Philco PF2908, Service Manual

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Ⅰ
SAFETY PRECAUTION
1. X-RAY RADIATION PRECAUTION
1.1 Excessive high voltage can prod
u
ce 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 29” 29KV
±
500V under 230V AC power source. The high voltage must not exceed 30KV for 29” TV
1.2 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.
1.3
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.
1.4
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.
2. GENERAL SAFETY PRECAUTION
The following are the necessary precautions to be observed before servicing this chassis
WARNING: Service should not be attempted by anyone unfamiliar with the necessary
2.1 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.
2.2
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.
2.3 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.
2.4 Connection wires must be kept away from components with high voltage or high temperature.
2.5 When replacing parts or circuit boards, disconnect the power cord.
2.6 When replacing a high voltage resistor (metal oxide resistor) on circuit board, keep the resistor APP.
10mm (1/2 in.) away from circuit board.
2.7 If any fuse in this TV receiver is broken, replace it with the FUSE specified in the chassis parts list.
2.8 The receiver is designed to operate with 230V (50Hz) AC mains.
3. 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.
Warning!
There are no any repairable components in this TV set. Do not try to make any change to it. High voltage
inside may cause danger.
Ⅱ
SPECIFICATION