Emerson Keystone Figure 637 Service Manual Download Page 1

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^Emerson Radio

e/eMcn,

SERVICE MANUAL

MODELS 614-637-644-647-648B

Television Receivers

EMERSON RADIO AND PHONOGRAPH CORPORATION

111 EICHTH AVENUE

NEW Y O R K 11, N. Y,

MODEL 61*

MODEL 637

MODEL 644

MODEL 647

MODEL 648B

Scanned by mbear2k - Jan 20121/17

Summary of Contents for Keystone Figure 637

Page 1: ...n SERVICE MANUAL MODELS 614 637 644 647 648B Television Receivers EMERSON RADIO AND PHONOGRAPH CORPORATION 111 EICHTH AVENUE NEW YORK 11 N Y MODEL 61 MODEL 637 MODEL 644 MODEL 647 MODEL 648B Scanned by mbear2k Jan 20121 17 ...

Page 2: ...t ___________________________ 16 VII Tuner Alignment ________________________________ 17 VIII Deflection Waveform Test Points ______________ 18 4 LIST OF ILLUSTRATIONS 4 Fig DESCRIPTION Page 5 1 1 Front View of Chassis 120098B _________________ 3 1 2 Tube Location Diagram _________________________ 4 1 3 Video Audio and Oscillator Frequencies______ 4 5 3 1 Front Panel Controls _____________________...

Page 3: ...ng a type 10BP4 picture tube Model 644 is housed in a table model cabinet Model 647 uses a consolette type of cabinet 2 SPECIFICATIONS a TUBE COMPLEMENTS Table 1 NOTE The tube complements of both chassis are alike except for the kinescope Chassis 120113B uses type 12LP4 kinescope some chassis may be equipped with a type 12QP4 SYMBOL TUBE TYPE FUNCTION V I 6AG5 First video i f amplifier V2 1 6AG5 S...

Page 4: ...nd all adjustments properly set Present models are equipped with internal antennas and me chanical deflection centering Initial production mod els do not include the built in antenna and make use of combined electrical and mechanical centering 2 ANTENNA INSTALLATION Chassis 120110B and 120113B are designed to operate with high sensi tivity and will provide excellent reception in many areas with th...

Page 5: ... these adjustments 3 Adjust the ion trap magnet by moving slowly forward or backward while rotating slightly around the neck of the kinescope to obtain maximum picture brightness Reduce the BRIGHTNESS control setting until the pat tern is at approximately normal brilliancy Ad just the FOCUS control at the rear of the chassis for maximum sharpness of raster lines Then readjust the ion trap for maxi...

Page 6: ...Figure 3 4 Test Pattern Excessive Contrast Figure 3 5 Test Pattern Excessive Brightness Figure 3 8 Test Pattern Focus Misadjusted Figure 3 7 Test Pattern Horizontal Hold Misadjusted Figure 3 9 Test Pattern Weak Signal Figure 3 6 Test Pattern Vertical Hold Misadjusted 6 Scanned by mbear2k Jan 20121 17 ...

Page 7: ...ELECTOR control to the proper channel number 2 Readjust the TUNING control if necessary to obtain best picture quality 3 Readjust the CONTRAST control slowly un til the desired picture quality is obtained 4 Readjust VOLUME to suitable level 5 Readjust BRIGHTNESS control for desired brilliancy c CHECKING OPERATION The use of auto matic frequency control in the sync circuits of the receiver makes re...

Page 8: ...tapped primary L I of the r f coil is designed to match a balanced 300 ohm line The secondary L2 is tuned by the input capacity of V28 in series with the parallel combination of trimmer A 14 and a 5 mmf condenser The output of V28 is coupled to V27A by L3 which is tuned by trimmer A15 and the output capacity of the tube A 10K resistor loads L3 to provide the required band pass The input capacity o...

Page 9: ... os cillator signal will cause the input voltage applied to one diode section of V12 to differ from that of the other and result in a d c bias voltage on the grid of the horizontal control tuoe V Ilb This bias voltage will be proportional to the phase dis placement between the incoming sync pulses and the horizontal oscillator voltage and of a polarity determined by the lead or lag of the oscillat...

Page 10: ...bqth directions by means of a second lever which is adjustable from the rear of the cabinet without removing the back This enables precise mechani cal control of centering Section 5 MAINTENANCE AND ALIGNMENT 1 GENERAL All adjustments must be made only by qualified service technicians Unsatisfactory oper ation should be analyzed and circuits checked syste matically to locate and correct sources of ...

Page 11: ...y the vernier adjust ment focus coil lever is required unless the kinescope has been replaced The wobble plate lever has been initially positioned at the factory and usually will not require readjust ment c ION TRA P Adjust the position of the ion trap as outlined in Section II 5 ELECTRICAL DEFLECTION ADJUSTMENTS The electrical adjustment controls are located at the rear of the chassis For access ...

Page 12: ...librated signal generator or a heterodyne frequency meter with crystal calibrator 2 Output of at least 0 1 volt with an attenuator for adjustment of output GENERATOR FREQUENCIES Table IV d e 4 V V 120 USE CARBON RESISTORS ONLY Figure 5 5 Generator Matching Network VACUUM TUBE VO LTM ETER 1 A diode probe for high frequency measure ments is desirable 2 High input impedance with provision for low vol...

Page 13: ...Emerson Radio Figure 5 3 Scheme Scanned by mbear2k Jan 20121 17 ...

Page 14: ...Emerson Radio iOUNO D ISC itic Jbiagram Chassis 120110B 14 Scanned by mbear2k Jan 20121 17 ...

Page 15: ... 450 KC sweep Marker 4 5 MC Replace v t v m with scope con nected through 10K resistor to junction of R44 and C31 T6 Bottom Position 4 5 MC marker at center of S curve by adjusting secondary bottom 150 KC 4 5 MC 4 99 99 99 T6 Top Peak primary for maxi mum amplitude and linearity Repeat step 3 I5 0 K C b VIDEO I F ALIGNMENT 1 Retain the control settings used for audio i f alignment 2 Connect a 3 vo...

Page 16: ...top to position 22 8 MC marker adjust T2 trap bottom to position 21 25 MC marker 5 9 9 Connect AGC bias battery as indicated above Sweep 23 5 MC 10 MC sweep Markers 25 75 MC and 22 25 MC Connect scope through 10K re sistor to junction of L l R16 and Cl 6 Low side to chassis T2 T3 Adjust T2 top and T3 to give overall response shown T2 top adjusts bandwidth T3 positions video carrier 25 75 MC depend...

Page 17: ...s are shown as bottom v ews Measured values are from socket pin to B unless otherwise stated 5 Readings made with antenna disconnected no signal applied and controls at normal 6 Readings marked are measured to ground 9 DEFLECTION CIRCUIT WAVE FORMS See figure 5 11 The sweep voltages produced in the horizontal and vertical sweep circuits may be used in locating defects in the deflection section of ...

Page 18: ... V 36 6 Pin 1 BH 8 9 BV 11 3 First Sync Amp V 15B Pin 6 CH 11 4 CV 18 5 Second Sync Amp V 6B Pin 6 DH 77 4 D V 117 Hor Phase Inv V llA Pin 2 EH 19 0 EV 40 2 Phase Det V 12 Pin 5 GH 8 7 G V 9 7 Pin 7 H H 6 0 H V 9 2 Hor Control V llB Pin 5 IH 14 5 Hor Osc V 13 Pin 5 JH 55 4 Pin 1 KH 53 5 Vert Osc V 14 Pin 4 LV 178 Pin 2 M V 100 Vert Output V 16 Pins 3 4 N V 303 18 Scanned by mbear2k Jan 20121 17 ...

Page 19: ...fd A terminal of C 21 on the terminal strip near V 6 and V 15 Rewired R 27 be tween pin 6 of V 5 6AU6 and the empty lug on the terminal strip adjacent to the power transformer added a wire from this point to the junction of R 52 470 000 ohms and the green lead from the fuse holder 5 Opened junction of blue lead from C 21 with R 26 3900 ohms on the terminal strip near V 6 and V 15 6 Rewired R 26 to...

Page 20: ... Lug 8 of V l socket to lug 7 of V 14 socket f Lug 7 of V 14 socket to lug 2 of V 16 socket CODE MARKING TRIANGLE 4A Same as for code marking Triangle 4 but includes built in internal antenna and following revisions 1 Replaced jumper lead between pin 7 cathode of V 9 and terminal strip with r f choke L 13 part no 705002 k 2 Inserted C 17 1500 mmf between pin 7 of V 8 and chassis CODE MARKING TRIAN...

Page 21: ...LTAGES MEASURED TO CHASSIS WITH ALL FRONT CONTROLS COUNTER CLOCKWISE AND REAR CONTROLS NORMAL NO SIGNAL INPUT Figure 5 13 Bottom View of Chassis 12 CABINET PARTS LIST Models 614 637 644 647 ITEM PART NO MODEL 614 MODEL 637 MODEL 644 MODEL 647 Cabinet 140279 140276 140320 140325 Cabinet back 560097 56010S 560109 560115 Safety glass 635023 635020 520119 520119 Mask 410805 410859 410859 Mask extrusio...

Page 22: ...f 450V R 7 340732 10 000 ohm y2w 1 0 17 0 4 1 Pt of 0 2 1 40 mf 450V R 8 340652 4 700 ohm y2w 1 0 17 0 4 2 Pt of 0 2 9 40 mf 450V R 9 340132 33 ohm y2w 1 0 17 0 4 3 928006 1 500 mmf 400V 30 R 10 340492 1 000 ohm y2w 1 0 17 0 4 4 923067 1 mf 200V 30 R ll 340492 1 000 ohm y2w l0 o 17 0 4 5 923064 1 mf 400V 30 R 12 340632 3 900 ohm w id o 17 0 4 6 910028 220 mmf 1 0 30 R 13 340292 150 ohm w 1 0 17 0 ...

Page 23: ...40892 47 000 ohm J w 1 0 17 T 12 730018 Power transformer 30 00 R 77 371132 470 000 ohm lw 1 0 16 R 8 371132 470 000 ohm lw H 10 16 V l 800535 Vacuum tube 6AG5 R 79 331132 470 000 ohm 2w 5 14 V 2 800535 Vacuum tube 6AG5 R 80 390102 20 000 ohm Hor Drive con trol 90 V 3 V 4 800533 800541 Vacuum tube 6AU6 Vacuum tube 6AL5 R 81 340792 18 000 ohm 2W 1 0 14 V 5 800533 Vacuum tube 6AU5 R 82 341132 470 00...

Page 24: ...ON Cabinet Bakelite Mask Knob Off Volume Knob Fine Tuning Knob Contrast and Brightness Knob Selector Connector Plug Speaker Selector Escutcheon Back Twin Conductor Lead 110 Line Cord Plug and Cable Speaker Safety Glass Speaker 6 TUBE COMPLEMENTS CHASSIS 120110 E SYMBOL TUBE TYPE FUNCTION VI 6AG5 First video i f amplifier V2 6AG5 Second video i f amplifier V3 6AU6 Third video i f amplifier V4 6AL5 ...

Page 25: ...Emerson Radio SOUWJ i r AMP SOUND I F L IM IT E R SOUND D a AUDIO Fig 2 Schematic Diagram Chassis 12 25 Scanned by mbear2k Jan 20121 17 ...

Page 26: ...Emerson Radio dio M 26 28 Scanned by mbear2k Jan 20121 17 ...

Page 27: ... 600v F l 808170 Fuse A 250v 1 1 708086 Ion Trap P M double L l 708096 Peaking coil 75 uh L 2 708097 Peaking coil 45uh 1 0 J____________ J L MODEL 648B P SYMBOL PART NO DESCRIPTION L 3 708095 Peaking coil 180 uh L 4 708095 Peaking coil 180 uh L 5 705009 R F choke 3 0 mh 1 0 L 6 708082 Size coil L 7 708003 Linearity coil L 8 708130 or Deflection yoke vert coils L 9 708130 Deflection yoke horiz coil...

Page 28: ... me R 72 330972 100 000 ohm Carbon T 6 708017 or Discriminator coil 4 5 me y2w 5 T 6 708018 Discriminator coil 4 5 me R 73 330972 100 000 ohm Carbon T 7 734051 Sound output transformer y2w 5 T 8 738008 Horiz oscillator transformer R 74 370652 4 700 ohm Carbon lw 10 T 9 738028 Horiz output transformer R 75 390133 50 000 ohm Horiz Hold T 10 738029 Vert output transformer Control rear T ll 730018 Pow...

Page 29: ...riangle 6 stamped at the rear of chassis 120110B or 120113B includes the change of the vertical sweep generator to the multivibrator type with an auto transformer in the output circuit This revision is indicated in the schematic diagram figure 3 All previous modifications listed in the present service manual are included 3 MECHANICAL CENTERING Use of mechanical centering controlled by the wobble p...

Page 30: ...o the original circuit SYMBOL n PART No DESCRIPTION SYMBOL PART No DESCRIPTION C 32 928006 1500 mmf 400v R 94 340972 100 000 ohm 1 0 C 37 923088 002 mf 600v R 95 390132 100 000 ohm Vert Hold control C 68 923088 002 mf 600v R 96 340872 39 000 ohm 1 2wi 1 0 C 69 923079 001 mf 600v R 97 340572 2 200 ohm w 1 0 C 70 923079 001 mf 600v R 98 331392 5 6 megohn w 1 0 C 71 922014 1 mf 200v R 99 390138 3 meg...

Page 31: ...SOUND I F AMP SOUND f L IM IT E R SOU a A 0 i tig 3 Schematic D Scanned by mbear2k Jan 20121 17 ...

Page 32: ... a ram Chassis 120113C Scanned by mbear2k Jan 20121 17 ...

Page 33: ...ew series and pertains to the Model 637 chassis model 110 Chassis bearing the code Triangle 1 have the following revisions incorporated Circuit Revisions to Correct Picture FLICKER or BOUNCE 1 2 3 U 5 6 Remove red lead from the B plus 125 volt point on terminal strip near Uth I F and from Pin 6 of the 6AU6 V 5 Remove red lead from the of the 6AU6 V 5 terminal of C U2 and from Pin 6 Insert a wire b...

Page 34: ... 1 Transfer yellow wire from dummy lug strip near vertical blocking transformer junction of R63 R64 R65 R93 and R97 to junction of C51 C61 and C68 2 Remove yellow wire from the same dummy lug strip junotion of C51 C68 C61 and eleotrolytlo oan 3 Add new yellow wire between same dummy lug at junction of R63 R64 R65 R93 R97 to eleotrolytlo oan C29 near V 4 6A15 socket 4 Transfer lead of C68 002 mfd 6...

Page 35: ... this resistor to the same lug of terminal strip near C21 in step 2 4 From this mm empty lug run a jumper lead approximately 16 long to another empty lug on the terminal strip near the 6W4 On this new terminal lug connect a 10K 1 watt resistor to the junction of the 3300 ohm 1 watt R 102 and the resistor 7500 ohm R86 Boostered B plus point 6 Replace 047 C 19 kinesoope coupling with a 01 mf condens...

Page 36: ...unction of U70K ohm resistor and green wire from fuse on terminal board under horizontal blocking oscillator transformer 5 Put 16 jumper wire from terminal board 3ide of 10K resistor as in 1 and junction of R 36 damper resistor and lead to Pin 3 of 6wU damper tube 6 Replace C 19 0U7 mf with a 01 m f condenser U00 volt NOTE Materials needed for above revisions One 10K watt resistor one 01 mf conden...

Page 37: ...r 71 U Resistor R60 has been transferred from the B plus point on terminal strip near Tube 71 to the B minus point of the terminal strip near Tube 71iu 5 Resistor R6U has been transferred from the B minus point on terminal stip near VlU to the junction of R60 and R90 on the terainal strip near the 2nd I F The suffix letter C added to the Triangle 1 code indicates the use of electrolytic condenser ...

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