AIWA NSX-SZ50 (01) PDF Document

The components for the AIWA NSX-SZ50 system are as follows:

The specifications for the AIWA NSX-SZ50 are as follows:

Main unit CX-NSZ50(LH)

<FM tuner section>

Tuning range: 87.5 MHz to 108 MHz

Usable sensitivity (IHF): 13.2 dBf

Antenna terminals: 75 ohms (unbalanced)

<AM (MW) tuner section>

Tuning range: 531 kHz to 1602 kHz (9 kHz step)

Usable sensitivity: 350 µV/m

Antenna: Loop antenna

<Amplifier section>

Mid-high frequency amplifier

Power output: Rated: 20 W + 20 W (8 ohms, T.H.D. 1%, 1 kHz), Reference: 25 W + 25 W (8 ohms, T.H.D. 10%, 1 kHz)

Total harmonic distortion: 0.1% (10W, 1 kHz, 8 ohms, DIN AUDIO)

Low frequency amplifier

Power output: Rated: 60 W + 60 W (6 ohms, T.H.D. 1%, 130 Hz), Reference: 75 W + 75 W (6 ohms, T.H.D. 10%, 130 Hz)

Total harmonic distortion: 0.1% (30W, 130 kHz, 6 ohms, DIN AUDIO)

Inputs: VIDEO/AUX: 500 mV, MIC: 1.0mV (10 K ohms)

Outputs: SPEAKERS HIGH FREQ: accept speakers of 8 ohms or more, SPEAKERS LOW FREQ: accept speakers of 6 ohms or more, PHONES (stereo jack): accepts headphones of 32 ohms or more

<Cassette deck section>

Track format: 4 tracks, 2 channels stereo

Frequency response: 50 Hz – 16000 Hz

Recording system: AC bias

Heads: Deck 1: Playback head x 1, Deck 2: Recording / Playback head x 1, erase head x 1

<Compact disc player section>

Laser: Semiconductor laser (λ = 780 nm)

D-A converter: 1 bit dual

Signal-to-noise ratio: 85 dB (1 kHz, 0 dB)

Harmonic distortion: 0.05% (1 kHz, 0 dB)

<General>

Power requirements: 120V/220-230V/240V AC switchable, 50/60 Hz

Power consumption: 130 W

Standby power consumption: 20 W (power-economizing mode set to OFF), 0.9 W (power-economizing mode set to ON)

Dimensions of main unit (W x H x D): 260 x 326 x 345 mm

Weight of main unit: 9.0 kg

Speaker system SX-WNSZ50(LH)

Speaker system: 3 way, bass reflex (magnetic shielded type)

Speaker units: Subwoofer: 160 mm cone type, Full range: 100 mm cone type, Super tweeter: 20 mm ceramic type

Impedance: 6 ohms/8 ohms

Sensitivity: 86 dB/W/m

Dimensions (W x H x D): 240 x 324 x 271 mm

Weight: 4.8 kg (10 lbs 9 oz.)

This set employs a laser. Be sure to follow these instructions carefully when servicing:

WARNING! WHEN SERVICING, DO NOT APPROACH THE LASER EXIT WITH THE EYE TOO CLOSELY. IN CASE IT IS NECESSARY TO CONFIRM LASER BEAM EMISSION, BE SURE TO OBSERVE FROM A DISTANCE OF MORE THAN 30cm FROM THE SURFACE OF THE OBJECTIVE LENS ON THE OPTICAL PICK-UP BLOCK.

CAUTION: Use of controls or adjustments or performance of procedures other than those specified herein may result in hazardous radiation exposure.

Caution: Invisible laser radiation when open and interlocks defeated avoid exposure to beam.

The AIWA NSX-SZ50 is classified as a CLASS 1 LASER product. The CLASS 1 LASER PRODUCT label is located on the rear exterior.

Body or clothes electrostatic potential could ruin the laser diode in the optical block. Be sure to ground your body and workbench, and use care that clothes do not touch the diode.

1. After making the connection, remove the protective solder from the designated point on the PICK-UP Assy P.C.B.

To prevent secondary trouble from charged capacitors (C101, 102), perform the following discharge procedure before starting repair work:

1. Remove the AC power cord.

2. Connect a discharging resistor to a lead wire with clips on both ends. Connect the other end of the lead wire to the metal chassis. The correct resistor depends on the charging voltage:

3. Contact the other end of the discharging resistor to the positive (+) side of C101 for two seconds.

4. Contact the same end of the discharging resistor to the negative (-) side of C102 for two seconds.

5. Check that the voltage across C101 and C102 has decreased to 1V or less using a multimeter or oscilloscope.

Note: The reference numbers of the electrolytic capacitors can change depending on the model. Be sure to check the schematic diagram before starting.

Before exchanging the microcomputer, check its HOLD terminal. When the main power cannot be turned on, it may be due to the HOLD terminal being at a “L” (low) level.

To judge if the microcomputer is good:

1. Turn on the AC main power.

2. Confirm if the main power is turned on and the HOLD terminal of the microcomputer keeps the “H” (high) level.

3. If the HOLD terminal is at an “L” level, it means the abnormality detection circuit is working correctly, and the microcomputer is judged to be good. In this case, check if the POWER AMPLIFIER circuit or power supply circuit has any abnormalities.

If the AIWA NSX-SZ50 does not work correctly because the microcomputer is not reset, perform the forced-reset procedure:

1. Remove the AC power cord.

2. Short both ends of the electrolytic capacitor C113 that is connected to the VDD pin of the microcomputer with tweezers.

3. Connect the AC power cord again. If the microcomputer returns to normal operation, the microcomputer is good.

Note: The reference number of the capacitor (C113) and pin number of the microcomputer can change depending on the model. Always check the schematic diagram first.

The chip resistor part codes can be identified using the following table:

To check the clock frequency:

Settings: Test point: TP2

Method: Set to AM 1710kHz and check that the test point is 2160kHz ± 45Hz.

To check the AM VT (Voltage Tuning):

Settings: Test point: TP1 (VT)

Method: Set to AM 1710kHz, 530kHz and check that the test point is less than 8.5V (1710kHz) and more than 0.6V (530kHz).

To check the FM VT (Voltage Tuning):

Settings: Test point: TP1 (VT)

Method: Set to FM 87.5MHz, 108.0MHz and check that the test point is more than 0.5V (87.5MHz) and less than 8.0V (108.0MHz).

To adjust AM tracking:

Settings: Test point: TP8(Lch), TP9(Rch)

Adjustment location: L951(1/3) for 1000kHz

Method: Set to AM 1000kHz and adjust L951(1/3) so that the level at the test point becomes maximum.

To check FM tracking:

Settings: Test point: TP8(Lch), TP9(Rch)

Method: Set to FM 98.0MHz and check that the test point is less than 9dBμV.

To adjust the AM Intermediate Frequency:

Settings: Test point: TP5(Lch), TP6(Rch)

Adjustment location: L802 for 1000 kHz

To adjust DC Balance and Mono Distortion:

Settings:

Test point: TP3, TP4 (DC Balance); TP8(Lch), TP9(Rch) (Distortion)

Adjustment location: L801

Input level: 60dBμV

Method: Set to FM 98.0MHz and adjust L801 so that the voltage between TP3 and TP4 becomes 0V ± 0.04V. Next, check that the distortion is less than 1.3%.

This adjustment is for DECK 2.

Settings:

Test tape: TTA-100

Test point: TP8(Lch), TP9(Rch)

Adjustment location: SFR1

Method: Play back the test tape and adjust SFR1 so that the frequency counter reads 3000Hz ± 5Hz and ±45Hz (REV) with respect to forward speed.

This adjustment is for DECK 1 and DECK 2.

Settings:

Test tape: TTA-330

Test point: TP8(Lch), TP9(Rch)

Adjustment location: Head azimuth adjustment screw

Method: Play back (FWD) the 8kHz signal of the test tape and adjust the screw so that the output becomes maximum. Next, perform on REV PLAY mode.

This check is for DECK 1 and DECK 2.

Settings:

Test tape: TTA-300

Test point: TP8(Lch), TP9(Rch)

Method: Play back the 315Hz and 8kHz signals of the test tape and check that the output ratio of the 8kHz signal with respect to that of the 315Hz signal is within 5dB.

To adjust the micro-controller oscillator:

Settings:

Test point: TP7 and GND

Adjustment location: L331

Method: Insert the AC plug while pressing the POWER and TUNER function keys. Adjust L331 so that the frequency at the test point is 153.84Hz ± 0.15Hz.

Insert a flat-bladed screwdriver into the position indicated by the arrows and remove the panel. Remove the screws of each speaker unit and then remove the speaker units.

Remove the grill frame and four pieces of rubber caps by pulling out with a flat-bladed screwdriver. Remove the screws from the holes where the rubber caps were installed. Insert a flat-bladed screwdriver into the position indicated by the arrows and remove the panel. Remove the screws of each speaker unit and then remove the speaker units.

Insert a flat-bladed screwdriver into the position indicated by the arrows and remove the panel. To remove the speaker unit, turn it counter-clockwise while inserting a flat-bladed screwdriver into one of the hollows around it. After replacing the speaker unit, install it by turning it clockwise until a “click” sound comes out.

How to Remove the PANEL, FR

1. Insert the flat head screwdriver tip into the gap between the PANEL, FR and the PANEL, SPKR. Tap the head of the screwdriver with a plastic hammer to create a clearance.

2. Insert the cut chisel into the clearance and tap the head of the chisel with a plastic hammer to remove the PANEL, FR.

3. Place the speaker horizontally. Tap the head of the cut chisel with a plastic hammer to remove the PANEL, FR completely.

How to Attach the PANEL, FR

Attach the PANEL, FR to the PANEL, SPKR. Tap the four corners of the PANEL, FR with the plastic hammer to fit the PANEL, FR into the PANEL, SPKR completely.