Kenwood RXDM-37 Service manual

COMPACT Hi-Fi COMPONENT SYSTEM

70%70%

RXD-M37-L/M37-S

SERVICE MANUAL

(HM-337)

CD cover assy (F07-2028-08)

Power knob (K29-8426-08)

EQ/BASS knob (K29-8427-08)

Knob (K29-8431-08)

Display/Rec knob (K29-8428-08)

Search knob (K29-8430-08)

Cass. Lid assy (A53-2451-08)

In compliance with Federal Regulations, following are reproduction of labels on, or inside the product relating to laser product safety.

Caution : No connection of ground line if disassemble

the unit. Please connect the ground line on

rear panel, PCBs, Chassis and some others.

Volume knob (K29-8429-08)

Front cab. assy * (A60-)

* Refer to parts list on page 18.

KENWOOD Corp. certifies this equipment conforms to DHHS Regulations No.21 CFR 1040. 10, Chapter 1, subchapter J.

DANGER : Laser radiation when open and interlock defeated. AVOID DIRECT EXPOSURE TO BEAM.

CAUTION

Be sure to adhere to the following, or proper ventilation will be blocked causing damage or fire hazard.

Do not place any objects impairing heat radiation onto the top of the unit. Leave some space around the unit (from the largest outside dimension including projection) equal to or greater than, shown below.

Back panel : 10 cm

Top panel : 50 cm

Channel space switching

(except for the Europe and Australia)

The space between radio channels has been set to the one that prevails in the area to which the system is shipped. However, if the curren channel space setting does not match the setting in the area where the system is to be used, for instance when you move from area 1 or area 2 shown in the following table or vice versa, proper reception of AM/FM broadcasts cannot be expected. In this case, change the channel space setting for each AM and FM broadcast in accordance with your area by referring to the following table.

When the system is on, press TUNER/band button to select TUNER mode and waveband of which you wish to set the channel space. Then, while pressing 6 button, press 4 button to switch the channel space.

Area

U.S.A., Canada and South American countries

CHANNEL

Space frequency

Other countries

FM: 100 kHz AM: 10 kHz

FM: 50 kHz AM: 9 kHz

CAUTION

Place the unit where the AC power cord can be easily unplugged. The power in this unit will not be completely cut off from the AC wall outlet when the power completely, unplug the AC power cord from the AC wall outlet.

The marking of products using lasers

The marking this product has been classified as Class 1. It means that there is no danger of hazardous radiation outside the product.

Location: Bottom

CLASS 1 LASER PRODUCT LASER KLASSE 1 APPAREIL A LASER DE CLASSE 1 LUOKAN 1 LASERLAITE KLASS 1 LASERAPPARAT

Resetting the Microcomputer

The microcomputer may malfunction (unit cannot be operated, or shows an erroneous display) if the power cord is unplugged while the power is ON, or due to some other external factor. If this happens, execute the following procedure to reset the microcomputer and return the unit to its normal operating condition.

Plug in the AC power cord to the wall outlet, and within 5 seconds, press and hold down the 7 button and press CD button.

• Please note that resetting the microcomputer

will clear the contents of the memory and return the unit to the state it was in when it left the factory.

Remote control unit (1) (A70-1690-08): E (A70-1691-08): MX

AM loop antenna (1) (T90-0908-08)

ANT TERMI CVR (F07-2029-08)

Batteries (R6/AA) (2)

AC plug adapter (1) (E03-0115-05)

Use to adapt the plug on the power cord to the shape of the wall outlet. (Accessory only for regions where

use is necessary.)

(–)

RXD-M37

CONTENTS / ACCESSORIES / CAUTIONS

CONTENTS / ACCESSORIES / CAUTIONS...............2

EXTERNAL VIEW ........................................................3

ADJUSTMENT .............................................................4

PC BOARD ..................................................................8

ACCESSORIES

CAUTIONS

SCHEMATIC DIAGRAM ............................................12

EXPLODED VIEW .....................................................17

PARTS LIST...............................................................18

SPECIFICATIONS..................................BACK COVER

Rear cab. (A80-4503-08)

Voltage selector * (S62-0124-08)

RXD-M37

EXTERNAL VIEW

* Refer to parts list on page 18.

System configuration

SYSTEM RECEIVER SPEAKERS

HM-337-L RXD-M37-L LS-M37-L HM-337-S RXD-M37-S LS-M37-S

Rubber foot (G11-2957-08)

RXD-M37

SERVICE ADJUSTMENT

Lubrication

The mechanical parts are factory coated with a thin coat of light grease and should not require further lubrication. If a light grease is applied, be careful not to get any grease on the play/record head or erase head, hubs, pulleys, tapes reels, drive belts, or switches. Use a good lubricant such as Silicon Lube G322L or Lubricate.

Service Check

Before aligning the mechanism, wipe off any accumulated dirt with denatured alcohol. Wipe around parts where the tape contacts and around all rotating parts. Drive belts are specially processed. Do not clean them with alcohol.

Mechanical Torque

Use a cassette type torque gauge and check the tape mechanism. Take-up torque 35 to 70 g-cm Rewind torque 50 g-cm min. Fast forward torque 50 g-cm min.

Pinch Wheel Pressure

No adjustment to the pinch roller spring is necessary. It should be sufficient to give at least 40 g-cm pull force.

Tape Head Servicing

Each time the unit is serviced, the face of all heads should be thoroughly cleaned with denatured alcohol or commercial head cleaning solution. The playback head should be demagnetized with a commercial demagnetizer. Accumulation of tape oxide during normal operations can cause problems, including loss of high frequencies and wow and flutter.

Erase Head

The erase head is properly aligned when the tape rides directly between the tape guide on the head without crinkling the tape.

Play/Record and Playback Head Azimuth Adjustment

To adjust the play/record and playback head azimuth screw:

1. Connect two (2) VTVMs and a dual trace scope to the stereo headphone jack (as shown) with a 32 ohm dummy load. (See Figure 1.)

VTVM VTVM

DUMMY LOAD

JK801

SCOPE

CH1

CH2

Figure 1. Azimuth Adjustment

ADJUSTMENT

2. Insert a 10 kHz test tape (Teac MTT-1141V or Equivalent) into the tape mechanism and play it back.

3. While playing back the test tape, slowly turn the azimuth adjusting screw until the amplitude of both channel output waveforms is maximum and in phase. (See Figure 2.)

4. Secure the azimuth screw in place with glue or paint after making the adjustment.

Figure 2. Head Output Signal

Tape Speed Adjustment

1. Set the function switch to TAPE.

2. Connect a frequency counter with a 32 ohm dummy load to the stereo headphone jack. (See Figure 3.)

FREQUENCY COUNTER

DUMMY LOAD

JK801

Figure 3. Tape Speed Adjustment

3. Insert and play back a 3 kHz test tape (Teac MTT-111 or Equivalent) into the tape mechanism.

4. Insert an insulated alignment tool and adjust the tape speed potentiometer (MOTOR) until the frequency counter indicates 2940 Hz to 3090 Hz.

Bias Oscillator Frequency and Level Adjustment

1. Set the function switch to TAPE and the record and play tape mechanism to RECORD.

2. Connect a VTVM and frequency counter to test point R/P HEAD.

3. Adjust bias oscillator coil T360 until the frequency counter indicates 81 kHz ± 0.5 kHz.

4. Confirm the record head voltage equal to: 6-12V.

5. Confirm the erase head voltage equal to: 15-24V.

RXD-M37

TUNER ALIGNMENT PROCEDURE Equipment needed:

1. AM Signal generator

2. FM Signal generator

3. DC Voltage meter

4. Oscilloscope

5. Output meter (VTVM)

AM Alignment

Step S/G Frequency Dial Setting Indicator Adjust Remarks

1 450 kHz (1 kHz 30% mod.) 612 kHz Connect

oscilloscope or VTVM to speaker

jack

T201 Adjust until

maximum output

2 531 kHz (1 kHz 30% mod.) Low end Connect DC voltage

meter to test point Vt and ground

T202 Adjust until

Vt equal to

1.5 ± 0.05V

3 1602 kHz (1 kHz 30% mod.) High end Same as step 2 Confirm Vt:

6.5~8.5V

4 612 kHz (1 kHz 30% mod.) 612 kHz

Same as step 1 T203 Maximum output

5 1404 kHz (1 kHz 30% mod.) 1404 kHz Same as step 1 VC201 Maximum output 6 Repeat steps 4 and 5 to minimize tracking error 7 999 kHz

(1 kHz 30%mod.)

999 kHz

Same as step 1 Offset is less than

6 dB.

60 cm

AM SIGNAL GENERATOR

AM LOOP ANT

AM LOOP

ANTENNA

DUMMY LOAD

TEST UNIT

VTVM

R-OUT

L-OUT

GND

Figure 4. AM IF/RF Tracking

TEST UNIT

Figure 5. AM Band Frequency Coverage Alignment

GROUND

METER

Vt DC

ADJUSTMENT

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