Rotel RT-955 Service manual

Quality Uncompromised

®

Technical

Manual

Table of Contents

Specification......................................1

Parts List ...........................................2~5

Adjustment........................................6~12

PCB Assembly ..................................13~15

Schematic Diagram ..........................16~22

Specification

FM Tuner

Usable Sensitivity: 12.2 dBf 50dB Quieting Sensitivity: 20.2 dBf (mono)

Signal to Noise Ratio (at 65 dBf): 75 dBf (mono)

Harmonic Distortion (at 65 dBf): 0.2 % (mono)

Frequency Response: 10 Hz - 15 kHz, ± 3 dB Capture Ratio: 2.0 dB Alternate Channel Selectivity: 47 dB (± 400 KHz) Spurious Response Ratio: 90 dB Image Rejection Ratio: 80 dB IF Rejection Ratio: 80 dB AM Suppression Ratio: 55 dB Stereo Separation (100Hz/1 KHz/10 KHz): 40 dB/45 dB/35 dB Output level: 1.2V Antenna Input: 75 ohms unbalanced

AM Tuner

Usable Sensitivity: 300 μV/m Selectivity: 25 dB Harmonic Distortion : 0.5 % Image Rejection Ratio: 45 dB Signal to Noise Ratio: 48 dB Output level: 165 mV Antenna Input: Loop Antenna

General

Power Consumption: 10 Watts Power Requirements (AC): 120 volts, 60 Hz (USA version)

Weight: 3.7 kg/8.2 lb. Dimensions (W x H x D): 440 x 72 x 286 mm

AM/FM STEREO TUNER

RT-955

45.3 dBf (stereo)

72 dBf (stereo)

0.3 % (stereo)

230 volts, 50 Hz (European version)

173/8" x 27/8" x 111/4"

SHINSEN-BLD. 4F 10-10 SHINSEN-CHO, SHIBUYA-KU, TOKYO 150-0045, JAPAN

Serial. NO. Beginning

Y-329A-00065C/S-S

Parts List-1

SYMBOL PARTS NO. DESCRIPTION SYMBOL PARTS NO. DESCRIPTION

X-1273-01 PCB ASSEMBLY

ANT200 ANT201 C201.202 C203 C204

ANTENNA TERMINAL 1P ANTENNA TERMINAL 3P

0.01UF

0.022UF 100UF/16V

ANTENNA-A ANTENNA-B CERAMIC CAPACITOR CERAMIC CAPACITOR ELECTRIC CAPACITOR

C304 C306-308 C309 C311.312 C313

0.047UF

0.022UF 220PF

0.022UF 47UF/16V

CERAMIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR ELECTRIC CAPACITOR

C205.206 C207-210 C211.212 C213 C214

C215 C216 C217 C218 C219

C221 C222 C223-236 C237 C238-241

C242 C243 C245.246 C247 C248

C249 C250.251 C252 C253 C254

33PF-CH 1000PF

0.022UF

0.01UF

3.3UF/50V

0.022UF 100UF/16V

0.022UF 47UF/16V

0.022UF

0.022UF 47UF/16V

0.022UF 100PF

0.047UF

150PF

0.022UF

0.022UF 1UF/50V

0.022UF

1UF/50V

0.022UF 100UF/16V

0.022UF 1UF/50V

CERAMIC CAPACITOR(CH TYPE) CERAMIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR ELECTRIC CAPACITOR

CERAMIC CAPACITOR ELECTRIC CAPACITOR CERAMIC CAPACITOR ELECTRIC CAPACITOR CERAMIC CAPACITOR

CERAMIC CAPACITOR ELECTRIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR

CERAMIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR ELECTRIC CAPACITOR CERAMIC CAPACITOR

ELECTRIC CAPACITOR CERAMIC CAPACITOR ELECTRIC CAPACITOR CERAMIC CAPACITOR ELECTRIC CAPACITOR

C314 C316 C317 C318 C319

C321 C322 C323.324 C325 C326

C327 C328 C329 C330 C401

C402-404 C405.406 C407.408 C409 C411

C412 C413 C414 C415.416 C417

0.022UF 1000PF

0.047UF-M

0.056UF-M

0.022UF

100UF/16V

0.01UF

0.022UF

3.3UF/50V

4.7UF/50V

1UF/50V 470PF

0.047UF

0.022UF-M

0.022UF

47UF/16V

0.0033UF

0.01UF 10UF/50V

4.7UF/50V

10UF/50V

4.7UF/50V

0.022UF-M

0.0033UF-M

0.0068UF-M

CERAMIC CAPACITOR CERAMIC CAPACITOR MYLAR CAPACITOR MYLAR CAPACITOR CERAMIC CAPACITOR

ELECTRIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR ELECTRIC CAPACITOR ELECTRIC CAPACITOR

ELECTRIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR MYLAR CAPACITOR CERAMIC CAPACITOR

ELECTRIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR ELECTRIC CAPACITOR ELECTRIC CAPACITOR

ELECTRIC CAPACITOR ELECTRIC CAPACITOR MYLAR CAPACITOR MYLAR CAPACITOR MYLAR CAPACITOR

C255 C257 C259 C260 C261

C262 C263 C264.265 C266 C267

C268.269 C270 C271 C272 C273

C274 C275 C276 C278.279 C280

C281 C282-284 C285 C301 C302

0.047UF

0.022UF

0.047UF 680PF

0.47UF/50V

1UF/50V

0.047UF 1UF/50V

0.01UF

0.022UF

0.47UF/50V

4.7UF/50V

0.047UF

0.01UF

0.022UF

10UF/50V 68PF 330PF 10UF/50V 270PF

33UF/35V 100UF/16V

0.022UF 470PF-POLY 18PF-CH

CERAMIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR ELECTRIC CAPACITOR

ELECTRIC CAPACITOR CERAMIC CAPACITOR ELECTRIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR

ELECTRIC CAPACITOR ELECTRIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR

ELECTRIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR ELECTRIC CAPACITOR CERAMIC CAPACITOR

ELECTRIC CAPACITOR ELECTRIC CAPACITOR CERAMIC CAPACITOR FILM CAPACITOR CERAMIC CAPACITOR(CH TYPE)

C501 C502 C503 C504 C505

C506.507 C508 C509 C511 C512

C513.514 C515 C516 CL201.202 CL203

CL204 CL271 CL273 CL277 CR201.202

CR203 CR204 CR271 CR273 CR277

3300UF/35V 47UF/50V

0.068UF-M

4.7UF/50V

0.068UF-M

0.022UF 10UF/50V

0.022UF 47UF/16V 220UF/16V

47UF/16V 47UF/35V

2.2UF/50V 22UF/16V

0.0039UF-M

1000PF 270PF 120PF 100PF 22UF/16V

0.0039UF-M 1000PF 270PF 120PF 100PF

ELECTRIC CAPACITOR ELECTRIC CAPACITOR MYLAR CAPACITOR ELECTRIC CAPACITOR MYLAR CAPACITOR

CERAMIC CAPACITOR ELECTRIC CAPACITOR CERAMIC CAPACITOR ELECTRIC CAPACITOR ELECTRIC CAPACITOR

ELECTRIC CAPACITOR ELECTRIC CAPACITOR ELECTRIC CAPACITOR ELECTRIC CAPACITOR MYLAR CAPACITOR

CERAMIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR ELECTRIC CAPACITOR

MYLAR CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR

2

Parts List-2

SYMBOL PARTS NO. DESCRIPTION SYMBOL PARTS NO. DESCRIPTION

CF201.202 CF203 CF204 CF205 CF301

D201 D202-205 D208 D209-212 D301.302

D303-305 D307.308 D401 D501-505 D506

D507 D508 D509 D510 D511

F501.502 FFE200 IC201 IC202 IC203

FM FILTER 10.7MM-A FM FILTER 10.7MJA10-A FM FILTER 10.7MM-A CSB456F11 SFPS450H

1N4004 1N4148 ZENER 5.1V 1N4148 KV1236Z

1N4148 1N4148 ZENER 5.1V 1N4004 ZENER 30V

ZENER 6.2V ZENER 12V 1N4148 ZENER 5.6V 1N4004

036 5ST500 FTA4-460H LC72191M LA1235 LA1235

FM IF CERAMIC FILTER FM IF CERAMIC FILTER FM IF CERAMIC FILTER CERAMIC RESONATOR FILTER FOR AM

SWITCHING DIODE SWITCHING DIODE ZENER DIODE SWITCHING DIODE VARACTOR DIODE

SWITCHING DIODE SWITCHING DIODE ZENER DIODE SWITCHING DIODE ZENER DIODE

ZENER DIODE ZENER DIODE SWITCHING DIODE ZENER DIODE SWITCHING DIODE

MINI FUSE 250V T500MA FM FRONT-END PLL IC SIGNAL METER IC FM IF IC

Q503 Q504 Q505 Q506 QL201

QR201 R201 R202 R203.204 R205

R207.208 R211-213 R214-218 R222 R223

R224 R225 R226 R231.232 R233

R236 R238 R239 R240 R241

KTC3198Y DTC114Y DTA114Y KTC3198Y KTD1303

KTD1303

4.7K 82R 100K 1K

100K 220R 1K 220R 560R

10K

5.6K 330R 220R 1K

330R 27K 330R 150R 470R

TRANSISTOR TRANSISTOR TRANSISTOR TRANSISTOR TRANSISTOR

TRANSISTOR RESISTOR 5% RESISTOR 5% RESISTOR 5% RESISTOR 5%

RESISTOR 5% RESISTOR 5% RESISTOR 5% RESISTOR 5% RESISTOR 5%

IC204 IC205 IC301 IC401 IC501

✰

ICM101 J321 JACK1 JACK2

L201-206 L207 L500 LFL200 LFR200

Q201.202 Q204 Q206.207 Q209 Q211

Q212 Q213-216 Q219 Q222 Q223

LA3450 NJM072DE LA1245 LA2230 NJM317F

HEAT SINK(24X17X30) LTV817

4.7K MINI JACK RCA 2P

56UH

20.8MH 56UH KLM5B2-T KLM5B2-T

KTC3198Y DTA114Y DTA114Y 2SC1740S 2SC1740S

2SK192GR KTC3195Y KTC3198Y DTC114Y 2SK117

MPX IC DUAL OP AMP AM IF IC RDS IC REGULATOR IC

REG.IC HEAT SINKER PHOTO COUPLER IC RESISTOR 5% MULTI-ROOM JACK RCA JACK

INDUCTOR FTZ COIL INDUCTOR MPX LPF COIL MPX LPF COIL

TRANSISTOR TRANSISTOR TRANSISTOR TRANSISTOR TRANSISTOR

FET TRANSISTOR TRANSISTOR TRANSISTOR FET

R242 R243 R244 R245 R246

R247 R248 R249 R250 R257.258

R259 R260 R261 R262 R263

R264 R265.266 R271 R272.273 R274

R275 R276 R277 R278 R279

330R 15K 390R

6.8K

3.3K

22R 390R 330R

4.7K 330R

6.8K

3.3K 39R 390R 330R

4.7K 330R 330R 100K 18K

47K 1K 10R(1W) 10K

3.3K

RESISTOR 5% RESISTOR 5% RESISTOR 5% RESISTOR 5% RESISTOR 5%

RESISTOR 5% RESISTOR 5% WATT RESISTOR RESISTOR 5% RESISTOR 5%

Q225 Q301 Q302 Q501 Q502

DTA114Y 2SK192GR DTA114Y DTC114Y BKTA1267Y

TRANSISTOR FET TRANSISTOR TRANSISTOR TRANSISTOR

R281 R282 R283 R284.285 R286

3

18K 1K 10K 120K

3.3K

RESISTOR 5% RESISTOR 5% RESISTOR 5% RESISTOR 5% RESISTOR 5%

Parts List-3

SYMBOL PARTS NO. DESCRIPTION SYMBOL PARTS NO. DESCRIPTION

R288 R289 R291.292 R297 R298

R299 R300 R301.302 R303 R304

R305 R306.307 R308 R309 R311

R312 R313 R314 R316.317 R318

R319 R320 R321 R401.402 R403

5.6K 10K 100K

4.7K 22R

1M

1.5K 100K 100R 820R

470R 220R 10K 100K 100R

1K

4.7K 2K 220R 82R

10K 100K 10K 560R 680R

RESISTOR 5% RESISTOR 5% RESISTOR 5% RESISTOR 5% RESISTOR 5%

RL203 RL204 RL205 RL206 RL294

RL295 RM101 RR201 RR202 RR203

RR204 RR205 RR206 RR294 RR295

RLY201.202 TC301 TC302 TL201 TL202

TL301 TL302 TL303 TL304 VR201

8.2K 470R 100K

3.3K 180K

100K 270R

3.3K

6.8K

8.2K

470R 100K

3.3K 180K 100K

G5A-237P DC12V TRIMER 10P(WHITE) TRIMER 20P(RED) FM-DET-A FM-DET-B

AM-OSC1 AM-ANT2 AM-IFT1 AM-IFT2 VR.47K

RESISTOR 5% RESISTOR 5% RESISTOR 5% RESISTOR 5% RESISTOR 5%

RELAY VARIABLE CAPACITOR VARIABLE CAPACITOR FM DET.COIL FM DET.COIL

AM OSC.COIL AM ANT .COIL AM IFT COIL AM IFT COIL VARIABLE RESISTOR

R404 R405 R406 R407 R408

R409 R410 R411 R412 R413

R501 R502 R503 R504 R505

R506 R507 R508 R509 R511

R513 R514 R515 R516 R517

1K 3M 1K

5.6K

3.3K

10K 3M 33K 10K 22K

4.7K 10K 82R 270R 200R

1.8K 330R(1W) 10K 270R(1W) 1K

22K 10K 100R 12K 10K

RESISTOR 5% RESISTOR 5% RESISTOR 5% RESISTOR 5% RESISTOR 5%

RESISTOR 5% WATT RESISTOR RESISTOR 5% WATT RESISTOR RESISTOR 5%

RESISTOR 5% RESISTOR 5% RESISTOR 5% RESISTOR 5% RESISTOR 5%

VR203 VR204 VR205 VR206 VR301

VR401 XTL201 XTL401

C101-107 C110.111 C112 C113 C114.115

C116 C117 C118 C119 C121

D101-107 D118 ENC101 FL101 Q101

VR.22K VR.1M VR.470K VR.4.7K VR.22K

VR.10K XTAL 7.2MHZ CSB456F15

X-1273-02 PCB ASSEMBLY

100PF

0.047UF 22UF/16V(SE TYPE)

0.1UF 820PF

0.1UF 820PF 1000PF 100PF

0.1UF

1N4148 1N4148 EC16B24202 SVR-12MM18(35S/12G) KTC3198Y

VARIABLE RESISTOR VARIABLE RESISTOR VARIABLE RESISTOR VARIABLE RESISTOR VARIABLE RESISTOR

VARIABLE RESISTOR CRYSTAL CERAMIC RESONATOR

CERAMIC CAPACITOR CERAMIC CAPACITOR ELECTRIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR

CERAMIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR CERAMIC CAPACITOR

SWITCHING DIODE SWITCHING DIODE VR ENCODER VFD FOR RDS/RBDS TRANSISTOR

R518 R519 R520 RL201 RL202

4.7K 56K 47K

3.3K

6.8K

RESISTOR 5% RESISTOR 5% RESISTOR 5% RESISTOR 5% RESISTOR 5%

R101-135 R136 R137-143 R146-149 R150.151

4

120K 10K 1K2 47K 2R2

RESISTOR 5% RESISTOR 5% RESISTOR 5% RESISTOR 5% RESISTOR 5%

Parts List-4

SYMBOL PARTS NO. DESCRIPTION SYMBOL PARTS NO. DESCRIPTION

X-1273-06 PCB ASSEMBLY

R152 R155.156 R157 R158-163 R164

SW101-112 SW114-116 SW118-120 SW122-124 SW126-128

10K 10K 47K 10K 1K2

TACT SWITCH(SKHVBH) TACT SWITCH(SKHVBH) TACT SWITCH(SKHVBH) TACT SWITCH(SKHVBH) TACT SWITCH(SKHVBH)

RESISTOR 5% RESISTOR 5% RESISTOR 5% RESISTOR 5% RESISTOR 5%

TACT SWITCH TACT SWITCH TACT SWITCH TACT SWITCH TACT SWITCH

C601-605 D601-604 IC601 JACK3

1UF/50V ZENER 12V MAX232CPE DB9 JACK(MALE)

OTHERS

011 FP-504 012 SK4-06A00 012 4TQF-15 014 C-4550A02 014 4TQN-12B#5

ELECTRIC CAPACITOR ZENER DIODE RS232 DRIVER IC DB9 JACK

FRONT PANEL ASSY KNOB 33F POWER BUTTON 14X14 UPPER COVER BOTTOM BOARD

U101 U102 XT101

CM101 QM101 RM102 RM103 RM104

RMC201

C540 SW201

TF201

CXP82832-182Q AT24C16 CST10.00MTW

X-1273-03 PCB ASSEMBLY

10UF/16V(SE TYPE) KTC3198Y 100R 150R

4.7K

CRV1M352-00B

X-1273-04 PCB ASSEMBLY

0.0047UF/400V POWER SW.TV-5

X-1273-05 PCB ASSEMBLY

022 T-1065N01

CPU EEP ROM RESONATOR 10.0MHZ

ELECTRIC CAPACITOR TRANSISTOR RESISTOR 5% RESISTOR 5% RESISTOR 5%

REMOTE CONTROL SENSOR

SPARK KILLER(AC CERAMIC) SWITCH

POWER TRANSFORMER

015 RP-360 019 4TSH-19#2 021 RLA145A00 034 SEL1124R 069 C-4629A01

072 4TR-2489 072 4TR-2875 072 4TR-3228 072 C-4620A01 072 C-4622A01

072 C-4623A01 072 C-4624A01 081 SK4-10A00 081 TZ-164-1 092 RR-T91

PRINTED REAR CHASSIS PLASTIC FOOT 50F AM LOOP ANTENNA LED AC INLET

3.5MM PLUG SHIELD CORD RCA PIN CORD T TYPE ANTENNA AC CORD SET for STD AC CORD SET for AUSTRALIA

AC CORD SET for UK AC CORD SET for CEE INSIDE CARTON STYROL SIDE MOULDING REMOTE UNIT

5

Adjustment

■ FM

* Necessary measurement equipment

RDS/STEREO Multiplexer 1 unit FM/AM Signal Generator 1 unit Audio Signal Analyzer 1 unit Oscilloscope 1 unit Digital Volt Meter (DVM) 1 unit

(A) Center adjust

❏ RDS/STEREO Multiplexer Setting

– MODE : MONO – Audio Frequency : 1KHz

❏ FM Signal Generator Setting

– Deviation : 75KHz – Radio Frequency : 98.0MHz – Output Level : 66dB

❏ RT955 Setting

– FM Frequency : 98.0MHz – Antenna Selection : A – FM MODE : MONO – IF MODE : WIDE

Oscilloscope

Monitor

Audio Signal Analyzer

L-CH

(or R-CH)

FM Signal Generator

BACK

(FM-DET -B) TL 202

TL 201 (FM-DET -A)

Jack 2 Ant-B

(ANT 201)

IC 203

R 282

Ant-A

(ANT 200)

DVM

(+)

(-)

FRONT

q Turn FM Signal Generator Modulation on w Connect DVM (+)(-) terminals to both ends of resistor R282 and measure the volt. e Make this measured volt '0' by adjusting TL201(FM-DET-A Coil).

(The adjustment should be within ±2mV) r After this adjustment, measure THD(Total Harmonic Distortion) with Audio Signal Generator. t Adjust THD to minimum point with TL202(FM-DET-B Coil). (THD should be within 0.5%)

Stereo Multiplexer

6

(B) Channel Separation adjust

❏ RDS/STEREO Multiplexer Setting

– MODE : STEREO (ONLY L-CH Signal OUT) – Audio Frequency : 1KHz

❏ FM Signal Generator Setting

– Deviation : 75KHz – Radio Frequency : 98.0MHz – Output Level : 66dB

❏ RT955 Setting

– FM Frequency : 98.0MHz – Antenna Selection : A – FM MODE : STEREO – IF MODE : WIDE

Oscilloscope

Monitor

Audio Signal Analyzer

L-CH (or R-CH OPEN)

Signal Generator

Stereo Multiplexer

BACK

Ant-A

(ANT 200)

VR 204

(Wide)

Jack 2 Ant-B

(ANT 201)

VR 205

(Narrow)

IC 204

FRONT

q Turn FM Signal Generator Modulation on after modulating only L-CH at STEREO Multiplexer.

w Confirm if 'STEREO' indicator is turned 'ON' on the display in the WIDE MODE. e Measure output level via Audio Signal Analyzer and make the level as standard. r Turn FM Signal Generator Modulation on after modulating only R-CH

at STEREO Multiplexer.

t Measure output level via Audio Signal Analyzer (measure per a dB) y Adjust output level to minimum position with VR204 (WIDE MODE CH-SEPA. ADJ.).

(lower than -40dB)

u Change RT955 IF MODE to NARROW. i Repeat the above q~t o Adjust output level to minimum point with VR205(NARROW MODE CH-SEPA. ADJ).

(lower than -38dB)

7

(C) TUNED Level adjust

❏ RDS/STEREO Multiplexer Setting

– MODE : STEREO – Audio Frequency : 1KHz

❏ FM Signal Generator Setting

– Deviation : 75KHz – Radio Frequency : 98.0MHz – Output Level : 26dB

❏ RT955 Setting

– FM Frequency : 98.0MHz – Antenna Selection : A – FM MODE : STEREO – IF MODE : WIDE

Oscilloscope

Monitor

Audio Signal Analyzer

L-CH

(or R-CH)

Signal Generator

Stereo Multiplexer

BACK

Jack 2 Ant-B

VR 206

(FM-ADJ 2)

IC 203

IC 202

S-METER

VR 201

(FM-ADJ 1)

(ANT 201)

J 615

CP 201

Ant-A

(ANT 200)

DVM

(+)

GND

(or Chassis)

(-)

FRONT

q Turn FM Signal Generator Modulation 'ON' (confirm if output level is 26dB) w measure volt while connecting DVM (-) terminal to GND (or Chassis) & connecting

(+) terminal to Jumper J615(S-METER).

e Adjust volt to 1.2V with VR201 (FM-ADJ1). r Adjust VR206(FM-ADJ2) up to the moment where 'STEREO' & 'TUNED' indicator

turns OFF & ON again. t Confirm if 'STEREO' & 'TUNED' turn OFF when decreasing the output level slowly from 26dB to 25dB, 24dB~~~. (Repeat the above e~r if not OFF in lower than 24dB.) y Set RT955's Search by MODE to AUTO at Signal Generator Output Level 26dB and start Auto search Tuning Encoder. Confirm if search stops at FM Frequency 98.0MHz. (Examine both of High Freq. ➝98.0MHz search, Low Freq. ➝98.0MHz search)

8

(D) RDS Level adjust

Turn VR 401 completely Clockwise o T

❏ RDS/STEREO Multiplexer Setting

– MODE : STEREO – Audio Frequency : 1KHz – RDS MODE : ON

❏ FM Signal Generator Setting

– Deviation : 75KHz – Radio Frequency : 98.0MHz – Output Level : 35dB

❏ RT955 Setting

– FM Frequency : 98.0MHz – Antenna Selection : A – FM MODE : STEREO – IF MODE : WIDE

Oscilloscope

Monitor

Audio Signal Analyzer

L-CH

(or R-CH)

Signal Generator

RDS/Stereo Multiplexer

(-)

GND

(or Chassis)

(+)

Jack 2 Ant-B

r Counterclockwise to Disable he RDS Function.

VR 401

(RDS-ADJ)

IC 401

BACK

C (406)

(RSD-ADJ)

(ANT 201)

Ant-A

(ANT 200)

FRONT

q Make sure that RDS/STEREO Multiplexer RDS Modulation is ON and turn FM Signal Generator Modulation ON w Connect oscilloscope terminal to low measuring point of C406(RDS ADJ) and measure. Make sure that the following waveform is output.

e Adjust waveform to maximum level with VR401(RDS ADJ). r Confirm if 'RDS' indicator is ON.

9

■ AM

* Necessary measurement equipment

AM Signal Generator 1 unit

Audio Signal Analyzer 1 unit DUMMY 1 unit Oscilloscope 1 unit

Digital Volt Meter (DVM) 1 unit

(A) VT adjust

❏ AM Signal Generator Setting

DUMMY

Signal Generator

BACK

Jack 2 Ant-B

(ANT 201)

TL 301

(AM-OSC)

TC 301 (White)

FFE

FFE 200

Ant-A

(ANT 200)

J 288

VT

DVM

(+)

(-)

GND

(or Chassis)

FRONT

q Adjust AM Frequency of RT-955 to 522KHz. w Connect (-) terminal of DVM with GND (or chassis) and connect (+) terminal

with Jumper J288 (VT CHECK ) and measure voltage. (Low Freq. VT)

e Adjust VT to 1.1V with TL301 (AM-OSC Coil). r Adjust AM Frequency of RT-955 to 1611KHz. t Measure VT and adjust VT to 7.5V with TC301 (WHITE Trimmer).

(High Freq. VT) y Repeat above w ~t steps 2 or 3 times until VT becomes 1.1V at AM Freq. 522KHz, and VT becomes 7.5V at 1611KHz.

*In case of USA version, AM freq. Range is 520KHz ~ 1710KHz, adjust as below. at 520KHz, VT = 1.1V (Low Freq. VT) at 1710KHZ VT = 8.5V(High Freq. VT)

10

(B) Output Level adjust

❏ AM Signal Generator Setting

– Modulation : 30% – Audio Frequency : 400Hz – Radio Frequency : 603KHz / 1404KHz / 999KHz – Output Level : 84dB

❏ RT955 Setting

– AM Frequency : 603KHz

Oscilloscope

Monitor

Audio Signal Analyzer

L-CH

(or R-CH)

DUMMY

Signal Generator

BACK

TL 302

(AM-ANT)

Jack 2 Ant-B

TL 303

(AM-IFT1)

TC 302

(Red)

IC 301

TL 304

(AM-IFT2)

(ANT 201)

Ant-A

(ANT 200)

FRONT

q Turn AM Signal Generator Modulation ON w Adjust RT955 AM Freq. to 603KHz and measure output level with Audio Signal analyzer. e Adjust output level to maximum point with TL302 (AM-ANT ). r Adjust AM Signal Generator & RT955 AM Freq. to 1404KHz and measure output level. t Adjust output level to maximum point with TC302 (RED Trimmer). y Repeat above w ~ e steps 2~3 times until adjusting to best output level. u Adjust AM Signal Generator & RT955 AM Freq. to 999KHz and measure output level. i Adjust level to maximum position with TL303 (AM-IFT1). o Adjust output level of AM Signal Generator to 100dB and measure THD. !0 Adjust THD to minimum position with TL304 (AM-IFT2).

(Lower than 1.2%)

*In case of USA version, AM Freq. step is 10KHz. So, change the standard freq. as below. 522KHz ➝ 520KHz, 1404KHz ➝ 1400KHz, 999KHz ➝ 1000KHz,

11

(C) TUNED Level adjust

– Audio Frequency : 1KHz

❏ AM Signal Generator Setting

– Modulation : 30% – Audio Frequency : 400Hz – Radio Frequency : 999KHz – Output Level : 84dB

❏ RT955 Setting

– AM Frequency : 999KHz

Oscilloscope

Monitor

Audio Signal Analyzer

L-CH

(or R-CH)

DUMMY

FM/AM Signal Generator

BACK

Jack 2 Ant-B

(ANT 201)

IC 301

VR 301

(AM-ADJ)

FFE

FFE 200

Ant-A

(ANT 200)

J 288

DVM

(+)

(-)

GND

(or Chassis)

FRONT

q Turn AM Signal Generator Modulation ON (Make sure if Output level is 84dB) w Adjust VR301 (AM-ADJ) up to the moment where 'TUNED' indicator turns

turns OFF & ON again. e Confirm if 'TUNED' turns OFF when decreasing the output level of AM signal Generator slowly from 84dB to 80dB. r Set RT955's Search MODE to AUTO at AM Signal Generator Output Level 84dB and start Auto search by Tunning Encoder. Confirm if search stops at AM Frequency 999KHz. (Check with both of High Freq. ➝ 999KHz search, Low Freq. ➝ 999KHz search)

*In case of USA version, AM Freq. Step is 10KHz. So, check above steps with 1000KHz instead of 999KHz.

12