RCA 8TS30 Mounting instructions

271
|p rcaVictor
TELEVISION RECEIVER
MODEL §1530
Chasils No, KCS 20J-1 (60 cycles) and
KCS 20K-2 (50 cycles)— Mh, No, 274
Service data
— 1948 No. T1 —
RADIO CORPORATION OF AMERICA
RCA VICTOR DIVISION
Model STS30
CAMDEN, N. J., U. S. A.
Walnut, Mahogany or Toasted Mahogany
GENERAL DESCRIPTION
Model 8TS30 is a thirty-tube, direct-viewing, 10" table model,
Television Receiver. The receiver is complete in one unit and
is operated by the use of seven front-panel controls. Features
of the receiver include: Full thirteen channel coverage; F-M
sound system; Improved picture brilliance; A-F-C horizontal
hold; Stabilized vertical hold; Two stages of video amplifica¬
tion; Noise saturation circuits; Three stage sync separator and
clipper; Four me. band width for picture channel, and Re¬
duced hazard high voltage supply.
ELECTRICAL AND MECHANICAL SPECIFICATIONS
PICTURE SIZE . GVa" x 8Vi"—-2" radius at comer
R-F FREQUENCY RANGES
Picture Sound
Receiver
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.
.93
5. .76-82.
.77.25. .81.75. .103
6.
.82-88. .83.25.
.87.75.
.109
7..........
...174-180....... .175.25.
.179.75.. .201
8.
...180-186.
.181.25.
.185.75.
.207
9.......... ...186-192. .187.25.
.191.75.
.213
10.
...192-198.
.193.25.
.197.75.
.219
11 .
... 1 9 8-204 .
.199.25.
. 203.75 . .225
12 ..........
... 204 - 210 .......
..... 205 . 2 5 ........
...... 209 .75. . . . ..
.231
13 . ...210-216.
.211.25.
.215.75. .237
F’WE TUNING RANGE
Plus and minus approximately 300 kc on channel 1 and plus
and minus approximately 750 kc on channel 13.
POWER SUPPLY HATING
KCS 20J-1 .115 volts,, 60 cycles, 320 watts
KCS 20K-2 .115 volts, 50 cycles, 320 watts
AUDIO POWER OUTPUT RATING
Undistorted ... 2.5 watts
Maximum . 4 watts
LOUDSPEAKER (92573-2)
Typo .. 5x7 inch Permanent Magnet Dynamic
Voice Coil Impedance . 3.2 ohms at 400 cycles
WEIGHT
Chassis with Tubes in Cabinet (less Kinescope) . 80 lbs.
Shipping Weight . 93 lbs.
RECEIVER ANTENNA INPUT IMPEDANCE. .300 ohms balanced
DIMENSIONS (inches) Length Height Depth
Cabinet (Outside ... 26 14 Vi 19
Chassis Base (Outside) . 19 Vi 3 Vi 15 Vi
Chassis Overall . 21 3 /i 11% 16 V4
RCA TUBE COMPLEMENT
Tube Used Function
(1) RCA 6J6 ... R-F Amplifier
(2) RCA 6J6 . R-F Oscillator
(3) RCA 6J6 . Converter
(4) RCA 6BA6 . 1st Sound I-F Amplifier
(5) RCA 6BA6 . 2nd Sound I-F Amplifier
(6) RCA 6AU6 . 3rd Sound I-F Amplifier
(7) RCA SALS ... Sound Discriminator
(8) RCA 6AT6 . 1st Audio Amplifier
(9) RCA 6K6GT ... Audio Output
(10) RCA 6AG5 . 1st Picture I-F Amplifier
(11) 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 D-C Restorer
(15) RCA 6AU6 . 1st Video Amplifier
(16) RCA 6K6GT . 2nd Video Amplifier
(17) RCA 6SK7 . 1st Sync Amplifier
(18) RCA 6SH7 . Sync Separator
(19) RCA 6SN7GT . 2nd Sync Amplifier and Horizontal
Discharge
(20) RCA 6J5 .Vertical Sweep Oscillator and Discharge
(21) RCA 6K6GT . Vertical Sweep Output
(22) RCA 6AL5 .,... Horizontal Sync Discriminator
(23) RCA 6K6GT .. Horizontal Sweep Oscillator
(24) RCA 6AC7 . Horizontal Sweep Oscillator Control
(25) RCA 8BG6G ... Horizontal Sweep Output
(26) RCA 5V4G . Horizontal Reaction Scanning
(27) RCA 1B3-GT/8016 .... High Voltage Rectifier
(28) RCA 5U4G . Power Supply Rectifiers (2 tubes)
(29) RCA 10BP4 ... Kinescope
Specifications continued on page 2
1

272
8TS30 ELECTRICAL AND MECHANICAL SPECIFICATIONS (Continued)
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.
OPERATING CONTROLS (front panel)
Channel Selector (
Fine Tuning ( .
Picture i
Sound Volume and On-Off Switch |
.Dual Control Knobs
.Dual Control Knobs
SOUND I-F FREQUENCIES
Sound Carrier Frequency .. 21.25 Me.
Sound Discriminator Band Width between peaks) . 350 kc
Picture Horizontal Hold
Picture Vertical Hold
.Dual Control Knobs
Brightness
Single Control Knob
VIDEO RESPONSE . To 4 Me.
FOCUS ...... ... Magnetic
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 & i-f adjust¬
ments)
Horizontal Centering . rear chassis adjustment
Vertical Centering . rear chassis adjustment
Width . rear chassis screwdriver adjustment
Height . rear chassis adjustment
Horizontal Linearity . top chassis screwdriver adjustment
Vertical Linearity . rear chassis adjustment
Horizontal Drive.... rear chassis adjustment
Horizontal Oscillator Frequency . rear chassis adjustment
Horizontal Oscillator Phase . bottom chassis adjustment
h’oeus . rear chassis adjustment
Focus Coil . top chassis wing nut adjustment
Ion Trap Magnet . top chassis thumb screw adjustment
Deflection Coil . top chassis wing nut adjustment
HIGH VOLTAGE WARNING
OPERATION OF THIS RECEIVER OUTSIDE THE CABINET OR WITH THE COVERS REMOVED, INVOLVES
A SHOCK HAZARD FROM THE RECEIVER POWER SUPPLIES. WORK ON THE RECEIVER SHOULD NOT
BE ATTEMPTED BY ANYONE WHO IS NOT THOROUGHLY FAMILIAR WITH THE PRECAUTIONS NECES¬
SARY WHEN WORKING ON HIGH VOLTAGE EQUIPMENT. DO NOT OPERATE THE RECEIVER WITH THE
HIGH VOLTAGE COMPARTMENT SHIELD REMOVED.
KINESCOPE HANDLING PRECAUTIONS
DO NOT OPEN THE KINESCOPE 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 KINESCOPES. 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 care than ordinary receiving tubes.
I he large end of the kinescope bulb particularly that part at the rim of the viewing surface—must not be struck, scratched or sub¬
jected to more than moderate pressure at any time. In installation, if the tube sticks or fails to slip smoothly into its socket, or de¬
flecting yoke, investigate and remove the cause of the trouble. Do not force the tube. Refer to the Receiver Installation section for de¬
tailed 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.
2

273
OPERATING INSTRUCTIONS 8TS30
The iollowing adjustments are necessary when turning the
receiver on for the first time.
1. Turn the receiver "ON" and advance the SOUND VOL¬
UME control to approximately mid-position.
2. Set the STATION SELECTOR to the desired channel.
3. Turn the PICTURE control fully counter-clockwise.
4. Turn the BRIGHTNESS control clockwise, until a glow
appears on the screen then counter-clockwise until the glow
just disappears.
5. Turn the PICTURE control
clockwise until a glow or pat¬
tern appears on the screen.
6. Adjust the FINE TUNING
control for best sound fidelity
and SOUND VOLUME for suit¬
able volume.
7. Adjust the VERTICAL hold
control until the pattern stops
vertical movement.
8. Adjust the HORIZONTAL
hold control until a picture is ob¬
tained and centered.
9. Adjust the PICTURE control for suitable picture con¬
trast.
10. After the receiver has been on for some time, it may be
necessary to readjust the FINE TUNING control slightly for
improved sound fidelity.
11. In switching from one station to another, it may be
necessary to repeat steps number 6 and 9.
12. When the set is turned on again after an idle period,
it should not be necessary to re¬
peat the adjustments if the posi¬
tions of the controls have not
been changed. If any adjust¬
ment is necessary, step number
6 is generally sufficient.
13. I f the positions of the con¬
trols have been changed, it may
be necessary to repeat steps
number 1 through 9.
NOTE: If any difficulty is ex¬
perienced with steps number 7
or 8, turn the PICTURE control
Vi turn counterclockwise and re¬
peat those adjustments.
Figure 1—Receiver Operating Controls
INSTALLATION INSTRUCTIONS
The Model 8TS30 television receiver is shipped complete in
one carton except for the 10BP4 kinescope. The kinescope is
shipped in a special carton and should not be unpacked until
ready for installation.
UNPACKING—To unpack the receiver, tear open the carton
bottom flaps, pick the receiver up from under the bottom
of the cabinet and lift it out of the shipping carton.
The cabinet safety glass front panel is packed in a cardboard
box. Remove the box and unpack the panel. Take off the
cabinet top and back.
The operating control knobs are packed in a paper bag which
is tied to the inside of the cabinet brace. Remove the bag.
Remove the protective cardboard shield from the 5U4G recti¬
fier. Make sure all tubes are in place and are firmly seated
in their sockets.
Loosen the two kinescope cushion adjustment wing screws and
slide the cushion toward the rear of the chassis. Loosen the
deflection yoke adjustment, slide the yoke toward the rear
of the chassis and tighten. See Figure 2 for the location of
the cushion and yoke adjustments.
\ FRONT MAGNET GAP
ON THIS SIDE AND EVEN
WITH REAR MAGNET GAP
Figure 2—Yoke and Focus Coil Adjustments
From the front of the cabinet, look through the deflection yoke
and check the alignment of the focus coil with the yoke. If
the focus coil is not in line, loosen the three focus coil adjust¬
ment wingnuts and raise, lower, or rotate the coil until align¬
ment is obtained. Tighten the wingnuts with the coil in this
position.
Loosen the two lower kinescope face centering slides, and set
them at approximately mid position. See Figure 3 for loca¬
tion of the slides and their adjustment screws.
TO INSTALL CABINET FRONT PANEL, INSERT THESE SCREWS
SLIDES SCREWS
Figure 3— Cabinet, Front View
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.
3

274
8TS30 INSTALLATION INSTRUCTIONS
INSTALLATION OF KINESCOPE—The kinescope second anode
contact is a recessed metal well in the side of the bulb. The
tube must be installed so that this contact is approximately on
top. The final orientation of the tube will be determined by
the position of the ion trap flags. Looking at the kinescope
gun structure, it will be observed that the second cylinder from
the base inside the glass neck is provided with two small
metal flags, as shown in Figure 4. The kinescope must be
installed so that when looking down on the chassis, the two
flags will be seen as shown in Figure 2.
Figure 4—loti Trap Flags
Insert the neck of the kinescope through the deflection and
focus coils as shown in Figure 5 until the base of the tube
protrudes approximately two inches beyond the focus coil.
If the tube sticks, or fails to slip into place smoothly, investi¬
gate and remove the cause of the trouble. Do not force the
tube.
Early production receivers employed an EM type of ion trap
magnet like that in the model 630TS receiver. Late production
receivers employed a PM type magnet as shown in Figure 2.
If an EM type of magnet is applied, slip the assembly over
the neck of the kinescope with the coils down and the large
coil towards the base of the tube. Tighten the magnet ad¬
justment thumbscrews sufficiently to hold it in position but still
free enough to permit adjustment.
If the PM type is employed, slip the assembly over the neck
of the kinescope with the large magnet towards the base of
the tube and with the arrow on the assembly up as shown in
Figure 2. The front magnet is movable on the assembly. The
correct position of the front magnet is with the gap on the left
side (from the rear of the cabinet) and even with the gap of
the rear magnet.
Connect the kinescope socket to the tube base. Insert the
kinescope until the face of the tube protrudes approximately
one-quarter of an inch outside the front of the cabinet. Ad¬
just the four centering slides until the face of the kinescope is
in the center of the cabinet opening. Tighten the four slides
securely.
Wipe the kinescope screen surface and front panel safety
glass clean of all dust and finger marks with a soft cloth
moistened with the Drackett Co's "Windex" or similar cleaning
agent.
Install the cabinet front panel as indicated in Figure 3.
To install the front panel place the lip on the bottom of the
panel in the recess below the kinescope opening and push the
top in. Insert the two screws from the bag with the knobs into
the back of panel as shown in Figure 3.
Slip the kinescope as far forward as possible. Slide the
kinescope cushion firmly up against the flare of the tube and
tighten the adjustment wing screws. Slide the deflection
yoke as far forward as possible. Connect the high voltage
lead to the kinescope second anode socket.
The antenna and power connections should now be made.
Turn the power switch to the "on" position, the brightness
control fully clockwise, and picture control counter-clockwise.
ION TRAP MAGNET ADJUSTMENT—The ion trap rear magnet
poles should be approximately over the ion trap flags as
shown in Figure 2. Starting from this position adjust the mag¬
net by moving it forwards or backwards at the same time ro¬
tating it slightly around the neck of the kinescope for the
brightest raster on the screen. Reduce the brightness control
setting until the raster is slightly above average brilliance.
Adjust the focus control (R184 on the chassis rear apron) until
the line structure of the raster is clearly visible. Readjust
the ion trap magnet for maximum raster brilliance. The final
touches on this adjustment should be made with the brightness
control at the maximum position with which good line focus
can be maintained.
FOCUS COIL ADJUSTMENTS—Turn the centering controls R181
and R211 to mid position. See Figure 6 for location of these
rear apron controls.
If a corner of the raster is shadowed, it indicates that the
electron beam is striking the neck of the tube. Loosen the
focus coil adjustment wing nuts and rotate the coil about its
vertical and horizontal axis until the entire raster is visible,
approximately centered and with no shadowed corners. Tighten
the focus coil adjustment wing nuts with the coil in this posi¬
tion.
Figure 6—Rear Chassis Adjustments
DEFLECTION YOKE ADJUSTMENT—If the lines of the raster
are not horizontal or squared with the picture mask, rotate
the deflection yoke until this condition is obtained. Tighten
the yoke adjustment wing screw.
PICTURE ADJUSTMENTS—It will now be necessary to obtain a
test pattern picture in order to make further adjustments. See
steps 2 through 9 and the note of the receiver operating in¬
structions on page 3.
CHECK OF HORIZONTAL OSCILLATOR ALIGNMENT—Turn
the horizontal hold control to the extreme counter-clockwise
position. The picture should remain in horizontal sync. Mo¬
mentarily remove the signal by switching off channel then
back. Normally the picture will pull into sync. Turn the
horizontal hold control to the extreme clockwise position. The
picture should remain in sync. Momentarily remove the sig¬
nal. 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.
Skip "Alignment of Horizontal Oscillator and proceed with
'FOCJJS' adjustment."
4

275
INSTALLATION INSTRUCTIONS 8IS30
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
pul in. Momentarily remove the signal. Turn the T10$ 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 ad¬
just the fine tuning control for best sound quality.
Turn the T108 frequency adjustment on rear apron until the
picture is synchronized. Adjust the picture control so that the
picture is somewhat below average contrast level.
Turn the T108 phase adjustment screw (under chassis) until
the blanking bar, which may appear in the picture, moves
to the right and off the raster. The range of this adjustment
is such that it is possible to hit an unstable condition (ripples
in the raster). The screw must be turned clockwise from the
unstable position. The length of stud beyond the bushing in
its correct position is usually about V 2 inch.
Turn horizontal hold to the extreme counter-clockwise position.
Turn T108 frequency adjustment clockwise until the picture
falls out of sync. Then turn it slowly counter-clockwise to the
point where the picture falls in sync again.
Readjust T108 phase adjustment so that the left side of the pic¬
ture is close to the left side of the raster, but does not begin to
fold ever.
Turn horizontal hold to the extreme clockwise position. 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 control.
Momentarily remove the signal. When the signal is re¬
stored, the picture should fall in sync. If it doesn't, turn T108
frequency adjustment counter-clockwise until the picture falls
in sync.
Turn horizontal hold to the extreme counter-clockwise position.
Remove the signal momentarily. When signal is restored, the
picture shuuld fall in sync.
NOTE: If the picture does not pull in sync after momentary
removals of the signal in both extreme positions of horizontal
hold, the pull-in range may be inadequate, though not neces¬
sarily. A pull-in through % of the hold control range may
still be satisfactory.
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, V124.
FOCUS—Adjust the focus control R184 for maximum definition
of tho vertical wedge of the test pattern.
HEIGHT AND VERTICAL LINEARITY ADJUSTMENTS—Adjust
the height control (R169 on chassis rear apron) until the picture
fills the mask vertically (6 3 /s inches). Adjust vertical linearity
(R178 on rear apron), until the test pattern is symmetrical from
top to bottom. Adjustment of either control will require a read¬
justment of the other. Adjust vertical centering to align the
picture with the mask.
WIDTH AND HORIZONTAL LINEARITY ADJUSTMENTS—Turn
the horizontal drive (R187 on rear apron) clockwise as far as
possible without causing crowding of the right of the picture.
This position provides maximum high voltage to the kine¬
scope second anode. Adjust the width control (LI96 on rear
chassis) until the picture just fills the mask horizontally (8 V 2
inches). Adjust the horizontal linearity control L201 (see Fig¬
ure 6) until the test pattern is symmetrical left to right. A
slight readjustment of the horizontal drive control may be
necessary when the linearity control is used. Adjust horizontal
centering to align the picture with the mask.
If repeated adjustments of drive width and linearity fail to give
proper linearity, it may be necessary to move the tap on R209,
which is located in the high voltage compartment. Adjust¬
ments of drive, width and linearity must then be repeated.
Check to see that all cushion, yoke, focus coil and ion trap
magnet thumb screws are tight. Replace the cabinet back
and top. Make sure that the back is on tight, otherwise it
may rattle at high volume.
CHECK OF R-F OSCILLATOR ADJUSTMENTS—With a crystal
calibrated test oscillator or heterodyne frequency meter, check
to see if the receiver r-f oscillator is adjusted to the proper
frequency on all channels. If adjustments are required, these
should be made by the method outlined in the alignment pro¬
cedure on page 8. The adjustments 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 7. Adjustments for channels 6 and 13 are under the
chassis.
VIDEO PEAKING LINK—A video peaking link is provided
(see Figure 6) to permit changing the video response. If the
pictures from the majority of stations look better with the
link closed, (2-3 position) then the link should be placed in
that position. However, if transients are produced on high
contrast pictures then the link should be left open (1-2 position).
Figure 7 — R-F Oscillator Adjustments
ANTENNA TRAP—In some instances interference may be en¬
countered from FM stations that are on the image frequency of
a television station. In other instances interference between
two television stations may be observed.
Assume that two television stations in a city are operating on
channels 6 and 10. When the receiver is tuned to channel 6,
a small amount of the oscillator voltage (109 me.) is present
on the r-f amplifier grid. This 109 me. voltage beats with the
channel 10 picture carrier and produces an 84.25 me. signal.
This signal falls within the channel 6 range and interferes
with the reception of channel 6. A similar case occurs be¬
tween channels 5 and 7.
A series resonant trap across ther-f amplifier grid circuit is
employed to remove theoscillator voltage from the grids and
thus eliminate this type of interference.
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 8 for the lo¬
cation 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 rejec¬
tion Repeat this process until the best rejection is obtained.
For shop alignment of the trap see the alignment procedure on
page 11.
In severe cases of interference, it may be necessary to reduce
the signal from the interfering station by reorienting the an¬
tenna or by connecting a half wave stub of transmission line
across the receiver antenna terminals. The end of the stub
should be terminated by a 47 ohm, non inductive resistor.
5

276
8TS30
CHASSIS TOP ¥1EW
\ R\BZ
&R10MTNB SS
CONTROL
sm
VERTICAL
MOLD CONTROL
WIGM VOLTAGE COMPARTMENT
(SHOWN WITH SUIELO REMOVED)

BOTTOM VIEW
8TS30
R ! B 2
Figure 9—Chassis Bottom View

278
ALIGNMENT PROCEDURE
8 fS30
TEST EQUIPMENT —To properly service the television chassis
of this receiver, it is recommended that the following test
equipment be available:
R-F Sweep Generator meeting the following requirements;
(a) Frequency Ranges
18 to 30 me., 1 me. sweep width
40 to 90 me., 10 me. sweep width
170 to 225 me., 10 me. sweep width
(b) Output adjustable with at least .1 volt maximum.
(c) Output constant on all ranges.
(d) "Flat” output on all attenuator positions.
Cathode-ray Oscilloscope, preferably one with a wide band
vertical deflection, an input calibrating source, and a low ca¬
pacity probe.
Signal Generator to provide the following frequencies.
(a) I-F frequencies
19.75 me. adjacent channel picture trap
21.25 me. sound i-f and sound traps
21.8 me. converter transformer
22.3 me. second picture i-f transformer
23.4 me. fourth picture i-f coil
25.2 me. third picture i-f coil
25.3 me. first picture i-f transformer
25 75 me. picture carrier
27.25 me. adjacent channel sound trap
(b) R-F frequencies
Picture
Sound
Channel
Carrier
Carrier
Number
Freq. Me.
Freq. Me.
1 .
.. 45.25 .
. 49.75
2 .
.. 55.25 .
. 59.75
3 .
.. 61.25 .
. 65.75
4 .
.. 67.25 .
. 71.75
5 .
.. 77.25 .
. 81.75
6 .
.. 83.25 .
. 87.75
7 .
.. 175.25 .
. 179.75
8 .
.. 181.25 .
. 185.75
S .
.. 187.25 .
. 191.75
10 .
.. 193.25 .
. 197.75
11 .
.. 199.25 .
. 203.75
12 .
.. 205.25 .
. 209.75
13 .
... 211.25 .
215.75
(c) Output on these ranges should be adjustable and at least
.1 volt maximum.
Heterodyne Frequency Meter with crystal calibrator if the sig¬
nal generator is not crystal controlled.
Electronic Voltmeter of Junior "VoltOhmyst" type and a high
voltage multiplier probe for use with this meter to permit
measurements up to 10 kv.
Service Precautions—If necessary to remove the chassis from
cabinet, the kinescope must first be removed. See Figures 3
and 5. If possible, the chassis should then be serviced without
the kinescope. However, if it is necessary to view the raster
during servicing, the kinescope should be inserted only after
the chassis is turned on end. The kinescope should never be
allowed to support its weight by resting in the deflecting yoke.
A bracket should be used to support the tube at its viewing
screen.
By turning the chassis on end with the power transformer
down, all adjustments will be made conveniently available.
Since this is the only safe position in which the chassis will
rest and still leave all adjustments accessible, the trimmer
location drawings are oriented similarly for ease ol use.
CAUTION: Do not short the kinescope second anode lead.
Its short circuit current is approximately 3 ma. This repre¬
sents approximately 9 watts dissipation and a considerable
overload on the high voltage filter resistor R235.
Adjustments Required—Normally, only the r-f oscillator line
will require the attention of the service technician. All other
circuits are either broad or very stable and hence will seldom
require re-adjustment.
Due to the high frequencies at which the receiver operates the
r-f oscillator line adjustment is critical and may be affected by
a tube change. The line can be adjusted to proper frequency
on channel 13 with practically any 6J6 tube in the oscillator
socket. However, it may not then be possible to adjust the
line to frequency on all of channels 7, 8, 9, 10, 11 and 12.
To be satisfactory as an oscillator tube, it should be possible
to adjust the line to proper frequency with the fine tuning
control in the middle third of its range. It may therefore be
necessary to select a tube for the oscillator socket. In replac¬
ing, if the old tube can be matched for frequency by trying
several new ones, this practice is recommended. At best,
however, it will probably be necessary to completely realign
the oscillator line when changing the tube.
Tubes which cannot be used as oscillator will work satisfac¬
torily as r-f amplifier or converter.
ORDER OF ALIGNMENT—When a complete receiver align¬
ment is necessary, it can be most conveniently performed in
the following order;
Sound discriminator
Sound i-f transformers
Picture i-f traps
Picture i-f transformers
R-F and converter lines
R-F oscillator line
Retouch picture i-f transformers
Antenna trap adjustment
Sensitivity check
SOUND DISCRIMINATOR ALIGNMENT—
Set the signal generator for approximately .1 volt output at
21.25 m e. and connect it to the third sound i-f grid.
Detune T113 secondary (bottom).
Set the "VoltOhmyst” on the 10 volt scale.
Connect the meter in series with a one megohm resistor to the
junction of diode resistors R219 and R220. Do not remove the
discriminator shield to make connection to R219 and R220.
Connection can be easily made by fashioning a hook on the
1 meg resistor lead and making connection to the transformer
lug "C" through the hole provided for the adjusting tool.
Adjust the primary of T113 (top) for maximum output on the
meter.
Connect the "VoltOhmyst" to the junction of R236 and C205.
Adjust T113 secondary (bottom). It will be found that it is pos¬
sible to produce a positive or negative voltage on the meter de¬
pendent upon this adjustment. Obviously to pass from a posi¬
tive to a negative voltage, the voltage must go through zero.
T113 (bottom) should be adjusted so that the meter indicates
zero output as the voltage swings from positive to negative.
This point will be called discriminator zero output.
Connect the sweep oscillator to the grid of the third sound
i-f amplifier.
8

ALIGNMENT PROCEDURE
8TS30
Adjust the sweep band width to approximately 1 me. with
the center frequency at approximately 21.25 and with an
output of approximately .1 volt.
Connect the oscilloscope to the junction of R236 and C205.
The pattern obtained should be similar to that shown in
Figure 16A. If it is not. adjust the T113 (top) until the wave
form is symmetrical.
The peak to peak bandwidth of the discriminator should be
approximately 350 kc. and it should be linear from 21.75 me.
to 21.325 me.
SOUND I-F ALIGNMENT—
Connect the sweep oscillator to the second sound i-f amplifier
grid.
Connect the oscilloscope to the third sound i-f grid return
(terminal A T112) in series with a 33,000 ohm isolating resistor.
Insert a 21.25 me. marker signal from the signal generator into
the second sound i-f grid.
Adjust T112 (top and bottom) for maximum gain and sym¬
metry about the 21.25 me. marker. The pattern obtained should
be similar to that shown in Figure 16B.
The output level from the sweep should be set to produce
approximately .3 volt peak-to-peak at the third sound i-f grid
return when the final touches on the above adjustment
are made. It is necessary that the sweep output voltage
should not exceed the specified values otherwise the response
curve will be broadened, permitting slight misadjustment to
pass unnoticed and possibly causing distortion on weak
signals.
Connect the sweep and signal generator to the top end of the
trap winding of T2 (on top of the chassis). Adjust Till (top
and bottom), for maximum gain and symmetry at 21.25 me.
Reduce the sweep output for the final adjustments so that
approximately .3 volt peak-to-peak is present at the third
sound i-f grid return.
The band width at 70% response from the first sound i-f grid
to the third i-f grid should be approximately 200 kc.
PICTURE I-F TRAP ADJUSTMENT—
Turn the receiver picture control for -3 volts on the picture
i-f grids.
Set the channel switch to channel 13.
Connect the "VoltOhmyst" across the picture second detector
load resistor R137.
Connect the output of the signal generator to the junction of
C14 and R6. This connection is available on a terminal lug
through a hole in the side apron of the chassis, beside the r-f
unit. This hole is normally down when the chassis is in the
recommended position. Connection can be easily made, how¬
ever, by allowing the receiver to hang over the edge of the
test bench by a few inches.
Set the generator to each of the following frequencies and
tune the specified adjustment for minimum indication on the
"VoltOhmyst." In each instance the generator should be
checked against a crystal calibrator to insure that the gen¬
erator is exactly on frequency
21.25 m e.—T2 (top)
21.25 me.—T105 (top)
27.25 me.—T103 (top)
27.25 m e.—T102 (bottom)
19.75 me.- 1 T104 (top)
Note—On some sets, T102 bottom adjustment is omitted.
PICTURE I-F TRANSFORMER ADJUSTMENTS—
Set the signal generator to each of the following frequencies
and peak the specified adjustment for maximum indication on
the "VoltOhmyst,"
21.8 me.—T2 (bottom)
25.3 me.—T103 (bottom)
22.3 me.—T104 (bottom)
25.2 me.—T’02 (top of chassis)
23.4 me.—LI85 (top of chassis)
If T104 (bottom) required adjustment, it will be necessary to
reset T104 (top) for minimum response at 19.75 me.
Picture I-F Oscillation—If the receiver is badly misaligned and
two or more of the i-f transformers are tuned to the same
frequency, the receiver may fall into i-f oscillation. I-F oscilla¬
tion shows up as a voltage in excess of 3 volts at the picture
detector load resistor. This voltage is unaffected by r-f signal
input and sometimes is independent of picture control setting.
If such a condition is encountered, it is sometimes possible to
stop oscillation by adjusting the transformers approximately
to frequency by setting the adjustment stud extensions of T2,
T103, T104, T105, TT102, and L185 to be approximately equal
to those of another receiver known to be in proper alignment.
If this does not have the desired effect, it may now be possible
to stop oscillation by increasing the grid bias. If so, it should
then be possible to align the transformers by the usual method.
Once aligned in this manner, the i-f should be stable with
reduced bias.
If the oscillation cannot be stopped in the above manner,
shunt the grids of the first three pix i-f amplifiers to ground
with 1000 mmf. capacitors. Connect the signal generator to
the fourth pix i-f grid and align LI85 to frequency. Pro¬
gressively remove the shunt from each grid and align the
plate coil of that stage to frequency.
If this does not stop the oscillation, the difficulty is not due
to i-f misalignment as the i-f section is very stable when prop¬
erly aligned. Check all i-f by-pass condensers, transformer
shunting resistors, tubes, socket voltages, etc.
R-F AND CONVERTER LINE ADJUSTMENT—
Connect the r-f sweep oscillator to the receiver antenna ter¬
minals. If the sweep oscillator has a 50 ohm single-ended
output, it will be necessary to obtain balanced output by
connecting as shown in Figure 10.
Figure 10—Unbalanced Sweep Cable Termination
Connect the oscilloscope to the junction of C14 and R6 (in the
r-f tuning unit) through a 10,000 ohm resistor.
By-pass the first picture i-f grid to ground through a 1000 mmfd.
capacitor. Keep the leads to this by-pass as short as possible.
If this is not done, lead resonance may fall in the r-f range
and cause an incorrect picture of the r-f response.
Turn the picture control for —1.5 volts on the r-f grids. Connect
the signal generator loosely to the receiver antenna terminals.
Turn the antenna trap L81 and L82 cores fully counterclock¬
wise so that the trap will not affect the channel 6 r-f response.
Since channel 7 has the narrowest response of any of the

280
ALIGNMENT PROCEDURE
8TS30
high frequency channels, it should be adjusted first.
Set the receiver channel switch to channel 7 (see Figure 15
for switch shaft flat location versus channel).
Set the sweep oscillator to cover channel 7.
Insert markers of channel 7 picture carrier and sound carrier
175.25 me. and 179.75 me.
Adjust L25, L26, L51 and L52 (see Figure 17) for an approxi¬
mately flat topped response curve located symmetrically be¬
tween the markers. Normally this curve appears somewhat
overcoupled or double humped with a 10 or 15% peak to val¬
ley excursion and the markers occur at approximately 90% re¬
sponse. See Figure 17, channel 7. In making these adjust¬
ments, the stud extension of all cores should be kept approxi¬
mately equal.
Check the response of channels 8 through 13 by switching
the receiver channel switch, sweep oscillator and marker
oscillator to each of these channels and observe the response
obtained. See Figure 17 for typical response curves. It should
be found that all these channels have the proper shaped re¬
sponse with the markers above 70% response. It the markers
do not fall within this requirement on one or more high fre¬
quency channels, since there are no individual channel ad¬
justments, it will be necessary to readjust L25, L26, L51 and
L52, and possibly compromise some channel slightly in order
to get the markers up on other channels. Normally however,
no difficulty of this type should be experienced since the
higher frequency channels become comparatively broad and
the markers easily fall within the required range.
Channel 6 is next aligned in the same manner.
Set the receiver to channel 6.
Set the sweep oscillator to cover channel 6.
Set the marker oscillator to channel 6 picture and sound car¬
rier frequencies.
Adjust L11, L12, L37 and L38, for an approximately flat-topped
response curve located symmetrically between the markers.
Check channels 5 down through channel 1 by switching the
receiver, sweep oscillator and marker oscillator to each chan¬
nel and observing the response obtained. In all cases, the
markers should be above the 70% response point. If this is
not the case, LI I, L12, L37 and L.38 should be retouched. On
final adjustment, all channels must be within the 70% spec¬
ification.
Coupling between r-f and converter lines is augmented by
a link between LI2 and L37. This link is adjusted in the
factory and should not require adjustment in the field. On
channel 6 with the link in the minimum coupling position, the
response is slightly overcoupled with approximately a 10%
excursion from peak-to-valley. With the coupling at maximum,
the response is somewhat broader and the peak-to-valley ex¬
cursion is approximately 40%. The amount of coupling per¬
missible is limited by the peak-to-valley excursion which should
not be greater than 30% on any channel.
R-F OSCILLATOR LINE ADJUSTMENT—
The r-f oscillator line may be aligned by adjusting it to beat
with a crystal calibrated heterodyne frequency meter, or by
feeding a signal into the receiver at the r-f sound carrier fre¬
quency and adjusting the oscillator for zero output from the
sound discriminator. In this latter case the sound discriminator
must first have been aligned to exact frequency. Either method
of adjustment will produce the same results. The method used
will depend upon the type of test equipment available.
Regardless of which method of oscillator alignment is used,
the frequency standard must be crystal controlled or calibrated.
If the receiver oscillator is to be adjusted by the heterodyne
frequency meter method, the calibration frequency listed under
R-F Osc. Freq. must be available.
If the receiver oscillator
is adjusted by
feeding in the r-f
sound carrier
frequency,
the frequencies
listed under sound
carrier Freq.
must be available.
Receiver
R-F Sound
Channel
R-F Osc.
Carrier
Number
Freq, Me. Freq. Me.
1 .
. 71 . . 49.75
2 .
. 81 .
. 59.75
3 .
. 87 . . 65.75
4 .
. 93 .
. 71.75
5 .
. 103 . .. 81.75
6 .
. 109 .
. 87.75
7 .
. 201 .
. 179.75
8 . . 207 . .. 185,75
9 . . 213 . . 191.75
10 . . 219 .
. 197.75
11 .
. 225 .
.. 203.75
12 . . 231 . . 209.75
13 .
. 237 . . 215.75
If the heterodyne frequency meter method is used, couple the
meter probe loosely to the receiver oscillator.
If the r-f sound carrier method is used, connect the "Volt-
Ohmyst" to the sound discriminator output (junction of R236
and C205.
Connect the signal generator to the receiver antenna terminals.
The order of alignment remains the same regardless of which
method is used.
Since lower frequencies are obtained by adding steps of
inductance, it is necessary to align channel 13 first and con¬
tinue in reverse numerical order.
Set the receiver channel switch to 13.
Adjust the frequency standard to the correct frequency (237
me. for heterodyne frequency meter or 215.75 me. for the signal
generator).
Set the fine tuning control to the middle of its range while mak¬
ing the adjustment.
Adjust L77 and L78 for an audible beat on the heterodyne
frequency meter or zero voltage from sound discriminator. The
core stud extensions should be maintained equal by visual
inspection.
Switch the receiver to channel 12.
Set the frequency standard to the proper frequency as listed
in the alignment table.
Adjust L76 for indications as above.
Adjust the oscillator to frequency on all channels by switch¬
ing the receiver and the frequency standard to each channel
and adjusting the appropriate oscillator trimmer for the speci¬
fied indication. It should be possible to adjust the oscillator
to the correct frequency on all channels with the fine tuning
control in the middle third of its range.
After the oscillator has been set on all channels, start back at
channel 13 and recheck to make sure that all adjustments are
correct.
RETOUCHING OF PICTURE I-F ADJUSTMENTS—
The picture i-f response curve varies somewhat with change
of bias and for this reason it should be aligned with approxi-
10