LG L320-BN, Service Manual

 1-2

SECTION 1 GENERAL

SAFETY PRECAUTIONS

1. PRODUCT SAFETY SERVICING GUIDELINES FOR CAMERA PRODUCTS

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 THOR-

OUGHLY 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 REIN-

STALLED PER ORIGINAL DESIGN. BE SURE THAT THE SAFETY PUR-

POSE 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 IN-

SULATION (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 

PROTRUNING METAL SURFACES MUST BE AVOIDED.

6.  ALL CRITICAL COMPONENTS SUCH AS FUSES, FLAMEPROOF RESIS-

TORS, CAPACITORS, ETC. MUST BE REPLACED WITH EXACT FAC-

TORY 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. LEAK-

AGE 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 WITH-

OUT DANGER OF ELECTRICAL SHOCK. DO NOT USE A LINE ISOLA-

TION TRANSFORMER DURING THIS TEST USE AN A.C. VOLT- ME-

TER, 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 

AKNOWN GOOD EARTH GROUND (WATER PIPE, CON- DUIT, ETC.) 

AND THE EXPOSED METALLIC PARTS, ONE AT A TIME. MEASURE THE 

A.C. VOLTAGEACROSS 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 TRI-

ANGLE 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 PO-

TEN- 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. OP-

ERA- 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 DE-

SIRABLE LEVELS.

2.  ONLY FACTORY SPECIFIED C.R.T. ANODE CONNECTORS MUST BE 

USED. DEGAUSSING SHIELDS ALSO SERVE AS X-RAY SHIELD IN 

COLOR SETS, ALWAYS RE-INSTALL THEM.

3.  IT IS ESSNTIAL THAT SERVICE PERSONNEL HAVE AVAILABLE AN AC-

CURATE 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 RECORDER 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 LON-

GER THAN 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 SCRATCH-

ING 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 PALCEMENT WHERE DRAPERIES MAY OBSTRUCT REAR 

VENTING. THE CUSTOMER SHOULD ALSO AVOID THE USE OF DEC- 

ORATIVE SCARVES OR OTHER COVERINGS WHICH MIGHT OB-

STRUCT 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 EQUIVA-

LENT 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 RE-

CEIVER 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.

GOOD EARTH 

GROUND SUCH AS 

THE WATER PIPE. 

CONDUIT. ETC

PLACE THIS PROBE 
ON EACH EXPOSED 
METAL PART

A.C. VOLTMETER