NAD T 572, Service Manual

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CAUTION : DO NOT ATTEMPT TO MODIFY THIS PRODUCT IN ANY WAY,
NEVER PERFORM CUSTOMIZED INSTALLATIONS WITHOUT MANUFAC-
TURER’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 PROTEC-
TION 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 CIR-
CUIT MODIFICATIONS.
7. AFTER RE-ASSEMBLY OF THE SET ALWAYS PERFORM AN A.C.
LEAKAGE TEST ON ALL EXPOSED METALLIC PARTS OF THE CABI-
NET, (THE CHANNEL SELECTOR KNOB, ANTENNA TERMINALS. HAN-
DLE 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. VOLT-
METER, HAVING 5000 OHMS PER VOLT OR MORE SENSITIVITY, IN
THE FOLLOWING MANNER; CONNECT A 1500 OHM 10 WATT RESIS-
TOR, PARALLELED BY A .15 MFD. 150.V A.C TYPE CAPACITOR
BETWEEN A KNOWN GOOD EARTH GROUND (WATER PIPE, CON-
DUIT, 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 MAG-
NITUDE TO CONSTITUTE A RISK OF ELECTRIC SHOCK.
THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIAN-
GLE 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 PER-
SONNEL COVER THE SUBJECT OF X-RADIATION. THE ONLY POTEN-
TIAL SOURCE OF X-RAYS IN CURRENT T.V. RECEIVERS IS THE PIC-
TURE 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. OPERA-
TION AT HIGHER VOLTAGES MAY CAUSE A FAILURE OF THE PIC-
TURE TUBE OR HIGH VOLTAGE SUPPLY AND, UNDER CERTAIN CIR-
CUMSTANCES, MAY PRODUCE RADIATION IN EXCESS OF DESIR-
ABLE 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 CALIBRA-
TION 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 ORGA-
NIZATION REVIEW TEST PROCEDURES SO THAT VOLTAGE REGU-
LATION IS ALWAYS CHECKED AS A STANDARD SERVICING PROCE-
DURE 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 EXCES-
SIVE 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 INTE-
GRAL 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, CUBBY-
HOLE 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 RADIA-
TORS WHERE STEAM LEAKAGE IS A FACTOR, ETC.
3. AVOID PLACEMENT WHERE DRAPERIES MAY OBSTRUCT REAR
VENTING. THE CUSTOMER SHOULD ALSO AVOID THE USE OF DEC-
ORATIVE SCARVES OR OTHER COVERINGS WHICH MIGHT
OBSTRUCT VENTILATION.
4. WALL AND SHELF MOUNTED INSTALLATIONS USING A COMMER-
CIAL 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 HAZ-
ARDS 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 SIN-
GLE OUTLET CAN LEAD TO DISASTROUS CONSEQUENCES TO
HOME AND FAMILY.
PRODUCT SAFETY SERVICING GUIDELINES FOR VIDEO PRODUCTS
A.C. VOLTMETER
GOOD EARTH GROUND
SUCH AS THE WATER
PIPE. CONDUIT. ETC PLACE THIS PROBE
ON EACH EXPOSED
METAL PART