Changhong Electric PF2939 Service Manual Download Page 4

SERVICE MANUAL 

4.  When replacing ICs, use specific tools or a static-proof electric iron with small power (below 

35W). 

5.  Do not use a magnetized screwdriver when tightening or loosing the deflection yoke assembly 

to avoid electronic gun magnetized and decrement in convergence of the CRT. 

6.  When remounting the TV chassis, ensure that all guard devices, such as nonmetal control 

buttons, switch, insulating sleeve, shielding cover, isolating resistors and capacitors, are 

installed on the original place. 

7.  Replace blown fuses within the TV with the fuse specified in the parts list. 

8.  When replacing wires or components to terminals or tags, wind the leads around the terminal 

before soldering. When replacing safety components identified by the international hazard 

symbols on the circuit diagram and parts list, it must be the company-approved type and must 

be mounted as the original. 

9.  Keep wires away from high temperature components. 

 

 

PRODUCT SAFETY NOTICE 

CAUTION: FOR YOUR PROTECTION, THE FOLLOWING PRODUCT SAFETY NOTICE 

SHOULD BE READ CAREFULLY BEFORE OPERATING AND SERVICING THIS TV SET. 

1.  Do not slap or beat the cabinet or CRT, since this may result in fire or explosion. 

2.  Never allow the TV sharing a plug or socket with other large-power equipment. Doing so may 

result in too large load, thus causing fire. 

3.  Do not allow anything to rest on or roll over the power cord. Protect the power cord from being 

walked on, modified, cut or pinched, particularly at plugs. 

4.  Do not place any objects, especially heavy objects and lightings, on top of the TV set. Do not 

install the TV near any heat sources such as radiators, heat registers, stove, or other 

apparatus that produce heat. 

5.  Service personnel should observe the SAFETY INSTRUCTIONS in this manual during use 

and servicing of this TV set. Otherwise, the resulted damage is not protected by the 

manufacturer. 

6.  Many electrical and mechanical components in this chassis have special safety-related 

characteristics. These characteristics are often passed unnoticed by a visual inspection and 

the X-ray radiation protection afforded by them cannot necessarily be obtained by using 

replacements rated at higher voltages or wattage, etc. Components which have these special 

safety characteristics in this manual and its supplements are identified by the international 

hazard symbols on the circuit diagram and parts list. Before replacing any of these 

components read the parts list in this manual carefully. Substitute replacement components 

which do not have the same safety characteristics as specified in the parts list may create 

X-ray radiation. 

Summary of Contents for PF2939

Page 1: ...FILE NO SM CTV G 005 COLOR TELEVISION SERVICE MANUAL MODEL NO PF2939 CHASSIS NO CH 16CD Please read this manual carefully before service...

Page 2: ...Maintenance 3 KEY ICS AND ASSEMBLIES 4 SYSTEM BLOCK DIAGRAMS 5 Structure Block Diagram 5 Block Diagram for Supply Voltage System 6 SERVICE DATA 7 Technical Data of Key ICs 7 Service Data of Key ICs 2...

Page 3: ...ICE 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...

Page 4: ...ing a plug or socket with other large power equipment Doing so may result in too large load thus causing fire 3 Do not allow anything to rest on or roll over the power cord Protect the power cord from...

Page 5: ...V set on a stable and level surface Do not place the set near or over a radiator or heat register or where it is exposed to direct sunlight 2 Do not install the TV set in a place exposed to rain water...

Page 6: ...Model No Function Description 1 N201 OM8373PS CH05T1632 UOC 2 N202 AT24C16 EEPROM 3 N301 TA1343N Audio processor 4 N401 TDA8350 Vertical output circuit 5 N361 TDA8944J Sound power amplifier 6 N901 TA1...

Page 7: ...8656 IC801 And BCK 24217L T803 5V 1 15V 1 3 3V 15V 2 145V 8V Circuit for Buttons On The TV Remote Sensor HS0038 Remote control 200V Monitor Out V OUT TDA8350Q N401 UOC N201 CRT Drive H Drive Q501 T501...

Page 8: ...SERVICE MANUAL Block Diagram for Supply Voltage System Fig 2 Block Diagram for Supply Voltage System for CH 16CD Chassis 6...

Page 9: ...rcuit Integrated luminance delay line with adjustable delay time Picture improvement features with peaking with variable positive negative overshoot ratio black stretching and Dynamic Skin Tone Contro...

Page 10: ......

Page 11: ...SERVICE MANUAL 9 4 Block Diagram...

Page 12: ...SERVICE MANUAL 10 5 Refer to Table 2 about Functions and Service Data of the IC s Each Pin Fig 5...

Page 13: ...les Data Retention 100 Years Automotive Grade and Extended Temperature Devices Available 8 Pin and 14 Pin JEDEC SOIC and 8 Pin PDIP Packages 2 Description The AT24C01A 02 04 08 16 provides 1024 2048 4...

Page 14: ...SERVICE MANUAL 12 3 Block Diagram Fig 6 4 Refer to Table 3 about Functions and Data of the IC s Pins...

Page 15: ...revents distort Weight 1 22g Typ the signal in large signal condition for woofer channel is also incorporated 1 Features Surround circuit Phase shift surround system 2 modes stereo surround Pseudo ste...

Page 16: ...ect capacitors 0 027 uF between each terminals and GND 11 14 Treble HPF R Treble HPF L HPFs for treble control circuits Connect capacitors 8200 pF between each terminals and GND 12 13 16 Wch output Rc...

Page 17: ...ovides a DC driven vertical deflection output circuit operating as a highly efficient class G system and an East West driver for sinking the diode modulator current Few external components Highly effi...

Page 18: ...944J is printed circuit board PCB compatible with all other types in the TDA894x family One PCB footprint accommodates both the mono and the stereo products 2 Features Few external components Fixed ga...

Page 19: ...a microcomputer it is possible to check each input output channel self diagnosis This IC has the same pin assignments as the TA1218AN SDIP42 a 2 channel output version of the TA1219AN so these chips a...

Page 20: ...SERVICE MANUAL 18 2 Block Diagram Fig 11 3 Refer to Table 7 about Functions and Service Data of TA1219AN s Pins...

Page 21: ...ent limiting under voltage lockout with hysteresis over voltage protection and thermal shutdown protects the power supply during the normal overload and fault conditions Low current startup and a low...

Page 22: ...ontrol circuit 5 OCP FB Over current protection detection signal voltage limiting signal input 3 2 Pin function for STR F6654 Pin No Symbol Function Description 1 OCP FB Over current protection detect...

Page 23: ...mA current sinking capability for direct drive of LEDs 4 235 6 67 2 19 12 Analog ground of Teletext decoder and digital ground of TV processor 0 0 0 13 Internally connected 2 30 4 61 2 84 14 2nd supp...

Page 24: ...3 45 5 07 2 82 45 2nd RGB YUV insertion input 1 68 4 68 2 84 46 2nd R input V R Y input PR input 2 5 5 04 2 86 47 2nd G input Y input 2 5 4 88 2 82 48 2nd B input U B Y input PB input 2 5 5 04 2 86 49...

Page 25: ...ge V Positive Resistance 20K Negative Resistance 20K 1 Offset canceling filter 4 6 7 26 2 757 2 4 4 6 7 31 2 769 3 3 4 6 7 26 2 774 4 2 4 6 7 25 2 771 5 1 4 6 7 16 2 763 6 Lch input 4 5 7 08 2 764 7 G...

Page 26: ...ble 6 Functions and Service Data of TDA8944J N361 s Pins Digital Multimeter Pin No Functions Description Reference Voltage V Positive Resistance 20K Negative Resistance 20K 1 Negative loudspeaker term...

Page 27: ...ns1 5 09 3 88 2 79 11 RinS1 5 1 4 01 2 79 12 CinS1 0 04 3 97 2 64 13 LinS2 5 08 4 03 2 79 14 Y VinS2 5 13 3 97 2 79 15 RinS2 5 11 3 97 2 79 16 CinS2 0 04 4 06 2 63 17 I O1 7 3 4 31 2 51 18 I O2 7 13 4...

Page 28: ...ital Multimeter Pin No Functions Description AC Power 110v 50 60Hz Reference Voltage V AC Power 220v 50 60Hz Reference Voltage V Positive Resistance 20K Negative Resistance 20K 1 D 152 309 2 2 S 0 062...

Page 29: ...SERVICE MANUAL Waveforms of Key Points N201 s Pin2 N201 s Pin3 27...

Page 30: ...SERVICE MANUAL N201 s Pin22 N201 s Pin32 28...

Page 31: ...SERVICE MANUAL N201 s Pin33 N201 s Pin34 29...

Page 32: ...SERVICE MANUAL N201 s Pin38 N201 s Pin42 30...

Page 33: ...SERVICE MANUAL N201 s Pin43 N201 s Pin59 31...

Page 34: ...SERVICE MANUAL N401 s Pin5 N401 s Pin9 32...

Page 35: ...SERVICE MANUAL N401 s Pin11 33...

Page 36: ...least 15 minutes 1 Demagnetize the CRT and cabinet using a degaussing coil 2 Set the brightness and contrast to maximum 3 Receive the green raster test pattern 4 Loosen the clamp screw holding the de...

Page 37: ...ement 4 pole magnet and 6 pole magnet interact each other resulting in complicating and dot movement Circumference convergence adjustment 1 Loosen the clamping screw of the defection yoke slightly to...

Page 38: ...are thoroughly checked and corrected before the TV outgoing Therefore the TV should operate normally and deliver proper color pictures upon installation However several minor adjustments may be requi...

Page 39: ...ence Adjustment procedures 3 Supply Voltage Adjustment Caution B voltage has close relation to high voltage To avoid X ray radiation B voltage should be 145V 1 AC power supply to 110 240V 50 60Hz 2 Co...

Page 40: ...on byte 8 See Option bit set 6 PAR Set to optimum Parallelogram correction 60Hz 6 BOW Set to optimum Bow correction 60Hz 6 HSH Set to optimum Horizontal shift 60Hz 6 EWW Set to optimum East west width...

Page 41: ...1CON 80 Contrast in Normal mode 1BRI 50 Brightness in Normal mode 1COL 50 Color in Normal mode 1SHP 50 Sharpness in Normal mode 2CON 100 Contrast in Movie mode 2BRI 40 Brightness in Movie mode 2COL 60...

Page 42: ...nal FORCE 60Hz 1 3 OP_SOUND_EFFECT Audio options 1 Yes 0 No 1 4 OP_SIF UOC Pin32 as sound IF input 1 Yes 0 No 0 5 OP_IDENT_TXT12 1 TXT12 Ident detection 0 SL Ident detection 1 6 OP_COMB_FILTER TC90A53...

Page 43: ...Yes 0 No 0 5 OP_BSCREEN Black screen when changing channels 1 Yes 0 No 0 6 OP_WOOFER_MAIN Woofer available on main channel 1 Yes 0 No 0 OP5 7 OP_CHANNEL _LABEL Channel label 1 Yes 0 No 1 0 OP_FMWS FM...

Page 44: ...trix 1 USA 0 Japan 0 3 OP_FORF According to Datasheet 1 4 OP_FORS According to Datasheet 0 5 OP_CHILD_LOCK Child lock 1 Yes 0 No 1 6 OP_LANG_DEF0 1 OP8 7 OP_LANG_DEF1 Auto outgoing language option set...

Page 45: ...ed Connector XPK03 Wired Connector XPY01 Wired Connector XPY03 CRT s Ground Wire B Wire Grey A Wire Red Speaker Speaker Control Buttons Board Assembly Wired Connector AD 03 600 T300D Wired Connector X...

Page 46: ...CIRCUIT DIAGRAM OF 29F51PH...

Page 47: ...Circuit Diagram of 29F51PH...

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