COLOUR TELEVISION RECEIVER SERVICE MANUAL SPECIFICATION - Safely Precaution - X-RAY RADIATION PRECAUTION

Oct 12, 2026

Service manual specification for a Colour Television Receiver (TV4K-NICAM/A2), covering PAL/SECAM B/G, I and NICAM/A2 system, power input and consumption, tuner voltage synthesizer tuning, and receiving channel ranges with program memory and audio/video interface details. Includes safety precautions focused on preventing X-ray hazards from excessive high voltage, required high-voltage checking procedures, proper picture-tube replacement type matching, and general chassis servicing safety before adjustments such as B+ and focusing for optimal display.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages9

Reading Time23 min

AccessFree to download

X-RAY RADIATION PRECAUTION

SAFETY PRECAUTION

GENERAL ADJUSTMENT

AUTOMATIC DEGAUSSING

B+ ADJUSTMENT

HIGH VOLTAGE CHECK

FOCUSING

Service controlled Function

TV4K-NICAM/A2/TXT COLOUR TELEVISION RECEIVER SERVICE MANUAL SPECIFICATION l SYSTEM PAL/SECAM,B/G,I,NICAM/A2 l POWER INPUT AC 170-245V(50/60Hz) l POWER CONSUMPTION 85W l AERIAL IMPEDANCE 75OHM UNBALANCED l TUNER VOLTAGE SYNTHESIZER TUNING l RECEIVING CHANNELS VHF-LE2-S6 VHF-H S7-S41 UHF E21-E69 l PROGRAMME MAX.99 PROGRAM MEMORIES l PICTURE TUBE 25”,28”, 110 ° l SOUND OUTPUT 3.0W X2 l SPEAKER 8W 8 OHM X2 l AV JACKS FULL SCART ×2 PDF created with pdfFactory trial [version](version www.pdffactory.com)[ ](version www.pdffactory.com)[www.pdffactory.com](version www.pdffactory.com) CAUTION: Before servicing the chassis, read the “Safely Precaution”.“X-Ray radiation Precaution” and “Product Safety Notice” in this manual. X-RAY RADIATION PRECAUTION 1. Excessive high voltage can produce potentially hazardous X-RAY RADIATION. To Avoid such hazards the high voltage must be specified limit. The normal value of the high voltage of this receiver is 26.5KV +/-2KV under 230V AC power source. The high voltage must not exceed 29KV. 2. Each time a receiver requires servicing the high voltage should be checked following the HIGH VOLTAGE CHECK procedure in this manual. It is recommended the reading of the high voltage be recorded as a part of the service record. It is important to use an accurate and reliable high voltage meter. 3. The primary source of X -RAY RADIATION in this TV receiver is the picture tube. For continued X-RAY RADIATION protection, the replacement tube must be exactly the same type tube as used in this TV receiver. 4. Some parts in this receiver have special safety-related characteristics for X-RAY RADIATION protection. For continued safety, parts replacement should be undertaken only after referring the PRODUCT SAFETY NOTICE below. SAFETY PRECAUTION WARNING: Service should not be attempted by anyone unfamiliar with the necessary Precautions on this receiver. The following are the necessary precautions to be observed before servicing this chassis. 1. Since the power supply circuit of this receiver is directly connected to the AC power line. An isolation transformer should be used during any dynamic service to avoid possible shock hazard. 2. Always discharge the picture tube anode to the CRT conductive coating before handling the picture tube. The picture tube is highly evacuated and if broken, glass fragments will be violently expelled. Use shatterproof goggles and keep picture tube away from the unprotected body while handling. 3. When replacing a chassis in the cabinet, always be certain that all the protective devices are put back in place, such as: nonmetallic control; knobs, insulating covers, shields, isolation resistor-capacitor, network, etc. 4. When replacing parts or circuit boards, disconnect the power cord. 5. When replacing a high voltage resistor (metal oxide resistor) on circuit hoard, keep the resistor APP. 10mm( 1/2 in.) away from circuit board. 6. Connection wires must be kept away from components with high voltage or high temperature. 7. If any fuse in this TV receiver is blown, replace it with the FUSE specified in PDF created with pdfFactory trial [version](version www.pdffactory.com)[ ](version www.pdffactory.com)[www.pdffactory.com](version www.pdffactory.com) the chassis parts list. 8. The receiver is designed to operate with 230V(50Hz) AC mains. PRODUCT SAFETY NOTICE Many electrical and mechanical parts in this chassis have special safety-related characteristics are often passed unnoticed by a visual inspection and the X-RAY RADIATON protection afforded by them cannot necessarily be obtained by using replacement components rated for higher voltage. The use of substitute replacement parts that do not have the same safety characteristics as specified in the parts list may create shock, fire, X-RAY RADIATION or other hazards. GENERAL ADJUSTMENT AUTOMATIC DEGAUSSING An automatic degaussing coil is attached around the picture tu

FAQs

Why does the manual emphasize X-RAY RADIATION PRECAUTION before servicing?

Excessive high voltage can create potentially hazardous X-RAY RADIATION. The manual specifies required high-voltage limits and stresses correct procedures to prevent unsafe conditions during servicing.

What high-voltage limits must be respected for this receiver?

The normal high-voltage value is 26.5KV +/-2KV under 230V AC, and it must not exceed 29KV under any conditions. The manual also notes there is no separate high-voltage adjustment in this chassis.

How is the B+ voltage adjusted and verified?

With the receiver supplied by 230V, 50Hz and tuned to an active channel, B+ is measured (between C641 on the Main P.C. Board) and VR631 is adjusted until B+ is 140.0V +/-1.0V. Contrast, brightness, and color are set to maximum during this adjustment.

Oct 12, 2026

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