mixer in IC14 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 IC14 to the ceramic filter (FL1), where the unwanted frequency band of that signal is eliminated, and the resulting signal is sent back to the IC14 through pins 5.The second IF signal input via pin 5 is demodulated by the internal limiter amplifier and quadrature detection circuit in IC14, and output as an audio signal through pin

9.

4. Audio Circuit

AF signals from the FM IF IC (IC14, pin 9) via the AF filter circuit (IC3, pins 12,13). The output signals from pin 14 are applied to the mute switch (Q16), are applied to the AF power amplifier (IC9, pin 4) after being passed through the [VOL] control (W2).The applied AF signals are amplified at the AF power amplifier circuit (IC1, pin 4) to obtain the specified audio level. The amplified AF signals, output from pin 10, are applied to the internal speaker (SP1) as the “SP” signal via the [SP-J] jack when no plug is connected to the jack.

5. Squelch Circuit

A squelch circuit cuts out AF signals when no RF signals are received. By detecting noise components in the AF signals,A portion of the AF signals from the FM IF IC (IC14, pin 9) are applied to the squelch switches (Q19.20.21.22),the active filter section (IC14, pin 8) where noise components are amplified and detected with an internal noise detector.The active filter section amplifies noise components. The filtered signals are rectified at the noise detector section and converted into “SQI” signals at the noise comparator section. The “SQI” signal is applied to the CPU(IC8, pin 22). The CPU detects the receiving signal , and outputs an “AFB” signal from pin 39. This signal controls the mute switch (Q16) to cut the AF signal line.

2) Transmitter System

1.

MICROPHONE AMPLIFIER CIRCUIT

The microphone amplifier circuit amplifies audio signals with +6 dB/octave pre-emphasis characteristics from the microphone to a level needed for the modulation circuit. The AF signals from the microphone are applied to the microphone amplifier circuit (IC2C, pin 2). The amplified AF signals are passed through the low-pass filter circuit (IC1B, pins 5, 6). The filtered AF signals are applied to the modulator circuit after being passed through the modulation circuit.

- 4 -

BENISON FB-388

2.

MODULATION CIRCUIT

The modulation circuit modulates the VCO oscillating signal (RF signal) using the microphone audio signal.

The audio signals change the reactance of a diode (D29) to modulate an oscillated signal at the VCO circuit (Q30).The oscillated signal is amplified at the buffer-amplifiers (Q31,Q32,Q33,Q35),.

3.

DRIVE/POWER AMPLIFIER CIRCUITS

The signal from the VCO circuit passes through the buffer (Q31,Q32,Q33,Q35),drive (Q27)and power amplifier (Q26)to obtain 4W of RF power (at 7.4V DC). The amplified signal passes through the antenna switching circuit (D11), and low-pass filter and is then applied to the antenna connector. The bias current of the drive (IC6) and the power amplifier (Q26) is controlled by the APC circuit.

4. APC CIRCUIT

The APC circuit (IC6) protects the drive and the power amplifiers from excessive current drive, and selects

HIGH or LOW output power. The signal output from the power detector circuit (L32,R177,RR95,RR144) is applied to the differential amplifier (IC6, pin 2.3), and the “PWC” signal from the expander (IC6, pin5), controlled by the CPU (IC8), is applied to the other input for reference. When the driving current is increased, input voltage of the differential amplifier (pin 2) will be increased. In such cases the differential amplifier output voltage (pin 7) is decreased to reduce the driving current.

3) PLL Synthesizer Circuit

1. PLL

The dividing ratio is obtained by sending data from the CPU (IC8) to pin 14 and sending clock pulses to pin

15 of the PLL IC (IC13). The oscillated signal from the VCO is amplified by the buffer (Q31,Q34) and input to pin6 or pin11 of IC13. Each programmable divider in IC13 divides the frequency of the input signal by N according to the frequency data, to generate a comparison frequency.

2. 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 (pin8,pin9) of IC13 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.

3. VCO Circuit

A PLL circuit provides stable oscillation of the transmit frequency and receive 1st frequency. The PLL output compares the phase of the divided VCO frequency to the reference frequency. The PLL output frequency is controlled by the divided ratio (N-data) of a programmable divider.The PLL circuit contains the VCO circuit (Q25, Q30). The oscillated signal is amplified at the buffer-amplifiers (Q34, Q31) and then applied to the PLL IC (IC13). The PLL IC contains a prescaler, programmable counter, programmable divider and phase detector, etc. The entered signal is divided at the prescaler and programmable counter section by the N-data ratio from the CPU. The divided signal is detected on phase at the phase detector using the reference frequency. If the oscillated signal drifts, its phase changes from that of the reference frequency, causing a lock voltage change to compensate for the drift in the oscillated frequency. A portion of the VCO signal is amplified at the buffer-amplifier (Q34, Q31) and is then applied to the receive 1st mixer (Q28) or transmit buffer-amplifier circuit (Q32).

4) CPU and Peripheral Circuits

1. LCD Display Circuit

The IC10 turns ON the LCD via segment and common terminals with 1/4 the duty and 1/3 the bias, at the frame frequency is 100Hz.

2. Display Lamp Circuit

When the key is pressed, “H” is output form pin 24 of CPU (IC8) to the bases of Q2. Q2 then turn ON and the LED (D1.2.4.5.7.8) light.

3. DTMF Encoder

The CPU (IC8) is equipped with an internal DTMF encoder. The DTMF signalis output from pin 8, through

- 5 -

BENISON FB-388

C60, and through the microphone amplifier (IC2), 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.

4. CTCSS Encoder

The IC3 is equipped with an internal tone encoder, The tone signal (67.0 to 254.3Hz) is output from pin 18 of the IC3 to the varicap (D29) of the VCO for modulation.

5. CTCSS Decoder

.

The voice band of the AF output signal from pin 9 of IC14 is cut by sharp active filter IC3 and amplified.

The input signal is compared with the programmed tone frequency code in the CPU. The squelch will open when they match.

- 6 -

BENISON FB-388

ADJUSTMENT PROCEDURES

Note:

It is assumed that the unit is supplied with a regulated 8.0 volts during the adjustment procedure. Do not use a metal screw driver to adjust the ferrite cores as it causes variations in the inductance whilst adjustments are being performed. Use of the wrong size trimming tools can cause damage to the cores. A plastic or ceramic trimming tool is recommended.

ADJUSTMENT

1) Required Test Equipment

The following items are required to adjust radio parameters:

1. Regulated power supply

Supply voltage: 5~14V DC

Current: 3A or more

2. Digital multimeter

Voltage range: FS = Approx. 20V

Current: 10A or more

Input resistance: High impedance

3. Oscilloscope

Measurable frequency: Audio frequency

4. Audio dummy load

Impedance: 8 ohm

Dissipation: 1W or more

Jack: 3.5mm

5. SSG

Output frequency: 200MHz or more

Output level: -20dBu/0.1uV ~120dBu/1V

Modulation: FM

6. Spectrum Analyzer

Measuring range: Up to 2GHz or more

7. Power meter

Measurable frequency: Up to 200MHz

Impedance: 50, unbalanced

Measuring range: 0.1W ~10W

8. Audio volmeter

Measurable frequency: Up to 100kHz

Sensitivity: 1mV to 10V

9. Audio generator

Output frequency: 67Hz to 10kHz

Output impedance: 600, unbalanced

10.Distortion meter/SINAD meter

Measurable frequency: 1kHz

Input level: Up to 40dB

Distortion: 1% ~100%

- 7 -

BENISON FB-388

11.Frequency counter

Measurable frequency: Up to 200MHz

Measurable stability: Approx. ±0.1ppm

12.Linear detector

Measurable frequency: Up to 200MHz

Characteristics: Flat

CN: 60dB or more

Note

Standard modulation: 1kHz ±2.5kHz/DEV

Reference sensitivity: 12dB SINAD

Specified audio output level: 200mW at 8

Adjustment Mode

High power adjustment mode

1. At same time push [3] key and [9] key.

Rotate [VOL] to the power ON.

2. Then press [7] key,

3. Press the [6] or [9] key set the output power to the value closest to 4 W .

4. When the PTT key is released, the output power at that time will be stored as the high power setting.

5. Press the SQL key to return.

Low power adjustment mode

1. At same time push [3] key and [9] key.

Rotate [VOL] to the power ON.

2. Then press [8] key,

3. Press the [6] or [9] key set the output power to the value closest to 1 W .

4. When the PTT key is released, the output power at that time will be stored as the low power setting.

5. Press the SQL key to return.

Modulation Adjustment

STEP

1

2

3

CONDITIONS

Connect the antenna output via a suitable RF attenuator to a modulation analyzer

Apply 1000Hz at a level of 5.0mV to the microphone jack

Press the PTT switch

ADJUST

━

━

W1

READINGS

━

━

4 Increase the modulation signal level to 50mV

W1

Modulation analyzer reading 1.5kHz

(+/-0.2KHz)

Modulation analyzer reading 2.5kHz

(+/-0.1KHz)

- 8 -

BENISON FB-388

Frequency Adjustment

STEP

1

2

CONDITIONS

Connect the antenna output via a suitable RF attenuator to a

Frequency counter

Press the PTT switch

ADJUST

━

W3

READINGS

━

Frequency counter: +/-0.2KHz

SERVICING AND REPAIR

RF RECEIVE CIRCUITS

1. Ensure that the transceiver has not been switched to the battery saving mode.

2. Carefully check that all connectors are in a good condition. Check that the power supply voltage(IC5) of the receiver circuit is approximately 4.5-5.0V.

3. If the correct gain is measured then check that the bias of Q25 or Q30 is Vs=1V and Vd=4.2V. Check the signal level at the collector of Q31 or Q34 the local oscillator output, the signal level should be around -10dBm and the spectrum purity should be good.

TRANSMIT CIRCUIT

1. Carefully check that all connectors are in good condition and check that the power supply voltage is correct.

2. Using the frequency counter to check that the operating frequency is correct. If not, check whether the

PLL is locked. If the PLL is unlocked, check the local oscillator circuit. If the PLL is locked, check that the RF output is correct. If not, check from Q31 Q32 Q33 Q35 Q27 Q26 stage by stage to assure that the signal levels are correct. First check the bias voltage of each stage and then try to find any voltages which are out of tolerance.

VOLTAGE REGULATION CIRCUIT

Apply 8.0 volts to the power input jack, Measure the collector voltage of IC5. The normal value should be approximately 5.0 volts. The voltage at the collector of IC5 should hold are approximately 5.0 volts.

AUDIO OUTPUT

1. Connect a signal generator set to the required frequency at an output level of 1mV, deviated with a

1kHz tone and 1.5kHz deviation to the antenna socket. Connect a probe to pin 9 (the output pin) of

IC14. If the transceiver is operating correctly a 1kHz sine wave should be present.

2. If not, then use the oscilloscope to check the second local oscillator to assure that it is operating correctly. A probe connected to the case of X3 or pin 16 of IC13 should detect the presence of a

- 9 -

BENISON FB-388

38.4MHz sine wave. If not, then X6 may have failed.

3. If a 1kHz signal is measured at pin 9 of IC14 then decrease the output level of the signal generator to

0.35uV. If the 1kHz audio signal disappears when the RF level is decreased to this level, then IC14 may be faulty.

4. If IC14 appears okay, then check IC1 are correct. Check for the presence of a 1kHz audio signal at the collector of the pin10.

5. Check pin 14 of IC3 to see if there is a 1kHz audio signal present. Check pin 10 of IC1 for a presence of a large 1kHz audio signal. If the audio output signal is too small or not present then IC1 may be faulty.

CONTROL PROBLEM

If the LCD display becomes faulty then check the drive IC10 .

- 10 -

BENISON FB-388

PARTS LIST

Part Type

C32

C33

C34

C35

C36

C37

C38

C26

C27

C28

C29

C30

C31

C39

C40

C41

C42

C43

C44

C7

C8

C9

C10

C11

C12

C13

C1

C2

C3

C4

C5

C6

C14

C15

C16

C17

C18

C19

C20

C22

C23

C24

C25

Designator Footprint

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

- 11 -

C84

C85

C86

C87

C88

C89

C90

C91

C73

C74

C75

C76

C77

C78

C79

C80

C81

C82

C83

C59

C60

C61

C62

C63

C64

C51

C52

C53

C54

C55

C56

C57

C58

C65

C66

C67

C69

C70

C71

C72

BENISON FB-388

C45

C46

C47

1000P

1000P

1000P

C48

C49

C50

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.1

100P

1000P

1000P

15P

10U

10U

10U

10U

10U

10U

10U

10U

10U

10U

10U

100P

100P

100P

100P

100P

100P

100P

- 12 -

C130

C131

C132

C133

C134

C135

C136

C137

C119

C120

C121

C122

C123

C124

C125

C126

C127

C128

C129

C98

C99

C100

C101

C102

C103

C104

C105

C106

C107

C108

C109

C110

C111

C112

C113

C114

C115

C116

C117

C118

BENISON FB-388

C92

C93

C94

100P

100P

100P

C95

C96

C97

100P

100P

0.1

0.1

0.1

0.1

0.1

0.1

0.1

0.1

0.1

0.1

0.1

0.1

0.1

0.1

0.1

0.1

0.047

0.047

0.047

22P

22P

22P

22P

22P

22P

22P

5600P

5600P

0.022

220P

220P

220P

220P

1U

1U

1U

1U

1U

180P

200P

10U

- 13 -

C177

C178

C179

C180

C181

C182

C183

C184

C166

C167

C168

C169

C170

C171

C172

C173

C174

C175

C176

C145

C146

C147

C148

C149

C150

C151

C152

C153

C154

C155

C156

C157

C158

C159

C160

C161

C162

C163

C164

C165

BENISON FB-388

C138

C140

C141

1U

0.22

0.22

C142

C143

C144

0.22

0.22

0.22

0.22

100U

100U

22U

1U

1U

10P

10P

10P

10P

10P

10P

10P

10P

470P

470P

470P

470P

470P

470P

8200P

470P

470P

470P

10U

10U

0.1U

0.1U

102P

47P

47P

4.7U

4.7U

17P

1P

1P

1P

15P

12P

12P

- 14 -

C223

C224

C225

C226

C227

C228

C229

C230

C212

C213

C214

C215

C216

C217

C218

C219

C220

C221

C222

C191

C192

C193

C194

C195

C196

C197

C198

C199

C200

C201

C202

C203

C204

C205

C206

C207

C208

C209

C210

C211

BENISON FB-388

C185

C186

C187

12P

12P

12P

C188

C189

C190

12P

12P

12P

0.5P

0.5P

82P

8P

18P

18P

18P

18P

5P

4P

4P

7P

9P

20P

20P

33P

0.01

1000P

1000P

1000P

1000P

100P

100P

100P

100P

0.1

0.01

0.01

22U

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

1000P

100P

- 15 -

BENISON FB-388

D19

D20

D21

D22

D23

D24

D25

D26

D27

D28

D29

D13

D14

D15

D16

D17

D18

D5

D6

D7

D8

D9

D10

D11

D12

Part Type

D1

D2

D3

D4

Part Type

FL1

FL2

FL3

Part Type

IC1

IC2

IC3

IC4

IC5

IC6

IC8

IC10

Designator Footprint

LED_Y

LED_Y

1SS372

LED_Y

LED_Y

A111

LED_Y

LED_Y

A111

A111

1SS356

HS277

1SS356

A111

A111

A111

A111

A111

A111

A111

LED_G

LED_R

N

3V

HVC375

HVC375

HVC375

HVC375

BB149

Designator Footprint

LTC450E

38.85M

38.85M

Designator Footprint

TA7368F

NJM2902V

CMX808

24WC08

XC6202P502

NJM2904

EM78P567

HT1621B

- 16 -

BENISON FB-388

IC13

IC14

M64082

TA31136

Part Type

J1

J2

J3

J4

J5

Designator Footprint

JACK (MIC)

SMD14P

ANT JACK

SMD14P

SP-J

Part Type

K1

K2

K3

K4

K5

L23

L24

L25

L26

L27

L28

L29

L30

L12

L13

L14

L15

L16

L17

L18

L19

L20

L21

L22

Part Type

L1

L2

L3

L5

L6

L7

L8

L9

L11

Designator Footprint

FUNC

MONI

PTT

RTW

POWER SW

470N

102T

102T

7T

7T

7T

7T

7T

180N

2.2UH

2.2UH

2.2UH

2.2UH

100N

100N

100N

100N

68N

470N

Designator Footprint

102T

102T

102T

102T

102T

102T

102T

10UH

150N

- 17 -

BENISON FB-388

L31

L32

L33

1UH

9T

301T

L34

L35

L36

3T

2T

2.2UH

L37

L38

L39

L40

4T

5T

5T

6T

Q17

Q18

Q19

Q20

Q21

Q22

Q23

Q24

Q25

Q26

Q27

Q28

Q29

Q30

Q31

Q32

Q33

Q36

Q10

Q11

Q12

Q13

Q14

Q15

Q16

Q3

Q5

Q6

Q7

Q8

Q9

Part Type

Q1

Q2

Part Type

Designator Footprint

5B1

2SC2712

2SC2712

DTA114

DTA114

DTA114

DTA114

DTA114

DTA114

DTA114

DTA114

5B1

5B1

2SK1588

DTA114

DTA114

DTA114

DTA114

DTA114

DTA114

DTA114

K52

R007

DUR

DUR

K52

R24

R24

R24

2SC4617

2SC4617

2SK2973

2SC5195

Designator Footprint

- 18 -

R39

R40

R41

R42

R43

R44

R45

R46

R28

R29

R30

R31

R32

R33

R34

R35

R36

R37

R38

R15

R16

R17

R18

R19

R20

R7

R8

R9

R10

R11

R12

R13

R14

R21

R22

R23

R24

R25

R26

R27

BENISON FB-388

R1

R2

R3

47K

47K

47K

R4

R5

R6

47K

47K

47K

47K

47K

47K

47K

47K

47K

47K

220

220

330

330

330

330

330

330

330

10K

10K

10K

10K

10K

10K

10K

10K

10K

10K

10K

10K

10K

10K

4K7

4K7

4K7

4K7

560

560

560

560

100

100

- 19 -

R85

R86

R87

R88

R89

R90

R91

R92

R74

R75

R76

R77

R78

R79

R80

R81

R82

R83

R84

R61

R62

R63

R64

R65

R66

R53

R54

R55

R56

R57

R58

R59

R60

R67

R68

R69

R70

R71

R72

R73

BENISON FB-388

R47

R48

R49

100

100

100

R50

R51

R52

100

100

100

100

100

100

100

100

100

470

470

470

470

2K

2K

15K

3K3

3K3

3K3

3K3

3K3

3K3

T10K

15K

3K3

0

0

0

0

0

0

0

0

0

0

2K7

2K7

100K

100K

100K

100K

100K

100K

- 20 -

R131

R132

R133

R134

R135

R136

R137

R138

R120

R121

R122

R123

R124

R125

R126

R127

R128

R129

R130

R99

R100

R101

R102

R103

R104

R105

R106

R107

R108

R109

R110

R111

R112

R113

R114

R115

R116

R117

R118

R119

BENISON FB-388

R93

R94

R95

100K

100K

100K

R96

R97

R98

100K

100K

100K

1K

1K

1K

1K

1K

1K

1K

1K

1K

1K

1K

1K

1K

1K

1K

1K

1K

1K

1K

1K

1K

220K

220K

220K

220K

330K

330K

10

47

33K

0

2K

120K

33K

10

10

22K

22K

470K

1M

- 21 -

R177

R178

R179

R180

R181

R182

R183

R184

R166

R167

R168

R169

R170

R171

R172

R173

R174

R175

R176

R145

R146

R147

R148

R149

R150

R151

R152

R153

R154

R155

R156

R157

R158

R159

R160

R161

R162

R163

R164

R165

BENISON FB-388

R139

R140

R141

1M

1M

1M

R142

R143

R144

68K

180K

180K

180K

180K

3K9

3K9

3K9

1K5

1K5

1K8

47

47

22

22

6K8

2K2

2K2

2K2

20K

33K

33K

10K

10K

10K

47K

47K

100

3K3

680

680

2K2

47

47

82K

220

220

56K

82K

150K

330K

180K

180K

- 22 -

BENISON FB-388

R185 180K

X1

X2

X3

X5

X6

Part Type

MC1

SP1

W1

W2

W3

Designator Footprint

MIC(-58dB)

8ohm

W50K

10K

50K

4M

32.768K

16.8M

C24

38.4M

- 23 -

BENISON FB-388

MEMO

- 24 -

PTT

R5C

T5C

SQI