Changhong Electric 21NF55, Руководство по обслуживанию, Страница: 4 / 83

SERVICE MANUAL
2
INSTRUCTIONS FOR SERVICE SAFETY AND MAINTENANCE
WARNING: BEFORE SERVICING THIS CHASSIS, READ THE
“
X-RAY RADIATION PRECAUTION
”
,
“
SAFETY PRECAUTION
”
AND
“
PRODUCT SAFETY NOTICE
”
INSTRUCTION BELOW.
X-RAY RADIATION PRECAUTION
1. The EHT must be checked every time the TV is serviced to ensure that the CRT does not emit
X-ray radiation as result of excessive EHT voltage. The maximum EHT voltage permissible in any
operating circumstances must not exceed the rated value. When checking the EHT, use the High
Voltage Check procedure in this manual using an accurate EHT voltmeter.
2. The only source of X-RAY radiation in this TV is the CRT. The TV minimizes X-RAY radiation, which
ensures safety during normal operation. To prevent X-ray radiation, the replaceme nt CRT must be
identical to the original fitted as specified in the parts list.
3. Some components used in this TV have safety related characteristics preventing the CRT from
emitting X-ray radiation. For continued safety, replacement component should be made after
referring the PRODUCT SAFETY NOTICE below.
4. Service and adjustment of the TV may result in changes in the nominal EHT voltage of the CRT
anode. So ensure that the maximum EHT voltage does not exceed the rated value after service
and adjustment.
SAFETY PRECAUTION
WARNING: REFER SERVICING TO QUALIFIED SERVICE PERSONNEL ONLY.
1. The TV has a nominal working EHT voltage. Extreme caution should be exercised when working
on the TV with the back removed.
1.1 Do not attempt to service this TV if you are not conversant with the precautions and procedures for
working on high voltage equipment.
1.2 When handling or working on the CRT, always discharge the anode to the TV chassis before
removing the anode cap in case of electric shock.
1.3 The CRT, if broken, will violently expel glass fragments. Use shatterproof goggles and take extreme
care while handling.
1.4 Do not hold the CRT by the neck as this is a very dangerous practice.
2. It is essential that to maintain the safety of the customer all power cord forms be replaced exactly
as supplied from factory.
3. Voltage exists between the hot and cold ground when the TV is in operation. Install a suitable
isolating transformer of beyond rated overall power when servicing or connecting any test
equipment for the sake of safety.
4. When replacing ICs, use specific tools or a static-proof electric iron with small power (below 35W).