NAD S-400 Service manual

SERVICE MANUAL

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S 400

RDS FM TUNER

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SERVICE MANUAL

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S 400

© 2003 NAD ELECTRONICS INTERNATIONAL

ONTARIO, CANADA

All rights reserved. No part this publication may be reproduced, stored or transmitted in any form without

the written permission of NAD Electronics International

RDS FM TUNER

S 400

RDS FM TUNER

CAUTION : DO NOT ATTEMPT TO MODIFY THIS PRODUCT IN ANY WAY,
NEVER PERFORM CUSTOMIZED INSTALLATIONS WITHOUT MANUFAC­TURER’S APPROVAL. UNAUTHORIZED MODIFICATIONS WILL NOT ONLY
VOID THE WARRANTY, BUT MAY LEAD TO YOUR BEING LIABLE FOR ANY
RESULTING PROPERTY DAMAGE OR USER INJURY.

SERVICE WORK SHOULD BE PERFORMED ONLY AFTER YOU ARE
THOROUGHLY FAMILIAR WITH ALL OF THE FOLLOWING SAFETY
CHECKS AND SERVICING GUIDELINES. TO DO OTHERWISE,
INCREASES THE RISK OF POTENTIAL HAZARDS AND INJURY TO THE
USER.

WHILE SERVICING, USE AN ISOLATION TRANSFORMER FOR PROTEC­TION FROM A.C. LINE SHOCK.

SAFETY CHECKS

AFTER THE ORIGINAL SERVICE PROBLEM HAS BEEN CORRECTED. A
CHECK SHOULD BE MADE OF THE FOLLOWING.

SUBJECT : FIRE & SHOCK HAZARD

1. BE SURE THAT ALL COMPONENTS ARE POSITIONED IN SUCH A WAY
AS TO AVOID POSSIBILITY OF ADJACENT COMPONENT SHORTS.
THIS IS ESPECIALLY IMPORTANT ON THOSE MODULES WHICH ARE
TRANSPORTED TO AND FROM THE REPAIR SHOP.

2. NEVER RELEASE A REPAIR UNLESS ALL PROTECTIVE DEVICES
SUCH AS INSULATORS, BARRIERS, COVERS, SHIELDS, STRAIN
RELIEFS, POWER SUPPLY CORDS, AND OTHER HARDWARE HAVE
BEEN REINSTALLED PER ORIGINAL DESIGN. BE SURE THAT THE
SAFETY PURPOSE OF THE POLARIZED LINE PLUG HAS NOT BEEN
DEFEATED.

3. SOLDERING MUST BE INSPECTED TO DISCOVER POSSIBLE COLD
SOLDER JOINTS, SOLDER SPLASHES OR SHARP SOLDER POINTS.
BE CERTAIN TO REMOVE ALL LOOSE FOREIGN PARTICLES.

4. CHECK FOR PHYSICAL EVIDENCE OF DAMAGE OR DETERIORATION
TO PARTS AND COMPONENTS, FOR FRAYED LEADS, DAMAGED
INSULATION (INCLUDING A.C. CORD), AND REPLACE IF NECESSARY.
FOLLOW ORIGINAL LAYOUT, LEAD LENGTH AND DRESS.

5. NO LEAD OR COMPONENT SHOULD TOUCH A RECIVING TUBE OR
A RESISTOR RATED AT 1 WATT OR MORE. LEAD TENSION AROUND
PROTRUDING METAL SURFACES MUST BE AVOIDED.

6. ALL CRITICAL COMPONENTS SUCH AS FUSES, FLAMEPROOF
RESISTORS, CAPACITORS, ETC. MUST BE REPLACED WITH EXACT
FACTORY TYPES, DO NOT USE REPLACEMENT COMPONENTS
OTHER THAN THOSE SPECIFIED OR MAKE UNRECOMMENDED CIR­CUIT MODIFICATIONS.

7. AFTER RE-ASSEMBLY OF THE SET ALWAYS PERFORM AN A.C.
LEAKAGE TEST ON ALL EXPOSED METALLIC PARTS OF THE CABI­NET, (THE CHANNEL SELECTOR KNOB, ANTENNA TERMINALS. HAN­DLE AND SCREWS) TO BE SURE THE SET IS SAFE TO OPERATE
WITHOUT DANGER OF ELECTRICAL SHOCK. DO NOT USE A LINE
ISOLATION TRANSFORMER DURING THIS TEST USE AN A.C. VOLT­METER, HAVING 5000 OHMS PER VOLT OR MORE SENSITIVITY, IN
THE FOLLOWING MANNER; CONNECT A 1500 OHM 10 WATT RESIS­TOR, PARALLELED BY A .15 MFD. 150.V A.C TYPE CAPACITOR
BETWEEN A KNOWN GOOD EARTH GROUND (WATER PIPE, CON­DUIT, ETC.) AND THE EXPOSED METALLIC PARTS, ONE AT A TIME.
MEASURE THE A.C. VOLTAGE ACROSS THE COMBINATION OF 1500
OHM RESISTOR AND .15 MFD CAPACITOR. REVERSE THE A.C. PLUG
AND REPEAT A.C. VOLTAGE MEASUREMENTS FOR EACH EXPOSED
METALLIC PART. VOLTAGE MEASURED MUST NOT EXCEED 75
VOLTS R.M.S. THIS CORRESPONDS TO 0.5 MILLIAMP A.C ANY
VALUE EXCEEDING THIS LIMIT CONSTITUTES A POTENTIAL SHOCK
HAZARD AND MUST BE CORRECTED IMMEDIATELY.

SUBJECT: GRAPHIC SYMBOLS

THE LIGHTNING FLASH WITH APROWHEAD SYMBOL. WITHIN
AN EQUILATERAL TRIANGLE, IS INTENDED TO ALERT THE
SERVICE PERSONNEL TO THE PRESENCE OF UNINSULATED
“DANGEROUS VOLTAGE” THAT MAY BE OF SUFFICIENT MAG­NITUDE TO CONSTITUTE A RISK OF ELECTRIC SHOCK.

THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIAN­GLE IS INTENDED TO ALERT THE SERVICE PERSONNEL TO
THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN
SERVICE LITERATURE.

SUBJECT : X-RADIATION

1. BE SURE PROCEDURES AND INSTRUCTIONS TO ALL SERVICE PER­SONNEL COVER THE SUBJECT OF X-RADIATION. THE ONLY POTEN­TIAL SOURCE OF X-RAYS IN CURRENT T.V. RECEIVERS IS THE PIC­TURE TUBE. HOWEVER, THIS TUBE DOES NOT EMIT X-RAYS WHEN
THE HIGH VOLTAGE IS AT THE FACTORY SPECIFIED LEVEL. THE
PROPER VALUE IS GIVEN IN THE APPLICABLE SCHEMATIC. OPERA­TION AT HIGHER VOLTAGES MAY CAUSE A FAILURE OF THE PIC­TURE TUBE OR HIGH VOLTAGE SUPPLY AND, UNDER CERTAIN CIR­CUMSTANCES, MAY PRODUCE RADIATION IN EXCESS OF DESIR­ABLE LEVELS.

2. ONLY FACTORY SPECIFIED C.R.T. ANODE CONNECTORS MUST BE
USED. DEGAUSSING SHIELDS ALSO SERVE AS AN X-RAY SHIELD IN
COLOR SETS, ALWAYS RE-INSTALL THEM.

3. IT IS ESSNTIAL THAT SERVICE PERSONNEL HAVE AVAILABLE AN
ACCURATE AND RELIABLE HIGH VOLTAGE METER. THE CALIBRA­TION OF THE METER SHOULD BE CHECKED PERIODICALLY
AGAINST A REFERENCE STANDARD, SUCH AS THE ONE AVAILABLE
AT YOUR DISTRIBUTOR.

4. WHEN THE HIGH VOLTAGE CIRCUITRY IS OPERATING PROPERLY
THERE IS NO POSSIBILITY OF AN X-RADIATION PROBLEM. EVERY
TIME A COLOR CHASSIS IS SERVICED. THE BRIGHTNESS SHOULD
BE RUN UP AND DOWN WHILE MONITORING THE HIGH VOLTAGE
WITH A METER TO BE CERTAIN THAT THE HIGH VOLTAGE DOES
NOT EXCEED THE SPECIFIED VALUE AND THAT IT IS REGULATING
CORRECTLY. WE SUGGEST THAT YOU AND YOUR SERVICE ORGA­NIZATION REVIEW TEST PROCEDURES SO THAT VOLTAGE REGU­LATION IS ALWAYS CHECKED AS A STANDARD SERVICING PROCE­DURE AND THAT THE HIGH VOLTAGE READING BE RECORDED ON
EACH CUSTOMER’S INVOICE.

5. WHEN TROUBLESHOOTING AND MAKING TEST MEASUREMENTS IN
A PRODUCT WITH A PROBLEM OF EXCESSIVE HIGH VOLTAGE,
AVOID BEING UNNECESSARILY CLOSE TO THE PICTURE TUBE AND
THE HIGH VOLTAGE SUPPLY. DO NOT OPERATE THE PRODUCT
LONGER THAN IT IS NECESSARY TO LOCATE THE CAUSE OF EXCES­SIVE VOLTAGE.

6. REFER TO HV. B+ AND SHUTDOWN ADJUSTMENT PROCEDURES
DESCRIBED IN THE APPROPRIATE SCHEMATIC AND DIAGRAMS
(WHERE USED).

SUBJECT: IMPLOSION

1. ALL DIRECT VIEWED PICTURE TUBES ARE EQUIPPED WITH AN INTE­GRAL IMPLOSION PROTECTION SYSTEM, BUT CARE SHOULD BE
TAKEN TO AVOID DAMAGE DURING INSTALLATION, AVOID
SCRATCHING THE TUBE. IF SCRATCHED REPLACE IT.

2. USE ONLY RECOMMENDED FACTORY REPLACEMENT TUBES.

SUBJECT : TIPS ON PROPER INSTALLATION

1. NEVER INSTALL ANY PRODUCT IN A CLOSED-IN RECESS, CUBBY­HOLE OR CLOSELY FITTING SHELF SPACE, OVER OR CLOSE TO
HEAT DUCT, OR IN THE PATH OF HEATED AIR FLOW.

2. AVOID CONDITIONS OF HIGH HUMIDITY SUCH AS: OUTDOOR PATIO
INSTALLATIONS WHERE DEW IS A FACTOR, NEAR STEAM RADIA­TORS WHERE STEAM LEAKAGE IS A FACTOR, ETC.

3. AVOID PLACEMENT WHERE DRAPERIES MAY OBSTRUCT REAR
VENTING. THE CUSTOMER SHOULD ALSO AVOID THE USE OF DEC­ORATIVE SCARVES OR OTHER COVERINGS WHICH MIGHT
OBSTRUCT VENTILATION.

4. WALL AND SHELF MOUNTED INSTALLATIONS USING A COMMER­CIAL MOUNTING KIT, MUST FOLLOW THE FACTORY APPROVED
MOUNTING INSTRUCTIONS. A PRODUCT MOUNTED TO A SHELF OR
PLATFORM MUST RETAIN ITS ORIGINAL FEET (OR THE EQUIVALENT
THICKNESS IN SPACERS) TO PROVIDE ADEQUATE AIR FLOW
ACROSS THE BOTTOM. BOLTS OR SCREWS USED FOR FASTENERS
MUST NOT TOUCH ANY PARTS OR WIRING. PERFORM LEAKAGE
TEST ON CUSTOMIZED INSTALLATIONS.

5. CAUTION CUSTOMERS AGAINST THE MOUNTING OF A PRODUCT ON
SLOPING SHELF OR A TILTED POSITION, UNLESS THE PRODUCT IS
PROPERLY SECURED.

6. A PRODUCT ON A ROLL-ABOUT CART SHOULD BE STABLE ON ITS
MOUNTING TO THE CART. CAUTION THE CUSTOMER ON THE HAZ­ARDS OF TRYING TO ROLL A CART WITH SMALL CASTERS ACROSS
THRESHOLDS OR DEEP PILE CARPETS.

7. CAUTION CUSTOMERS AGAINST THE USE OF A CART OR STAND
WHICH HAS NOT BEEN LISTED BY UNDERWRITERS LABORATORIES,
INC. FOR USE WITH THEIR SPECIFIC MODEL OF TELEVISION
RECEIVER OR GENERICALLY APPROVED FOR USE WITH T.V.’S OF
THE SAME OR LARGER SCREEN SIZE.

8. CAUTION CUSTOMERS AGAINST THE USE OF EXTENSION CORDS.
EXPLAIN THAT A FOREST OF EXTENSIONS SPROUTING FROM A SIN­GLE OUTLET CAN LEAD TO DISASTROUS CONSEQUENCES TO
HOME AND FAMILY.

PRODUCT SAFETY SERVICING GUIDELINES FOR NAD PRODUCTS

A.C. VOLTMETER

GOOD EARTH GROUND
SUCH AS THE WATER
PIPE. CONDUIT. ETC

PLACE THIS PROBE
ON EACH EXPOSED
METAL PART

ALIGNMENT PROCEDURE FOR NAD S400:

EQUIPMENT REQUIRED FOR ALIGNMENT PROCEDURE:

•

FM RF signal generator capable of 75MHz to 109MHz output @ 75Ω that can separately modulate left and
right channels (Panasonic model # VP-7637A or equivalent)

•

DMM with a basic accuracy of better than +/- 0.05%.

•

High impedance (10 MΩ) dual channel audio AC voltmeter with decibel readout with accuracy of better than
+/- 3%.

•

Dual channel oscilloscope that has greater than 20MHz bandwidth.

•

Non-Ferris tuning tools.

ALIGNMENT PROCEDURE:

WARNING: MOST OF THE ALIGNMENT POINTS AND ADJUSTMENTS ARE FOUND UNDER A SEALED
BY SOLDER SHIELD. NORMALLY THERE SHOULD NOT BE A REASON FOR ACCESS TO THE
ALIGNMENT POINTS AND ADJUSTMENTS, UNLESS PARTS HAVE BEEN REPLACED. ONLY
ATTEMPT ALIGNMENT IF ALL EQUIPMENT MENTIONED ABOVE IS AVAILABLE AND ONLY IF
QUALIFIED PERSONNEL PERFORM THE ALIGNMENT.

Depending on the country, the S400 can be setup differently via the front panel buttons. Hold down the

MODE

button while switching on the power. You now see a start up menu, where you can toggle between

the various menu options with the

DISPLAY

button and save the choice with the

STORE

button.

For continental US select:

BAND

=

EU-USA

(87.500 MHz to 108.500 MHz)

EQ

=

75us

AUTO STEP

=

100kHz

,

DELETE PRESETS?

= (

DISPLAY

button = yes,

STORE

button = no)?

For Europe select:

BAND

=

EU-USA

(87.500 MHz to 108.500 MHz)

EQ

=

50us

AUTO STEP

=

50kHz

,

DELETE PRESETS?

= (

DISPLAY

button = yes,

STORE

button = no)?

For Japan select:

BAND

=

JAPAN

(75.500 MHz to 90.500 MHz)

EQ

=

75us

AUTO STEP

=

100kHz

,

DELETE PRESETS?

= (

DISPLAY

button = yes,

STORE

button = no)?

Alignment of RF front-end:

1) Press the IF-button to select

IF NARROW.

Press the

ANTENNA

-button and select

ANTENNA 2.

Then connect an RF signal generator to

ANTENNA

port #2 and set to:
Amplitude = 45 dBu
Pilot tone = off
Modulation = off
Frequency = 98.000 MHz.

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2) Tune the

S400

to 108.500 MHz (90.500 MHz for Japan). Looking at the

S400

from the front, measure

with a DMM at the right hand side of

R21

found at position “R6” on the board. Adjust

L13

until the

tuning voltage is 10.0V DC.

3) Tune the

S400

to 98,000 MHz (83.00 MHz for Japan). Measure with an oscilloscope, the IF-signal

10.7 MHz at the common point between

CF3

and

CF4

found at position “O4” (see Figure 1). This

point will be “DC voltage free”.

Leave the oscilloscope set to this point until told to remove it

.

In the order listed below:

•

Adjust

L10

until the IF-signal for maximum setting.

•

Adjust L7 until the IF-signal for maximum setting.

•

Adjust L1 until the IF-signal for maximum setting.

•

Readjust

L10, L7

and L1 until there is no more improvement for the maximum settings.

IF Measurement Point

CF4

CF2

CF3

Figure 1

L1

L2

L10

L12

L7

VR1

L13

IC1

R21

Unsolder Clip

Unsolder Clip

Figure 2

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4) With the same oscilloscope setup as in procedure #3, press the

ANTENNA

button and select

ANTENNA

port

#1. Check that the IF-signal is reduced by a minimum of 40 dB.

5) Connect the signal generator to

ANTENNA

port #1. With the same oscilloscope setup as in

procedure #3, adjust L2 until the IF-signal is at maximum setting. Press the

ANTENNA

button and

select

ANTENNA

port #2. Check that the IF-signal is reduced by a minimum of 40 dB.

NOTE:

Return to step #3 and perform the same alignment procedure but substitute L2 for L1. Continue to

align

L10, L7, L2

, and L1, until there is no improvement in IF-level maximum level between the two antenna

ports, and that the isolation between the two ports is greater that 40 dB.

Alignment of IF Section:

6) Connect an RF signal generator to

ANTENNA

port #1 and set to:
Amplitude = 45 dBu
Pilot tone = off
Modulation = off
Frequency = 98.000 MHz.

Press the

ANTENNA

-button and select

ANTENNA

port #1. Press the IF-button to select

IF WIDE

.
With the same oscilloscope setup as in procedure #3, check that the IF-signal had increased
approximately 3 dB compared to

IF NARROW

.

Remove the oscilloscope probe from the common point between CF3 and CF4

.

7) Connect an RF signal generator to

ANTENNA

port #1 and set to:
Amplitude = 70 dBu
Pilot tone = off
Modulation = off
Frequency = 98.000 MHz.

Adjust

L13

(or VR1) until the centre-tune LED turns on. Fine adjust

VR1

so that it lights from

approximately 97,965 MHz. to 98,035 MHz equally.

Alignment of Audio Section:

8) Set the

S400

as the following:

Press the IF-button to select

IF WIDE

.

Press the

ANTENNA

-button and select

ANTENNA 1

.

Press the

MONO/MUTE

-button to

MUTE OFF MONO

.

Press the

BLEND

-button to

BLEND OFF.

Press the

BANDWIDTH

-button to

BANDWIDTH WIDE.

Tune the

S400

to 98.00 MHz.

9) Connect an audio AC voltmeter with decibel display to both the right and left audio output jacks. Set
the AC-voltmeter to negative 30 dB range.

Leave the audio AC-voltmeter attached to the S400

audio output jacks until told to remove it.

Then connect an RF signal generator to

ANTENNA

port #1 and set to:
Amplitude = 45 dBu
Pilot tone = on (19 kHz @ 10%)
Modulation = off
Frequency = 98,00 MHz

10) Adjust L3 for a minimum 19 kHz output at the right audio jack.

11) Adjust L4 for a minimum 19 kHz output at the left audio jack

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12) With the audio AC-voltmeter connected as in procedure #9, select 0 db range for both channels.
Connect an RF signal generator to

ANTENNA

port #1 and set to:
Amplitude = 65 dBu
Pilot tone = on (19 kHz @ 10%)
Modulation = 100% (including pilot tone) [1kHz @ +/- 75 kHz L+R and L-R].
Frequency = 98,000 MHz.

13) Set the

S400

as the following:

Press the IF-button to select

IF WIDE

.

Press the

ANTENNA

-button and select

ANTENNA 1

.

Press the

MONO/MUTE

-button to

MUTE ON STEREO

.

Press the

BLEND

-button to

BLEND OFF.

Press the

BANDWIDTH

-button to

BANDWIDTH WIDE.

Tune the

S400

to 98.00 MHz.

14) Check that the audio output is approximately 0 dB +/- 1 dB (775 mV rms) in both right and left output
jacks.

1. Turn the variable capacitor C37 so that the capacitor fins do not mesh, then switch off the modulation in the right side of the
RF signal generator. Adjust

L12

until minimum audio output is measured in the right side.

Record this minimum output

level

.

2. Switch on the modulation in the right side of the RF signal generator. Switch off the modulation in the left side of the RF
signal generator. Adjust L12 until minimum audio output is measured in the left side.

Record this minimum output level

.

Use the side with the worst channel separation to adjust L12, by repeating the above two steps.

After adjusting L12 adjust C37 to minimum output level (maximum channel separation).

Channel separation should be 45 dB (+/- 5 dB).

15) Press the IF-button to select

IF NARROW

.

Check that the channel separation drops approximately 10 dB (+/- 5dB) at the audio output jacks.

16) Press the

BLEND

-button to select

BLEND ON

.

Check that the channel separation drops to approximately 15 dB. (+/- 3 dB) at the audio output jacks.

Remove the audio AC-voltmeter from the audio output jacks, as well as the RF signal generator
form the antenna port.

17) Set the

S400

to default settings for the tuner as the following:

Press the IF-button to select

IF WIDE

.

Press the

ANTENNA

-button and select

ANTENNA 1

.

Press the

MONO/MUTE

-button to

MUTE ON STEREO

.

Press the

BLEND

-button to

BLEND OFF.

Press the

BANDWIDTH

-button to

BANDWIDTH WIDE.

After 10 sec. the settings will be stored.

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L1

L2

L10

L12

L7

VR1

L13

IC1

R21

Unsolder

Clip

Unsolder Clip

CF4

CF2

CF3

L14

C37

L3

L4

RIGHT

LEFT

ANTENNA 2

ANTENNA 1

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