RCA Victor 648PTK User manual

295
Model 648PV
Walnut or Mahogany
rcaV ict0R
PROJECTION TELEVISION,
AM-FM RADIO, COMRINATION
MODEL 648PTK
Chassis Nos. KCS 24-1, KRS 20-1, KRS 21-1
KRK 1-1, RK-121A and RS-123A
PROJECTION TELEVISION
AM-FM RADIO PHONOGRAPH
COMRINATION
MODEL 848P¥ '
Chassis No. KCS 24A-I, KRS 20-1, KRS 2IA-I
KRK-iA, RK-I2IA and RS-I23B
Mfr. No. 274
Service Data
- 1947 No. 12 -
- 1948 No. T4 -
RADIO CORPORATION Of AMERICA
RCA VICTOR DIVISION
CAMDEN, N. J., U. S. A.
GENERAL DESCRIPTION
Model 648PTK is a forty-eight tube Projection Television,
AM-FM Radio, console combination. The television receiver em¬
ploys four chassis with a total of thirty-five tubes and a five-
inch projection kinescope. A Reflective Optical System pro¬
vides a 15" x 20" picture on the screen.
Features of the television unit are full thirteen channel cov¬
erage; FM sound system; improved picture brilliance; picture
A-G-C; A-F-C horizontal hold; stabilized vertical hold; two
stages of video amplification; noise saturation circuits; three-
stage sync separator and clipper; four me band width for pic¬
ture channel and reduced hazard high voltage supply.
The radio receiver employs an eight-tube tuner unit and a
four-tube audio-amplifier, power-supply unit.
The radio chassis is provided with a Phono input jack to
permit the use of an external record player.
Model 648PV is .a forty-eight tube Projection Television,
AM-FM Radio, Phonograpn, console combination. The television
receiver employs four chassis with a total of thirty-five tubes
and a five-inch projection kinescope. A Reflective Optical
System provides a 15" x 20" picture on the screen.
Features of the television unit are full thirteen channel cov¬
erage; FM sound system; improved picture brilliance; picture
A-G-C; A-F-C horizontal hold; stabilized vertical hold; two
stages of video amplification; noise saturation circuits; three-
stage sync separator and clipper; four me band width for pic¬
ture channel and reduced hazard high voltage supply.
The radio receiver employs an eight-tube tuner unit and a
four-tube audio-amplifier, power-supply unit.
An automatic record changer of the "slicer” type is em¬
ployed and features a crystal pickup with the "Silent Sap¬
phire” stylus.
ELECTRICAL AND MECHANICAL SPECIFICATIONS
TELEVISION R-F FREQUENCY RANGES
Television
Picture
Sound
Tel. Rec.
Channel
Channel
Carrier
Carrier R-F Osc.
Number Freq. Me.
Freq. Me. Freq. Me. Freq. Me.
1.
.44-50.
.45.25.
.49.75. .71
2 .
.54-60.
. 55.25 . .59.75. .81
3.
.60-66.
.61.25. .65.75.
.87
4..
......66-72.
.67.25.
.71.75 . .§3
5 .
.76-82.
.......77.25. .81.75.
.103
6.
.82-88.
.83.25.
.87.75....... .. . 1 09
7.........
....174-180.
.175.25.
.179.75....... .201
8.
....180-186.
.181.25.
.185.75..:....
.........307
9 .
....186-192.
.187.25.
.191.75.
..213
10 .
....192-198.
.193.25.
.197.75. .219
11.
....198-204.
.199.25. .203.75.
.225
12 .
....204-210.
.205.25.
.209.75. .231
13 .
....210-216.
.211.25. .215.75.
.237
TELEVISION FINE TUNING RANGE
Plus and minus approximately 800 kc on channel 1, and
plus and minus approximately 1.9 me on channel 13.
PICTURE SIZE .....................................15" x 20"
RADIO TUNING RANGE
Broadcast ..... 540-1,600 kc
Short Wave . 9.2-18 me
Frequency Modulation . 88-108 me
Intermediate Frequency—AM . 455 kc
Intermediate Frequency—FM . 10.7 me
RECEIVER ANTENNA INPUT IMPEDANCE..300 ohms balanced
Specifications continued on page 3

296
648PTE. 8 4 SPY TABLE OF CONTENTS
Page
Alignment Procedure (Television)
Detailed ......... 22
Table ......... 28
Alignment Procedure (Radio) . 44
Antenna ............. 11
Circuit Description (Television) .... 12
Circuit Description (Radio) .. 33
Drawings (Major)
Television
Adjustment Location (Alignment) . 30
Adjustment Location (Installation) . 9
R-F, I-F Chassis Views . 20
Horizontal Deflection Chassis View .. 21
Chassis Wiring Diagrams . 56
Circuit Schematic .59-63
R-F Unit Wiring Diagram .57-61
Radio
Adjustment Location . 45
Chassis Wiring Diagram .46-47
Circuit Schematic .48-49
Pag®
General Description .. 1
Interference ............ jj
Installation Instructions ....._ §
Operating Instructions .......... 4
Photographs
Cabinet . j
Test Pattern . «
Waveform . gg
Precautions
Kinescope Handling . 2
Ventilation . H
Reflections ...
Replacement Parts . 05
Service Suggestions .. 32
Specifications (Elec. & Mech.) . 1
Test Equipment . 22
Tube Complement . g
Voltage Chart (Television) . 42
Voltage Chart (Radio) . 5 q
Warning (High Voltage) . 2
HIGH VOLTAGE WARMING
OPERATION OF THIS RECEIVER OUTSIDE THE CABINET OR WITH THE COVERS REMOVED,
INVOLVES A SHOCK HAZARD FROM THE RECEIVER POWER SUPPLIES. WORK ON THE RE¬
CEIVER SHOULD NOT BE ATTEMPTED BY ANYONE WHO IS NOT THOROUGHLY FAMILIAH
WITH THE PRECAUTIONS NECESSARY WHEN WORKING ON HIGH VOLTAGE EQUIPMENT.
DO NOT OPERATE THE TELEVISION RECEIVER WITH THE HIGH VOLTAGE COMPARTMENT
SHIELD REMOVED.
KINESCOPE HANDLING PRECAUTIONS
DO NOT OPEN THE KINESCOPE SHIPPING CARTON, INSTALL, REMOVE OR HANDLE THE KINE¬
SCOPE IN ANY MANNER UNLESS SHATTERPROOF GOGGLES AND HEAVY GLOVES ARE
WORN. PEOPLE NOT SO EQUIPPED SHOULD BE KEPT AWAY WHILE HANDLING KINE¬
SCOPES. KEEP THE KINESCOPE AWAY FROM THE BODY WHILE HANDLING.
The kinescope bulb encloses a high vacuum and, due to its large surface area, is subjected to considerable air pressure.
For these reasons, kinescopes must be handled with more car© than ordinary receiving tubes.
Th® large end of the kinescope bulb—particularly that part at the rim of the viewing surface—must not be struck, scratched
or subjected to more than moderate pressure at any time. In installation, if the tube sticks or fails to slip smoothly into Its
socket, or deflecting yoke, investigate and remove th© cause of the trouble. Do not force the tube. Refer to the receiver
Installation Instructions section for detailed Instructions on kinescope installation. All RCA kinescopes are shipped in special
cartons and should be left in the cartons until ready for installation in the receiver.. Keep the carton for possible future use.

297
ELECTRICAL AMD MECHANICAL
POWER SUPPLY BATING
Television Operation . 115 volts, 60 cvcles, 530 watts
Radio Operation . 115 volts, 60 cycles, 145 watts
Phonograph Operation . 115 volts, 60 cycles, 165 watts
AUDIO POWER OUTPUT RATING
Undistorted Power Output .... iq watts
Maximum Power Output ....." ’ ’’ n watts
.CHASSIS DESIGNATIONS 648PTK
Television R-F, I-F Chassis .KCS24-1
Horizontal Deflection Chassis . KRS20-1
Television Power Supply Chassis .KRS21-1
Optical Barrel . KRK1-1
Radio Chassis .RK121A
Audio Amplifier . RS123A
Record Player .
648PV
KCS24A-1
....KRS20-1
KRS21A-1
.. KRK-IA
. RK121-A
... RS123B
. RP176
LOUDSPEAKER (92567-2)
Type .
Voice Coil Impedance .
WEIGHT
Chassis with Tubes in Cabinet
Shipping Weight .
12-inch Electrodynamic
2.2 ohms at 400 cycles
648PTK 648PV
■ • 295 lbs. 323 lbs.
360 lbs . 407 lbs.
DIMENSIONS (inches) Width Height
Cabinet (outside) . 648PTK. 36 % 471/2
Cabinet (outside) . 648PV. 48 39 V 4
Depth
22 %
251/2
TELEVISION CHASSIS DATA
PICTURE I-F FREQUENCIES
Picture Carrier Frequency . 25.75 me
Adjacent Channel Sound Trap . 27.25 me
Accompanying Sound Traps . 21.25 me
Adjacent Channel Picture Carrier Trap . 19.75 me
SOUND I-F FREQUENCIES
Sound Carrier Frequency . 21.25 me
Sound Discriminator Band Width (between peaks) . 350 kc
VIDEO RESPONSE . To 4 me
FOCUS . Electrostatic
SWEEP DEFLECTION ... Magnetic
SCANNING . Interlaced, 525 line
HORIZONTAL SCANNING FREQUENCY . 15,750 cps
VERTICAL SCANNING FREQUENCY . 60 cps
FRAME FREQUENCY (Picture Repetition Rate) . 30 cps
NON-OPERATING CONTROLS (not including r-f and i-f adjust¬
ments)
SPECIFICATIONS (Continued) 648PTK , 648PV
P.CA TUBE COMPLEMENT
KCS24-1, KCS24A-1 R-F, I-F CHASSIS
Tube Used Function
( 1 ) RCA- 6 J 6 ..... R-F Amplifier
(2) RCA- 6 J 6 . R-F Oscillator
(3) RCA- 6 J 6 ..... Converter
(4) RCA- 6 BA 6 . 1 s t Sound I-F Amplifier
(5; RCA- 6 BA 6 . 2nd Sound I-F Amplifier
( 6 ) RCA- 6 AU 6 .. 3rd Sound I-F Amplifier
(') RCA-6AL5 ... Sound Discriminator
( 8 ) RCA- 6 AT 6 ... A-G-C Amplifier
(9) RCA-6AL5 . A-G-C Diode and D-C Restorer
( 1 0 ) RCA-6AG5 . 1 st Picture I-F Amplifier
ul) RCA-6AG5 . 2nd Picture I-F Amplifier
(.12) RCA-6AG5 . 3rd Picture I-F Amplifier
(13) RCA-6AG5 . 4th Picture I-F Amplifier
(14) RCA-6AL5 . Picture 2nd .Detector and A-G-C Detector
(15) RCA- 6 AU 6 . 1 s t Video Amplifier
(16) RCA- 6 V 6 GT . 2nd Video Amplifier
(17) RCA-6SK7 . 1 st Sync Amplifier
(18) RCA-6SH7 . 2nd Sync Amplifier
(19) RCA-6J5 . 3 rd Sync Amplifier
(20) RCA-6J5 . Vertical Sweep Oscillator and Discharge
(21) RCA- 6 K 6 GT . Vertical Sweep Output
KRS20-1 HORIZONTAL DEFLECTION CHASSIS
Tube Used Function
(1) RCA- 6 H 6 . Horizontal Sync Discriminator
( 2 ) RCA- 6 K 6 GT . Horizontal Sweep Oscillator
(3) RCA-6J5 . Horizontal Discharge
(4) RCA-6AC7 . Horizontal Sweep Oscillator Control
(5) RCA- 6 BG 6 G . Horizontal Sweep Output (2 tubes)
( 6 ) RCA-5V4G . Horizontal Damper
(7) RCA-6AS7G . Horizontal Damper
( 8 ) RCA-1B3-GT/8016 . High Voltage Rectifier (3 tubes)
(9) RCA-5TP4 .... Projection Kinescope
KRS 21-1 , KRS 21 A -1 TELEVISION POWER SUPPLY CHASSIS
Tube Used Function
(1) RCA-5U4G . Rectifier (3 tubes)
Horizontal Centering .. Horizontal Deflection chassis adjustment
Vertical Centering ... R-F, I-F chassis rear adjustment
.... R-F, I-F chassis rear adjustment
Vertical Linearity . R-F, I-F chassis rear adjustment
Width .... Horizontal Deflection chassis screwdriver adjustment
Horizontal Linearity ....Horizontal Deflection chassis adjustment
Horizontal Drive . Horizontal Deflection chassis adjustment
Horizontal Oscillator Frequency
Horizontal Deflection chassis adjustment
Horizontal Oscillator Phase
Horizontal Deflection chassis adjustment
Locus (Electrical) .. Horizontal Deflection chassis rear adjustment
Focus (Mechanical) . Optical Barrel adjustment
Deflection Coil . Optical Barrel adjustment
Video Peaking Switch . R-F, I-F chassis rear switch
Horizontal Optical Centering . Optical Barrel adjustment
Lateral Optical Centering ... Optical Barrel adjustment
RK121A RADIO CHASSIS
Tube Used Function
(1) RCA- 6 BA 6 ..... R-F Amplifier
\2) PlCA- 6 BE 6 . Oscillator
(3) RCA- 6 BA 6 . Mixer
(4) RCA- 6 BA 6 . 1st I-F Amplifier
(5) RCA- 6 AU 6 . 2nd I-F and Phono Amplifier
( 6 ; RCA- 6 AU 6 . Driver
(7) RCA-6AL5 . Ratio Detector
( 8 ) RCA- 6 AT 6 . AM Detector, AVC and Audio Amplifier
RS123A, RS123B AUDIO AMPLIFIER
Tube Used Function
(1) RCA-5U4G . Recti{ier
(2) RCA-6J5 . p hase i nverte r
(3) R 0 A- 6 F 6 G . Power Output (2 tubes)
3

298
648PTI, 848PV
RECEIVER OPERATING INSTRUCTIONS
TELEVISION OPERATION
The following adjustments are necessary when turning the
receiver on lor the first time.
1. Turn the radio FUNCTION switch to Tel.
2. Turn the receiver "ON" and advance the sound VOL¬
UME control to approximately mid-position.
3. Set the STATION SELECTOR to the desired channel.
4. Turn the PICTURE control fully counter-clockwise.
5. Turn the BRIGHTNESS control clockwise, until a glow ap¬
pears on the scieen, then counter-clockwise until the glow just
disappears.
6. Turn the PICTURE control clockwise until a glow or
pattern appears on the screen.
7. Adjust the FINE TUNING control for best sound fidelity
and sound VOLUME for suitable volume.
8. Adjust the VERTICAL hold control until the pattern stops
vertical measurement.
9. Adjust the HORIZONTAL hold control until a picture is
obtained and centered.
10. Adjust the PICTURE control for suitable picture con¬
trast.
11. After the receiver has been on for some time, it may be
necessary to readjust the FINE TUNING control slightly for
improved sound fidelity.
12. In switching from one station to another, it may be
necessary to repeat steps number 7 and 10.
13. When the set is turned on again after an idle period, it
should not be necessary to repeat the adjustments if the posi¬
tions of the controls have not been changed. If any adjustment
is necessary, step number 7 is generally sufficient.
14. If the position of the controls have been changed, it
may be necessary to repeat steps number 2 through 10.
RADIO OPERATION
1. Turn the radio FUNCTION switch to the desired band
(BC, SW or FM).
2. Tune in the desired station with the TUNING control.
PUSH-BUTTON OPERATION
1. Turn the radio FUNCTION switch to the desired band
(BC, SW or FM).
2. Push the appropriate push button to receive the desired
station.
PHONOGRAPH OPERATION
1. Turn the radio FUNCTION switch to the phono position.
2. Slide the changer power switch to "ON.
HORIZONTAL
BRIGHTNESS
STATION
SELECTOR
CHANGER
CONTROL
SWITCH
CHANGER
POWER
SWITCH

299
INSTALLATION INSTRUCTIONS
648PTK, 648PV
MODEL 648PTK
Access to the front tubes in the r-f, i-f chassis may be had
through the front of the cabinet by raising the door stop as
shown in Detail A of Figure 2 and then sliding the right
television door all the''way back. When this check is com¬
pleted, close the door to its normal position and drop the door
stop back in place.
MODEL 648PV
A heat shield is placed over the RSI 2 3. audio amplifier to pre¬
vent the rectifier tube from coming in contact with the optical
barrel dust shield when the cabinet is closed. Care should be
taken to see that this shield is replaced after the cardboard
shipping shields have been removed from the RSI23 amplifier.
To get at the optical barrel adjustments, take out three screws
on each side of the front of the speaker grill and remove the
Remove the shipping material as shown in Figure 2. Make
sure that all tubes are firmly seated in their sockets.
Untie the canvas dust cover for the optical barrel and tie it off
to one side.
Caution: Handle the corrector lens with care. This lens is
made of a plastic material, is soft and can be easily scratched
by improper handling or even by rubbing with a cloth. Do not
use cleaning fluid on the lens as it may be attacked by some
of the chemicals used in such solutions. In short, the lens
should be given the care due any precision optical equipment.
Remove the corrector lens from the top of the optical barrel by
loosening the three screws holding the clamp springs as shown
in Figure 4. Caution: Do not loosen the three screws holding
the corrector lens mounting plate.
Figure 2—Removal
of Shipping Material
MODEL 648PTK
Figure 2—Removal
of Shipping Material
MODEL 648PV

648PTK, 648PV
INSTALLATION INSTRUCTIONS
Although the high voltage filter capacitors of a new receiver
are not likely to be charged, it is a good idea to form the habit
of discharging the optical barrel before making any internal
adjustments. Take a clip lead, fasten the clip end to the bar¬
rel and discharge the unit by making repeated contacts to the
kinescope holder shown in Figure 3.
Clean the back of the screen, the front of the 45° mirror and
the optical barrel spherical mirror by "sweeping" the surface
with a small camel's hair brush. Any dust on the spherical
mirror should be swept into the black center portion where it
can be picked up with a piece of scotch tape. Caution: Do
not touch the silvered portion of the mirrors. The mirrors are
surface silvered and can be damaged by contact with the
moist hand. If the screen or mirrors require cleaning, a solu¬
tion of "Dreft" and water should be employed.
Figure 3—Kinescope Holder
Place a type 202—B—1 test lamp in the kinescope holder
and adjust the ball screws to center the lamp in the holder.
Connect the lamp cord into a 110-volt power outlet and turn
the lamp on. Replace the corrector lens, taking care that the
arrow on the edge of the lens points to the rear of the cabinet.
Rotate the lamp so as to produce a picture on the screen in
the proper aspect. Cover the center hole in the corrector lens
with a piece of black cardboard in order to prevent light from
this source from lowering the resolution. Pull the dust cover
down around the barrel.
Observe the raster on the screen by use of a mirror placed in
front of the set. A chrome-plated photographic ferrotype tin
is excellent for this purpose.
Loosen the optical focus adjustment lock screws and adjust
the optical focus adjustment for the best overall definition on
the screen. The optical system should show at least 900 line
resolution over all the screen. If the system shows less
definition, it will be necessary to make the adjustments under
"Alignment of Optical Barrel."
ALIGNMENT OF OPTICAL BARREL—With the test lamp in
place as described above, turn -the optical focus adjustment
until the vertical and horizontal lines become double. When
the test lamp is properly centered, the lines are parallel. If
the lines are not parallel, the Horizontal or Lateral optical cen¬
tering controls require readjustment.
Lateral Optical Adjustment—If the vertical lines are not par¬
allel, loosen the lateral adjustment set screws and turn the
lateral adjustment until the vertical lines are parallel. Tighten
the adjustment set screws.
Horizontal Optical Adjustment—-If the horizontal lines are not
parallel, loosen the optical horizontal centering lock screws and
turn the optical horizontal centering adjustment until the lines
are parallel. Tighten the adjustment lock screws.
Corrector Lens Centering —Turn the focus adjustment until a
halo appears around the dot in the center of the test lamp.
If the halo is not symmetrical around the dot, loosen the three
corrector lens lock screws and the three corrector lens mount¬
ing clip screws and shift the lens until the halo is symmetrical.
Tighten the lens centering lock screws with the lens in this
position.
Check of Optical Barrel Tilt —Adjust the optical focus control
to and through the focus range. The picture should go through
focus all over at the same time. This does not mean that the
definition will be equal over all the picture, but it should be
the best definition obtainable. If this is not the case, the op¬
tical barrel is not in alignment with the cabinet and requires
adjustment as outlined in the following paragraph.
Optical Barrel Tilt Alignment —Turn the optical focus adjust¬
ment counterclockwise until the picture is out of focus then
clockwise until the picture begins to come in focus. If one side
comes into focus before the rest of the picture, it indicates that
that side of the optical barrel should be raised. Loosen the
lock nuts and turn the inner jack nuts, shown in Figure 4, to
raise that side of the barrel and the other jack nut down to
lower the other side of the barrel, until both sides of the pic¬
ture come into focus at the same time.
If the top of the picture comes into focus first as the optical
focus adjustment is turned clockwise, it indicates that the outer
jack nut (nearest the focus controls) should be adjusted to
lower the back of the optical barrel, until
top and bottom come into focus at the same
time.
When the barrel is properly adjusted, the
entire picture will come into best focus all
over at the same time as the locus control
is rocked through the focus point. At this
point the pattern should be in the center
of the screen. When this condition of align¬
ment is obtained, tighten the lock nuts
being careful not to disturb the adjustments.
If the optical barrel tilt adjustments are
made, it will be necessary to recheck the
adjustments under Horizontal Optical Ad¬
justments and Lateral Optical Adjustments.
Loosen all the kinescope mounting wing
screws equally and just sufficiently to per¬
mit removal of the test lamp.
Figure 4 —Optical Barrel Adjustments
6

INSTALLATION INSTRUCTIONS
S48PTK, 648PV
KINESCOPE HANDLING PRECAUTION— Do not open the kine¬
scope shipping carton, install, remove, or handle the kinescope
in any manner, unless shatterproof goggles and heavy gloves
are worn. People not so equipped should be kept away while
handling the kinescope. Keep the kinescope away from the
body while handling. The shipping carton should be kept for
use in case of future moves.
INSTALLATION OF KINESCOPE—The kinescope second anode
contact is a recessed metal well in the side of the bulb. A
small brass clip (from the carton containing the deflection yoke
and front panel control knobs) must be placed in the kine¬
scope anode contact and the tube inserted in the holder as
shown in Figure 3. The tube must be installed so that the
socket key on the base of the tube is pointed towards the
horizontal deflection chassis. Make sure that the anode clip is
horizontal so that it cannot protrude out of the holder.
Tighten the three ball screws equally to center the tube in
the support. Caution: Do not apply too much pressure to
tightening the ball screws as the tube can be cracked by so
doing.
Wipe the corrector lens clean with a piece of lens tissue and
replace on the barrel. Turn the lens mounting clips in place
and tighten the clip screws.
Turn the deflection yoke so that the slotted end of the bakelite
center tube is up and slide the yoke down over the neck of the
kinescope. Connect the kinescope socket to the base of the
tube.
Slip the yoke cables out through the cable sleeve in the op¬
tical barrel dust cover. The three-prong plug on the un¬
shielded yoke cable should be plugged into the television r-f
i-f chassis as shown in Figure 5. The two-prong plug on the
shielded yoke cable should be plugged into the horizontal de¬
flection chassis. The shield braid extension from this cable
should be grounded to the chassis by means of the screw pro¬
vided for this purpo^p.
Caution—Do not turn the television receiver on with the deflec¬
tion yoke cables disconnected. To do so may cause the de¬
struction of the kinescope screen.
Reconnect the speaker. Check all chassis interconnecting
cables to make sure that all are plugged into the proper
sockets as shown in Figure 5. It is possible to insert the re¬
ceiver antenna and ground plug backwards. The ground wire
should go to the middle connector at the radio chassis as
shown.
Open the kinescope shipping
carton and remove the tube.
Handle this tube by the neck.
Do not cover the envelope of
the tube with fingermarks as
it will produce leakaqe paths
between the high voltage rim
near the screen and the
grounded coating on the neck.
If this portion of the tube has
inadvertently been handled,
wipe it clean with a soft cloth
moistened with ''dry' 1 carbon
tetrachloride, which is obtain¬
able at most drug stores.
Wipe the kinescope screen
clean of all dust or finger
marks with a soft cloth moist¬
ened with the Drackett Co.'s
"Windex" or similar cleaning
□ gent.
MODEL 648PV
Figure 5 —Chassis
Interconnecting Cables

302
INSTALLATION INSTRUCTIONS
848PTK, 648PV
Remove the cover from the horizontal deflection chassis and
take out the strings holding the high voltage filter capacitors
in the clips during shipment. Replace the chassis cover.
The antenna and power connections should now be made.
Turn the power switch to the ''on" position, the function switch
to television, the picture control counterclockwise and the
brightness control clockwise until a glow appears on the
screen.
Adjust the electrical focus control R331 on the horizontal de¬
flection chassis until the raster lines are in sharpest focus as
seen when looking down into the barrel. If necessary, reduce
the brilliance control setting, and readjust the focus control.
Pull the dust cover down around the optical barrel.
Adjust the optical focus adjustment until the raster lines are
in focus on the screen. Turn the deflection yoke until the
raster lines are horizontal on the screen and tighten the yoke
clamp in this position.
Picture Adjustments—It will now be necessary to obtain a test
pattern picture in order to make further adjustments. See step
3 through step 10 of the receiver operating instructions on
page 4.
CHECK OF HORIZONTAL OSCILLATOR ALIGNMENT—The
sync link (see Figure 7) must be in the normal position (2 to
3). Turn the horizontal hold control to the extreme counter¬
clockwise position. The picture should remain in horizontal
sync. Momentarily remove the signal by turning the picture
control fully counterclockwise and then returning it to the op¬
erating position. Normally the picture will pull into sync.
Turn the horizontal hold control to the extreme clockwise po¬
sition. The picture should remain in sync. Momentarily remove
the signal. Again the. picture should normally pull into sync.
If the receiver passes the above checks and the picture is
normal and stable, the horizontal oscillator is properly aligned.
Sk f p "Alignment of Horizontal Oscillator" and proceed with
HEIGHT AND VERTICAL LINEARITY ADJUSTMENTS.
ALIGNMENT OF HORIZONTAL OSCILLATOR—If in the above
check the receiver failed to hold sync with the hold control
at either extreme or failed to pull into sync after momentary
removals of the signal, make the adjustments under "Slight
Retouching Adjustments." If, after making these retouching
adjustments, the receiver fails to pass the above checks or
if the horizontal oscillator is completely out of adjustment,
then make the adjustments under "Complete Realignment."
Slight Retouching Adjustments—Tune in a Television Station
and adjust the fine tuning control for best sound quality. Sync
the picture and adjust the picture control for slightly less
than normal contrast. Turn the horizontal hold control to the
extreme position in which the oscillator fails to hold or to
pull in. Momentarily remove the signal. Turn the T301 fre¬
quency adjustment on the chassis rear apron until the oscil¬
lator pulls into sync. Check hold and pull-in for the other
extreme position of the hold control.
Complete Realignment—Tune in a Television Station and adjust
the fine tuning contiol for best sound quality.
With the sync link in the normal position (2-3), turn the T301
frequency adjustment (on rear apron), until the picture is syn¬
chronized. (If the picture is not synchronized vertically, adjust
the vertical hold.) Adjust the picture control so that the pic¬
ture is somewhat below average contrast level.
I urn the T301 phase adjustment screw (under chassis, see Fig¬
ure 23) until the blanking bar, which may appear in the pic¬
ture, moves to the right and off the raster. The range of this
adjustment is such that it is possible to hit an unstable condi-
ion (ripples in the raster). The screw must be turned clock¬
wise from the unstable position. The length of stud beyond
the bushing in its correct position is usually about Vz inch.
Turn horizontal hold to extreme counterclockwise position.
Turn T301 frequency adjustment clockwise until the picture
falls out of sync. Then turn it slowly counterclockwise to the
point where the picture falls in sync again.
Readjust T301 phase adjustment so that the left side of the
picture is close to the left side of the raster, but does not begin
to fold over.
Turn horizontal hold to extreme clockwise. The right side of
the picture should be close to the right side of the raster, but
should not begin to fold over. If it does, readjust the phase.
Momentarily remove the signal. When the signal is restored,
the picture should fall in sync. If it doesn't, turn T301 fre¬
quency adjustment counterclockwise until the picture falls in
sync.
Turn horizontal hold to extreme counterclockwise position. Re¬
move the signal momentarily. When signal is restored, the
picture should fall in sync.
NOTE: If the picture does not pull in sync after momentary
removals of signal in both extreme positions of horizontal hold,
the pull-in range may be inadequate, though not necessarily.
A pull-in through % of the hold control range may still be sat¬
isfactory.
There is a difference between the pull-in range and hold-in
range of frequencies. Once in sync, the circuit will hold
about 50% to 100% more variation in frequency than it can
pull in. The range of the horizontal hold control is only ap¬
proximately equal to the pull-in range, considerable variation
may be found due to variations in the cut-off characteristic
of the horizontal oscillator control tubes, V303.
Excessive pull-in is objectionable because the higher sensi¬
tivity of the control circuits means also greater susceptibility
to noise, and to the vertical sync and equalizing pulses which
tend to cause a bend in the upper part of the raster. This
effect is more noticeable when the sync link is in the 1-2 po¬
sition.
Now that a picture has been obtained we may proceed with
the picture adjustments.
Adjust the electrical and optical focusing adjustments for
maximum definition in the vertical wedge of the test pattern.
HEIGHT AND VERTICAL LINEARITY ADJUSTMENTS- • Adjust
the height control (R149 on r-f, i-f chassis rear apron) until the
picture fills the screen vertically. Adjust vertical linearity
(R175 on rear apron), until the test pattern is symmetrical from
top to bottom. Adjustment of either control will require a re¬
adjustment of the other. Adjust vertical centering to align the
picture with the mask. In some cases it may be necessary to
shift the position of the kinescope in the holder (see Figure 3)
in order to obtain proper centering of the picture.
8

INSTALLATION INSTRUCTIONS
303
VERTICAL HEIGHT VERTICAL
LINEARITY CONTROL CENTERING
Figure 6 — R-F, I-F Rear Chassis Adjustments
WIDTH AND HORIZONTAL LINEARITY ADJUSTMENTS—Turn
the horizontal drive, R340, clockwise as far as possible without
causing crowding of the right of the picture. Adjust the hori¬
zontal linearity control, R351, until the test pattern is sym¬
metrical left to right. A slight readjustment of the horizontal
drive control may be necessary when the linearity control is
used. Adjust the width control, L302, until the picture just fills
the screen horizontally. Adjust horizontal centering to align the
picture with the mask. In some cases it may be necessary to
shift the position of the kinescope in the holder in order to
obtain proper centering of the picture.
Do not turn the horizontal drive control beyond approximately
/& of its maximum clockwise position. To do so may cause the
output stage to oscillate and result in the loss of horizontal sync.
Figure 7—Horizontal Deflection Chassis Adjustments
FOCUS—Adjust the focus control for maximum definition in
the test pattern vertical "wedge." Adjust the optical focus
adjustment for best overall focus on the screen.
Tighten all yoke and optical barrel lock screws.
Pull the dust cover down around the top of the optical barrel
and tie it securely in place. Tie the cable sleeve tight around
the leads. These precautions are very important for if dust is
permitted to enter and settle on the corrector lens, the optical
efficiency of the system will be greatly impaired.
CHECK OF R-F OSCILLATOR ADJUSTMENTS—Tune in all
available television stations to see if the receiver r'-f oscillator
is adjusted to the proper frequency on all channels. If adjust¬
ments are required, these should be made by the method
outlined in the alignment procedure on page 22 • The adjust-
848PTK, 648P¥
ments for channels 1 through 5 and 7 through 12 are available
from the front of the cabinet by removing the station selector
escutcheon as shown in Figure 8. Adjustments for channels 6
and 13 are under the chassis. See Figure 17.
Figure 8 — R-F Oscillator Adjustments
VIDEO PEAKING SWITCH—A video peaking switch is pro¬
vided (see Figure 6) to permit changing the video response.
Normally the switch should be left open. However, if the pic¬
tures from the majority of stations look better with the switch,
closed, the switch should be closed. If transients are produced
on high contrast pictures, the switch should be left open.
ANTENNA TRAP—A series resonant trap across the r-f ampli¬
fier grid circuit is provided to eliminate interference from an
FM station on the image frequency of a television station or
interference on channel 6 from a station on channel 10 or on
channel 5 from a station on channel 7. To adjust the trap in
the field, tune in the station on which the interference is
observed. Tune both cores of the trap for minimum interference
in the picture. See Figure 16 for the location of the trap. Keep
both cores approximately the same by visual inspection. Then,
turn one core V 2 turn from the original position and repeak the
second for maximum rejection. Repeat this process until the
best rejection is obtained.
RADIO OPERATION—Turn the receiver function switch to AM
and FM positions and check the radio for proper operation.
PUSH-BUTTON ADJUSTMENT—To adjust the radio push but¬
tons, set the function switch to the broadcast band position,
tune the receiver to the desired station. Adjust the push but¬
tons as instructed on page 81 .
Figure 9 — Push-Button Adjustments
Select the proper station call letter tab, moisten the back of
it and insert in the appropriate recess in the push button bezel.
Place the tab cellophane cover in the recess over the tab.
Replace the cabinet back. Make sure the screws which hold
the back in place are tight, otherwise it may rattle or buzz
when the receiver is operating at high volume.

304
648PTK , 648PV INSTALLATION INSTRUCTION TABLE
The following table is provided as a check-off list for use when installing the receivers.
Step
Nc.
Proceed as Indicated
1
Remove front of shipping carton.
■
Slide cabinet out of carton.
3
Remove cabinet back.
■
Take off two nuts inside cabinfei and remove cab¬
inet from skid.
■
Unpack yokes, knobs, anode clip, and kinescope
holder ball head screws.
6
Remove shipping materials.
■
Remove radio brackets.
8
Remove shipping tapes.
9 Install control knobs.
10 Make sure all tubes are firmly seated in their
sockets.
11 Remove optical barrel dust cover.
12
Remove corrector lens and warning label.
n
Clean screen and mirrors.
n
Insert test lamp in kinescope holder.
15
Replace corrector lens, cover center hole.
16
Misadjust optical focus.
17
Check optical, horizontal and lateral centering.
m
Adjust centering if necessary.
19
Adjust corrector lens centering if necessary.
■
Refocus.
H
If focus is uneven, adjust optical barrel tilt.
22
Repeat steps 17 through 21 if necessary to obtain
proper resolution.
23 Remove corrector lens.
24
Remove test lamp.
25
Unpack and clean kinescope.
H
Insert kinescope in kinescope holder.
27
Clean and replace corrector lens.
Step
No. Proceed as Indicated
H
Install deflection yoke, connect cables and kinescope
socket.
B
Check all chassis interconnecting cables.
Remove high voltage capacitors shipping strings.
B
Connect receiver to an a-c line and antenna.
32
Turn receiver on, function switch to Tel.
33
Tune in station per Operating Instructions, steps 3
through 10.
34 Adjust electrical and optical focus control.
35
Check horizontal oscillator for hold and pull-in with
horizontal hold control at each extreme.
36 Align horizontal oscillator (T301) if necessary.
37 Rotate yoke for horizontal pattern, tighten.
38
Adjust height and vertical linearity and vertical
centering controls.
39
Adjust width, horizontal drive, linearity and hori¬
zontal centering controls.
40
Adjust focus control R331 for max definition of ver¬
tical wedge and optical focus adjustment for best
overall focus.
41
MAKE SURE ALL OPTICAL ADJUSTMENT LOCKS
ARE TIGHT.
B
Replace optical barrel dust cover.
B
Check r-f oscillator frequency on all channels.
44 Observe picture from all available stations.
45 Set video peaking switch S101
46
Check radio for operation on BC, SW, and FM
bands.
47
Set push buttons.
48
Adjust antenna trap.
U
Insert station call letter tabs in push button es¬
cutcheon.
50
Replace cabinet back.