BELINEA 10 55 70 Service Manual Download Page 36

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3.10. Audio Amplifier

The R/L audio signals are supplied through a

the Main Board at connector

and

The audio

signals are impedances by

and

The

R/L audio signals then enter an

audio pre-am-

plifier

providing variable sound control gain. Separate

gain control voltage for the two pm-amplifier channels are
provided by R912 from the 1007

DAC which is

loaded by microcontroller via the

bus.

outputs of the

audio pre-amplifier are fed to

a hybrid power amplifier

type

through resistors

and capaci-

tor

amplifier the audio signal to around

the outputs are AC coupled to the speaker via

and C924.

The R/L audio signals are supplied through a

the Main Board at connector

and

The audio

signals are impedances by

and

The

R/L audio signals then enter an

audio pre-am-

plifier

providing variable sound control gain. Separate

gain control voltage for the two pm-amplifier channels are
provided by R912 from the 1007

DAC which is

loaded by microcontroller via the

bus.

outputs of the

audio pre-amplifier are fed to

a hybrid power amplifier

type

through resistors

and capaci-

tor

amplifier the audio signal to around

the outputs are AC coupled to the speaker via

and C924.

Summary of Contents for 10 55 70

Page 1: ......

Page 2: ...Notes Belinea IO 55 70 Service Manual...

Page 3: ...poorly soldered connections Check the entire board surface for solder splashes and bridges Check the inter board wiring to ensure that no wires are pinched or coated with high wattage resistors Check...

Page 4: ...r receptacle and the retaining screw Try both slots if necessary to locate the hot side of the line The lamp should light at normal brilliance if the screw is at ground potential r Leakage Current Hot...

Page 5: ...nal Disassembly Left Side O 2 l 2 4 Removing the Neck Board and Main Board 2 2 2 5 Removing the Control Board 2 2 Part 2 Non VA Version 2 6 Removing the Rear Cover 2 3 2 7 Internal Disassembly Right S...

Page 6: ...the two cable ties indicated to free the cables Refer to the figure 2 2 D 5 Disconnect the degaussing coil from the Main Board Refer to the figure 2 2 Q 6 Release the cable wire indicated to free the...

Page 7: ...cket Refer to the figure 2 4 A figure 2 4 Remove the Control Panel Figure Z 5 Remove the Neck Board and Main Board 2 Remove the two Lock Caps from the nylon ties Refer to the figure 2 5 A 3 Remove the...

Page 8: ...2 9 0 5 Remove the nylon revets holding from Bezel Refer to the figure 2 9 E 6 7 8 9 Disconnect the ribbon cable from the Logic Board and the cable from the CRT connected to the rear side of the logi...

Page 9: ...from the metal casing of the neck board Refer to the figure 2 10 A 2 Remove the two Lock Caps from the nylon ties Refer to the figure 2 10 B 3 Remove the Neck Board from the CRT 4 Remove the Main Boa...

Page 10: ...Notes c 1 2 5...

Page 11: ...n Circuit 3 3 Video Amplifier I 3 11 Microprocessor and Sync Processing 3 12 Audio Amplifier 3 12 Part 2 Non VA Version 3 6 Sw itching Power Supply 3 13 3 7 The Deflection Circuit 3 15 3 8 Video Ampli...

Page 12: ...sformer T3 is released into the secon dary coil and is regulated through the various output loops and filters and converted to the required DC output In addition to this at the appropriate time the wi...

Page 13: ...is controlled by a logic pulse and lasts approximately 6 six seconds When tran sistor Ql enters the OFF stale and the relay returns to N O to terminate the auto degaussing operation is completed 3 1 2...

Page 14: ...balance of different modes can be in dividually adjusted by changing the VDC level at pin 5 The vertical size of different mode can be indi vidually adjusted by changing the VDC level at pin8 The ver...

Page 15: ...1 1 HRET iv WET I CIRCUIT Q503 Q505 Q509 A X RAY CONTROL I I 4 I CIRCUIT Q370 Q371 L I I I II t H SdC 1 HSYNC 7 c COMBINE0 HORKONTAL 6 MRTICAL PRoCESSof WrTH GEOMETRY CONTRol DYNAMIC Pocus CIRCUIT T4...

Page 16: ...coupled power amplifier IC202 This is 8 simple voltage to current in verting amplifier using R203 to derive a volt age proportional to the current in the dcflcction winding of the yoke This voltage i...

Page 17: ...1 across the 15V and 15V supplies This causes the primary current to increase linearly until such time as 4310 turns off hence storing a predetermined amount of flux energy in the transformer As 43 10...

Page 18: ...e oscillation frequency set by the oscillator at L and C d t4 t5 Period At t4 the voltage of C is 0 After this it is recharged in the opposite direction and this voltage exceeds the voltage of the pow...

Page 19: ...flyback pulse seen across Q301 and the smaller variable flyback pulse seen across C307 As the current flowing in the yoke is proportion to this differ ence the deflection current and therefore the VDM...

Page 20: ...e voltage at a constant 26kV a regulation system is required This is achieved using a buck regu lation stage formed by a ICP2 driving a FET synchronized by the horizontal oscillator The ICP2 has an er...

Page 21: ...passing though the buffer collector of Q353 output to Q354 and Q355 Darlington current amplification though L304 to ad just the current though H DY s current value achiev ing size control In addition...

Page 22: ...ation generated by IC502 can be injected via diodes D513 0514 and D515 IC 501 amplifies the video signals to around 35Vpp The outputs are AC coupled to the CRT cathodes via C523 C5 12 and C513 In orde...

Page 23: ...al frequency IC701 is clocked and reset by the horizontal sync pulse and the HDR line If any sync pulse is not matched by a HDR pulse then an interrupt is created on the MODEC line When power is distu...

Page 24: ...y coil and is regulated through the various output loops and filters and converted to the required DC output In addition to this at the appropriate time the windings pin 1 pin2 supply Pin 7 of IC2 wit...

Page 25: ...ontrolled by a logic pulse and lasts approximately 6 six seconds When tran sistor Ql enters the OFF state and the relay returns to N O to terminate the auto degaussing operation is completed 3 6 2 Sus...

Page 26: ...making the V OUT PUT at Pin 15 also similar As long as the ratio of the width of active display to total display is similar then V SIZE will be similar The internal curmnt source is controlled by the...

Page 27: ...F JUSY c COMBINED HORKONTM 6 r V E R T I C A L P R O C E S S O R CURCUIT ToAQ1ozc IC304 v SYI LOGIC CIRCUIT Icml 7 10 lC713 I6 IC303 Q35I Q345 EkY2 I V7 I I I I i o CC RCtJ T b G E O M E T R Y C I R C...

Page 28: ...l output amplifier has a voltage boost circuit to triple the positive supply volt age during retrace in order to speed up flyback It does this by charging capacitor C202 through diode D212 during the...

Page 29: ...ts of a vertical sawtooth wave generator horizontal sawtooth wave gen erator horizontal osciliator circuit vertical os cillator circuit APC circuit phase regulator circuit X RAY circuit and drive ampl...

Page 30: ...scillation circuits If the current is suddenly cut off then the polarity of the inverse voltage generated at L will be as shown in Figure 3 21 b This voltage is viewed as the source voltage and will c...

Page 31: ...ith C31 I and the deflection yoke is another indicter L303 This is a saturating in dictor that is biased with a permanent magnet Consequently this device has a linearity that is higher for current flo...

Page 32: ...p amnl _________ horizontal scan ferquencies D308 and D309 set up a positive and a negative supply rail with respect to the main B supply Q352 acts as a constant current source that can be programmed...

Page 33: ...age secondary cmnt flowing exceed 46OmA this voltage begins to drop below this threshold Thus a signal is generated which can be fed to video amplifier for automatic beamcmnt limiting ABL I is fed int...

Page 34: ...half of IC504 This takes the trailing edge of the horizontal sync pulse differentiates it through C531 then squares it via the monostable feedback action of C525 and RX3 to provide a precise length di...

Page 35: ...ives the sync selection circuits IC708 is used to set the polarity of the incoming sync signals IC703 allows the micro to sample the vertical and horizontal syncs and to select the correct polarity on...

Page 36: ...11 IC902 amplifier the audio signal to around 1 5W maximun the outputs are AC coupled to the speaker via C920 and C924 The R L audio signals are supplied through a P905 directly to the Main Board at c...

Page 37: ...ification 4 4 Video Noise 4 4 Power Saving Check 4 4 Audio Power Amplifier Check 4 4 DDC l 2 Data Writing4 4 4 Part 2 Non Version 4 21 4 22 4 23 4 24 4 25 4 26 4 27 4 28 4 29 4 30 4 31 4 32 4 33 4 34...

Page 38: ...tor 0 Digital multimeter Cl Degausser Data Line H Freq kHz V Freq Hz Pixel Rate MHz Hor FP J Ls A Hor Sync p B Her BP p C Hor Active p D Her Total ps E Ver FP ms A Ver Sync ms B Ver BP ms C Ver Active...

Page 39: ...ake sure that the display size and linearity are in spec 4 Input timing in primary mode and the white balance automatic adjust some item as blow a Input no video pattern in primary mode and set up bri...

Page 40: ...y Configures vertical linearity as less than 8 6 PINCUSHION Sets left and right pincushion distortion to less than 1 5mm 7 KEYSTONE Sets upper and lower keystone distortion to less than 15mu l 8 PARAL...

Page 41: ...aving Check 1 Input cross hatch pattern in primary mode 2 Turn OFF H Sync signal the power indicator LED have to change the emitting color from green to orange then turn ON H Sync signal again the pic...

Page 42: ...horoughly degauss the entire screen with a manual degausser before proceeding with tests 5 All test should be performed with the rated power supply voltage unless otherwise specified The preset timing...

Page 43: ...Input no video pattern in primary mode and set up brightness of raster white balance get the x y value is x 0 346 0 01 y o 359sK Ol b Input a full white pattern in primary mode and set up 5000 degrees...

Page 44: ...istortion to less than I 5mm 8 PARALLELOGRAM Sets parallelogram distortion to less than l Smm Conclusion of automatic alignment 4 32 Image Performance Verification Inputeachofthepresettimingsandcheckt...

Page 45: ...e the emitting color from green to orange then turn ON H Sync signal again the picture shall be vis ible 3 Turn OFF V Sync signal the power indicator LED have to change the emitting color from green t...

Page 46: ...Notes L t 4 9 L...

Page 47: ...Display Area 5 7 5 8 Misconvergence 5 8 5 9 Poor Regulation 5 9 5 10 No Audio Amplifier 5 l 0 Part 2 Non VA Version 5 11 No Display at Power on 5 11 5 12 No X ray Operation 5 l 2 5 13 No Video Operat...

Page 48: ...A Version 5 1 No Display at Power on Orange power on Check I O cable Check IC707 Q8 R59 QP4 QP5 QP6 and RP18 Logic PCB to Power Supply PCB Conjunction of wire Check IC506 and IC504 O k Check Power Sup...

Page 49: ...c 5 2 No X ray Operatidn No X ray operation Check F B T CheckQ370 Q371 ZD31 C R4Al R4AO R47O R471 Check Q8 R59 R75 and Ok 5 2...

Page 50: ...5 3 No Video Operation No Video operation at Power ON 1 Check IC504 IC506 IC503 and I O cable Check Q502 Q504 Q506 I END I 5 3 h...

Page 51: ...5 4 Poor Vertical Linearity Check firm ware Check R411 R487 Check IC308 R480 R4811 R488 and R489 Check IC202 R203 and R204 5 4...

Page 52: ...Linearity I Horizontal linearity over 10 I Check Logic firm ware and Logic Circuit Check Q350 Q302 Q309 and RL301 Check C311 C324 313 for current leakage or capacity over 5 Check function Check Q309 R...

Page 53: ...5 6 Poor Uniformity Check video amp circuits Check Degauss circuit and PTCR Check power supply circuits Change C R T 5 6...

Page 54: ...isplay Area I Tilt is greater than 1 75mm 1 of cross hatch Check C R T mechanical position Readjust C R T mounting and bezel Check pin1 1 OV SV of IC307 and pin7 of IC302 out voltage is 15V 15V and Q3...

Page 55: ...L 5 8 Misconvergence I Misconvergence over 0 3 0 4mm I Check 4 pole and 6 pole Check CRT...

Page 56: ...5 9 Poor Regulation QP3 LPl and DP3 square wave is 6OV 180V ICP2 pin 2 sawtooth pin 5 DC 6 5v Check QP2 and FB I E N D I 5 9...

Page 57: ...5 10 No Audio Amplifier No Audio Operation at Power on 1 Check IC901 P903 Check IC902 P901 Check SW901 Check Speaker and check SW903...

Page 58: ...VA Version 5 11 No Display at Power on Check I O cable Check IC707 Q8 Fi59 Q308 R312 R305 IC301 and Logic PCB to Power Supply PCB Conjunction of wire Check IC506 and IC504 Ok Check Power Supply I I E...

Page 59: ...5 12 No X ray Operation Check F B T Check lC303 0373 normal of level Check IC304 I Retry power on 5 12...

Page 60: ...5 13 No Video Operation INo Video operation at Power ON I YES r Check Q501 Q502 Q503 Q504 Q505 Q506 I END I 5 13...

Page 61: ...I c 5 14 Poor Vertical Linearity Check firm ware Check IC307 Check C387 and IC304 I Check IC202 D210 D211 R204 R209 R210 5 l 4...

Page 62: ...5 15 Poor Horizontal Linehy Horizontal linearity over 10 I Check Logic fim ware and Logic Circuit Check Q35O Q302 Q309 and IX301 Check C311 C324 C313 for current leakage or capacity over 25 i END 5 15...

Page 63: ...5 16 Poor Uniformity Check video a p circuits Check Degauss circuit and PTCR Check power supply circuits Change C R T 1 1 1 I I End I 5 16...

Page 64: ...5 17 Tilted Display Area A Check Check C R T mechanical position Readjust C R T mounting and bezel Check pin1 1 OV 5V of IC307 and pin7 of IC302 out voltage is 15V 15V and Q356 Q357 END I 5 l 7...

Page 65: ...5 18 Misconvergence I Misconvergence over 0 3 0 4mm 1 b Check 4 pole and 6 pole Check CRT I END I 5 18...

Page 66: ...5 19 Poor Regulation Regulation over 1 5mm w ICP2 pin 2 sawtooth pin 5 DC 6 5V Check QP2 and FB I END I 5 l 9...

Page 67: ...I I 5 20 No Audio Amplifier t c No Audio Operation Check IC901 P903 Check IC902 P901 Check SW901 Check Speaker and check SW903 I END I 5 20...

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