Sharp 8C221 Service Manual Download

Page: 39 / 46

Tuner

Figure

Tuner Schematic

SAFETY NOTE:

DISCONNECT THE AC PLUG FROM THE

AC OUTLET BEFORE REPLACING
PARTS

SEMICONDUCTOR

SINKS

S H O U L D B E R E G A R D E D A S P O -

TENT/AL SHOCK HAZARDS WHEN
THE CHASSIS IS OPERATING.

BOTTOM VIEW

V I E W

NOTE

The unit of n&stance

omitted

ohms

M-l

All resistors are

watt, unless

noted.

3 All capacitors

unless otherwise noted

Voltage Measurement Conditions

in parenthesis measured with no Signal.

without parenthesis measured with

w or

All the voltages in each point an?

with

Vacuum Tube Volt Meter..

Waveform Measurement Conditions

bar generator signal of 2 V peak to

applied

at base of

Video Amplifier

BOTTOM VIEW

CA-

-L

BOTTOM VIEW

Summary of Contents for 8C221

Page 1: ... picture tube only when wearing shatter proof goggles and after discharging the high voltage completely X RAY This receiver is designed so that any X ray radiation is kept to an absolute minimum Since certain malfunctions or servicing may produce potentially hazardous radiation with prolonged exposure at close range the following precautions should be observed 1 Do not adjust the high voltage leve...

Page 2: ...he setting up and installation of colour T V receivers The receiver should be positioned in its foal location before degaussing because of possible loss of purity due to the re location of the receiver Because of possible loss of purity caused by the re location of the receiver the cabinet should be positioned in its final location before degaussing MODULE SERVICE PERCAUTIONS 1 DO NOT remove or in...

Page 3: ...ol R206 counter clock wise 4 Observing the indication of VTVM slowly turn RF AGC control R206 clockwise and fix it when the voltage starts to fall 13OV ADJUSTMENT The 13OV Adj control R724 is adjusted at the factory However should readjustment be required proceed as follows 1 Operate receiver for at least 15 minutes 2 Connect positive lead of VTVM to TWO 1 negative lead to chass is ground 3 Rotate...

Page 4: ...onnect voltmeter positive probe to TP603 and negative probe to TP602 on PWB B 2 Rotate Brightness and Contrast controls to maximum 3 Adjust s lb contrast control R671 to obtain a reading of 1 15v PURITYADJUSTMENT Before purity adjustment can be made the receiver should be demagnetized and allow to run with full bright ness without bloom for a minimum of 10 minutes and static convergence must be co...

Page 5: ... pulled out of the cabinet 5 Remove PWB E chassis power PWB retaining screws 6 After all plug connections on PWB E have been discon nection the PWB E chassis can be pulled out of the cabinet 7 When remove the PWB A chassis signal PWB after pull out of the all connections on PWB A and pull out the PWB A chassis PICTURE TUBE ASSEMBLY REMOVAL AND REPLACE MENT 1 2 3 4 5 6 7 8 Remove PWB B and PWB E ch...

Page 6: ...ch long In many instances a small ceramic capacitor approximately lOOOPF connected from the oscilloscope probe to ground will eliminate stray pick up of unwanted signals If used make sure the capacitor does not affect the shape of the response being observed Signal Overload Use of excessive signal from the Sweep Generator can cause overloading of the receiver circuits To determine that this condit...

Page 7: ...h crystal caliblated accuracy OSCOLLOSCOPE IF TEST BLOCKS Shown in Fig 3 VIDEO DETECTOR TEST BLOCK Shown in Fig 4 OUTPUT PADS Shown in Fig 5 A B C A TO TEST POINT loop I N60 47K I5000 CHASSIS Figure 3 IF Test Block Figure 4 Video Detector Test Blodc TO TEST POINT I 001 5 6K CHASSIS SWEEP GENERATOR CHUSi A SIF Sweep Generator Output Pad B PIF Sweep Geneator Output Pad SWEEP GENERATOR SWEEP GENERATO...

Page 8: ...should be correctly fine tuned fine tuning should not be adjusted while performing this tuner check OSCILLOSCOPE With at 1 OV P P calibration connect to terminal TP203 SWEEP GENERATOR Connect output to the tuner aerial terminals using proper matching pad MARKER GENERATOR Connect markers at loosely to Sweep Generator output lead BIAS SUPPLY Apply 7 S volts bias to TP204 Performance Check Starting w...

Page 9: ...ame as Step 1 31 375MHz T206 Adjust T206 Top core alternately for Top co maximum attenuation of 31 375MHz as Det transformer shown on response curve A of Figure 7 Recheck adjustment of I206 Bottom core for response as shown in A Figure 7 Remove the Sweep Generator lead from TP201 and reconnect it to test point on tuner Remove the IF Test Block terminal A from the TP203 and reconnect it to TP201 of...

Page 10: ...3 1 375 Response Curve A 31 376 38 376 Response Curve Figure 7 PIF Transformer and Trap Alignment 10 ...

Page 11: ...ible 36 875MHz marker if necessary without distorting the response cuIye 2 Move the core of T201 to its bottom end of range 3 AFT Transformer 35 40MHz 36 875MHz 1208 Adjust T208 to obtain the maximum amplitude I and response cuve A as shown in Figure 8 4 AFT Discriminator 35 40MHz 36 875MHz T209 Adjust T209 to bring 36 875MHz marker to the centre of S curve B as shown in Figure 8 5 APT Transformer...

Page 12: ...T3Ol T206 cl 0 Q 0207 1200 T205 0 TP206 c l 0 0 0206 0 TP205 0 0 T203 0 00 T202 Q202 0 Q 00205 0204 cl 0 TPOI ouT Figure 9 RF AFT Alignment 12 ...

Page 13: ...und and minimum buzz VIDEOTRAP 4 43MHz ALlGNMENT GENERAL Connect AC power plug through the isolation transformer to power supply STEP 1 PROCEDURE Connect Colour Bar Generator to receiver antenna terminals Switch Pattern control to Colour Bar Position Adjust receiver for normal colour reception 2 Connect Oscilloscope to TP404 3 I Adjust the Video Trap T401 for minimum chroma carria in the Video sig...

Page 14: ...B Bias controls to minimum fully CCW 4 Connect oscilloscope to collector of red output transistor 21001 5 Connect a short clip lead between TP402 and TP403 6 Adjust the Pedestal control R436 to make the pedestal level be aligned with the pulse level A of the waveform drawn on an oscilloscope 7 Adjust the white balance in such manners as in page 4 J J A ______ ______ 1 _____________ DC130V Waveform...

Page 15: ...n Set the Contrast control to maximum Connect a SIGNAL GENERATOR Connect as shown Produce short clip lead between TP806 and 807 of36 875MHz signal BIAS SUPPLY Apply t7 5 volts bias to TP204 RF MODULATOR Connect as shown OUT PUT PAD Connect as shown VTVM Check to bias voltage STEP ADJUSTMENT SWEEP MARKER GENERATOR GENERATOR COMPONENT PROCEDURE 1 Set the Colour control to centre of its range 2 Apply...

Page 16: ... Connect Oscilloscope to TP805 Vertical range O SV cm 2 Adjust 4 43MHz T803 Adjust T803 for maximum deflection on scope CW Trans Output level 1 l 0 3V p p COLOUR SYNC ALIGNMENT STEP ADJUSTMENT COMPONENT I PROCEDURE 1 Connect a short clip lead between TP806 and TP807 Turn the Colour Killer control to fully counter cloc wise position 2 Adjust APC Trans T802 Adjust APC Trans T802 to obtain colour syn...

Page 17: ...rans T804 Adjust T804 to the response curve B shown in Figure 14 4 Remove Oscilloscope to TP804 SOUNDTRAPALIGNMENT STEP I ADJUSTMENT COMPONENT PROCEDURE 1 Connect Oscilloscope to TP802 Fine tune until sound appears in the chroma signal 2 Adjust 5 5MHz Sound Trap trans T207 Adjust the 5 5MHz sound trap T207 for minimum sound in the chroma signal CORRECT IN CORRECT Response A CORRECT IN CORRECT Resp...

Page 18: ...ever should not be subjected to overload even for a moment Be sure to switch off the power source when removing or soldering leads or measuring resistance 2 Essential Conditions in Checking Transistors The test and replacement of power transistors must be carried out in such a way that the transistor is kept in its heat sink Valve checking is simple but with tran sistors testing is complicated by ...

Page 19: ...t iron core short etc CHECKING OF TRANSISTORS BY OHMMETER Transistors can be checked by measuring the forward backward resistances between collector and base emitter and base and and Since the function of a diode exists between emitter and base collector and base low and high resistances are indicated by polarity when measured with a test meter The former is the for ward resistance and the latter ...

Page 20: ...R COLORLESS EXAMPLE A RED B VIOLET 27 x lo3 C ORANGE 27 OOOa D CX LD 27Kfi2 5 CAPACITOR I I I A CAPACITY B 0 TOLERANCE WITHSTAND VOLTAGE A B EXAMPLE 1RO 1PF G 2 1B 12v 3A 1KV 100 1OPF J 5 1E 25V 3D 2KV 101 1OOPF K 10 1H 5ov 3F 3 15KV 102 1OOOPF M 20 2E 250V 3G 4KV 103 O OljfF P 100 O 2F 315v 2u 104 O lpF S 150 O 2H 5oov Except for the T 200 O WITH UNDER LINE above the indica tion methode 2s Z 80 2...

Page 21: ...2 L w w l i i I I Q704 I i 0701 0702 y B I i I Picture Tube i 0 c J Yes L w B J t Firstly turn off the power switch and about 15 seconds thereafter turn on the power switch At this moment is horizontal oscillation sound heard I I When SCR 0613 is disconnected and the power switch is turned on i 20704 T701 Yes Q602 Q603 I Q606 I r R747 I I L I mm A w w I SCR 0613 p w I I Check Bz line i L I J i 061...

Page 22: ...es 1 noise appear on the screen Yes t Make the pin 9 of I201 be grounded and check for the voltage of TP205 Normal 3 6V fl Check for the voltage at B4 I terminal 1 No Check for the voltage at the base collector and emitter of Q207 Normal 9 Abnormal 9 F l I r i r i I 1201 I I ZD201 I I Q203 I I Q204 i L B B J I R463 L e B A 22 ...

Page 23: ...I I D301 I T301 T302 I I 1301 La A Checked Circuits l Sound Circuit l Audio Output Circuit I Hum is created When the pin 6 of 1301 is grounded does sound come out I I No t Check for the voltage at the pin 5 of 1301 I C306 I c305 I I R304 I I J c Normal 12 5V VW 0208 7 0209 i I I D201 1 I I I Apply main ripple to the 1 pin 1 of 1302 via 0 1 S capacitor and 47K ohm resistor r L 7 I 1302 i Speaker I ...

Page 24: ... of 09 Check for the voltage at the collector base and emitter of Q401 Normal Abnormal t r I Q402 i t r I Q401 f L w 4 L J synchronization Is it impossible even if V HOLD R506 J r I I Q501 i r Q502 t c503 I I a Only horizontal synchronization I I I I Is it impossible aven if H HOLD R618 and H FREQ R617 controls are adjusted 1 Check Q613 I D601 I 0602 I t Q601 IL C601 _I e w 1 24 ...

Page 25: ...19 I R520a R52 I R522 R523 I L l I I I Check Q503 base voltage Normal 2V 1 C506 I I I I I 1 a I 1 I i Deflection coil L I T501 I I I L501 I 1 I I J r I I r f 7 I 0503 I I c507 I I c509 I I I I I I J I DEFECTIVE VERTICAL AMPLITUDE AND VERTICAL LINEARITY I I Adjust the controls W LIN V SIZE 4 9 T T o p con pression l 7 e m _ _ I w s I Check for Vertical oscillator driver and output circuit L I I 25 ...

Page 26: ...rast control to maximum 4 Check aerial cable No colour I When the junction bet TP806 and TP807 is shorted does colour No colour P i 1801 I I 51 Yes 1 Is there chroma signal at TP802 I I Check for the voltage at the collector emitter and base of 0801 When the emitter collector junction of Q802 is shorted does colour 1 I I J r 1 I I 1802 Q802 I a t i 26 ...

Page 27: ...2 I I I L809 I l 808 f L807 f Is04 t 1 i 0a w M Is the white balance properly adjusted No r 1 x djust the white balance L m M J f r The picture coloured red The picture coloured green The picture coloured blue or cyan or magenta or yellow I 7 A L 7 r QlOOl c J c 1 I Q1003 L A a J Checked Circuits l 1801 and its Adjacent Circuit I t m I 1801 Cl306 I I X801 C808 f T802 C807 I L803 I I C811 I I C812 ...

Page 28: ...PRINTED WIRING BOARD ASSEMBLIES I Figure 18 PWB A Component Side 28 ...

Page 29: ...Figure 19 PWBA Wiring Side 29 ...

Page 30: ...Figure 20 FWB B Component Side 30 ...

Page 31: ...Figure 21 PWB B Wiring Side 31 ...

Page 32: ... PWBF0491CE ...

Page 33: ...Figure 26 PWB E Component Side Figure 27 PWB E Wiring Side 33 ...

Page 34: ...Figure 28 PWM A Component Side Figure 29 PWM A Wiring Side 34 ...

Page 35: ... 0 TP206 T206 c l 0 0 0207 T205 l a 0 0206 0 TP205 0203 0 6 o Oo205 0204 TC c 1 TB l 1 TN 11 0 0 0 0 c l 0 Q 0201 R 06 RF AGC T203 T202 T201 EL SELECTOR BUT TON ESE7 FINE TUNING KNOB DUNTK0487 r L BAND SELEGTaS SWITCH R454 R436 SUB CONTRAST PEDESTAL LEVEL SET Figure 30 1 35 ...

Page 36: ...4YOUT R70 0 C70GfA A 0702 R70l R702 OD POR701 DUNT KOS25 TP70l R6lB R617 R627 1 R5b RSl7 RS06 I I DUNTKOSP 7 RIOIS co G DRIVE RI016 B DRIVE G S I ssis Layout 36 ...

Page 37: ...BLO TOUCH BUTTON I CHANNEL INDECATOR I SENSOR PWB A SP3Ol SPEAKER PIglO IISA S A M P Irt VIDEO 2nd VIDEO CORRECTION TlON REGULATOR Ii AFC SIDE PIN AMP ...

Page 38: ...C ADJ u T 1 I PHASE DL PHASE OR DC I V I D E O PEDESTAL BRIGHTN ESS AMP 5 th V I D E O A M P 06 407 Q409 0410 1 041 I 08 L w 373 372 O L 2SC373 2SA509 0 4 th VIDE AMP BLANKING A MP l5V 25V REGULATOI _ 0404 C 412 25v 80 2SC 372 0 1 b o Q40S Q413 ONTRAST 2SA495fY t A 2SD235 Y PWB E c 0701 0702 240V B l o c k D i a g r a m 38 ...

Page 39: ...esistors are l 4 watt unless othenvise noted 3 All capacitors MFO unless otherwise noted P MMFO Voltage Measurement Conditions 1 Voltaps in parenthesis measured with no Signal 2 Voltay s without parenthesis measured with 1000 N 8 w or colour Signal 9 All the voltages in each point an measunzd with Vacuum Tube Volt Meter Waveform Measurement Conditions 1 Colour bar generator signal of 2 V peak to p...

Page 40: ... I 8 VPP W 1 2 WXJ H I 3 3 4Vpp H 1 4 6 4Vpp U I I 51 WPP t 0 1 ...

Page 41: ...tor Voltage Regulator I 5V 2SC373 Transistor 3rd Video Amplifier 2SC372 Transistor 3rd Video Amplifier 2SC373 Transistor 3rd Video Amplifier 2SC373 Transistor 4th Video Amplifier 0410 0411 Q412 Q413 Q501 Q502 Q503 Q504 Q505 Q506 0507 0601 Q602 0603 Q604 0605 Q606 0607 0609 0610 0613 0701 Q702 Q703 0704 0705 0801 0802 01001 Q1002 Q1003 1101 1102 1201 1202 1301 2SC373 2SA509 01 2SA495 Y 2SD235 Y 2SC...

Page 42: ...11 E SCR Protector D103 RH PX0007CEZZ LED Channel Indicator DlOOl RH DXOO55CEZZ Diode Protector D104 RH PX0007CEZZ LED Channel Indicator POR701 RMPTPOO18CEZZ Positive Coefficient 0105 RH PX0007CEZZ LED Channel Indicator Thermistor Degaussing D106 RH PX0007CEZZ LED Channel Indicator X801 RCRSAOOl 1 CEZZ Crystal 4 43MHz D107 RH PX0007CEZZ LED Channel Indicator D108 RH PX0007CEZZ LED Channel Indicato...

Page 43: ...R824 R839 R1007 R1008 R1009 R1015 R1016 R1032 Cl16 c209 c315 c317 c319 c419 c510 c513 c514 C516 C518 c519 C520 C611 C612 C614 C615 C616 C620 C623 C624 C627 C628 C629 C630 C633 C632 C633 C634 C635 C638 C639 PART NO DESCRIPTION RVR B4226CEZZ RVR B4226CEZZ RVRB4375CEZZ RVR B4369CEZZ RVR B4226CEZZ RVR B4153CEZZ RVR B4153CEZZ RVR B1072CEZZ RVR B4149CEZZ R R B41 93CEZZ RVR B4153CEZZ RVR B1076CEZZ RVR B4...

Page 44: ...l23J Oxide Metal Coating R750 VRN RT3AAlROK Metal Coating 1 ohm 1W 12K ohm 2W 5 10 R209 VRS PU3DB331 J Oxide Metal Coating RI017 VRS PU3DB123J Oxide Metal Coating 330 ohm 2W 5 12K ohm 2W 5 R245 VRS PU3AB821 J Oxide Metal Coating RI018 VRS PU2DBl23J Oxide Metal Coating 820 ohm IW 5 12K ohm 2W 5 R246 VRS PT3AB392J Oxide Metal Coating R1019 VRS PU2DBl23J Oxide Metal Coating 3 9K ohm 1W 5 12K ohm 2W 5...

Page 45: ... Cl621 CEZZ QFS C1021TAZZ QTANN0631 CEO0 QSOCV1419CEZZ QSPGC0008CEZZ QSPGC0005CEZZ QSPG H0004CEZZ QSW S0007CEZZ QSW MO001 VAZZ RR ET OO29C EZZ VSPl91OP 118A VTUVT7 5A3 Touch Button Hinge AC Cord Impedance Converter Fuse 2AT Fuse 2AT Fuse 1 6A Fuse 1 AT Antenna Terminal Socket Picture Tube Spark Gap Spark Gap Spark Gap Service Switch Door Switch High Voltage Rectifier Unit Speaker Tuner 45 ...

Page 46: ...S H A R P 46 ...

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