Zenith A2221YI Disassembly Instructions Manual

PHOTOFACT* Folder
DISASSEMBLY
INSTRUCTIONS
CHASSIS REMOVAL
1. Remove 4 push-on type knobs from the front.
2. Remove 6 metal screws from the rear cover. Remove
the rear cover.
3. Remove 4 metal screws holding the tuner. Remove the
tuner.
4. Remove 2 metal screws holding the control bracket.
5. Remove the speaker leads.
6. Remove 4 chassis bolts from the bottom.
7. Remove the chassis.
MODEL A2221YlCh. 17A20)
TRADE NAME Zenith MODELS CHASSIS
MANUFACTURER
TYPE SET
TUBES
POWER SUPPLY
TUNING RANGE
A2221J, Y, A2223E, H, R, Y, A2245E, R, A2250M, R,
A2251E, R, A2282E, R, A2673E, R 17A20
A2221JU, YU, A2223EU, HU, RU, YU, A2245EU, RU,
A2250MU, RU, A2251EU, RU, A2282EU, RU, A2673EU, RU 17A20U
A3001E, H, R, A3006E, H, R, A3008E, R 17A20Q
A3000E, R. A3004, E, R 17A21Q
Zenith Radio Corp., 6001 Dickens Avenue, Chicago 39, Illinois
Television Receiver
Seventeen
110-120 Volts AC, 60 Cycle RATING 185 Watts, 1.6 Amp. © 117 Volts AC
Channels 2 thru 13 VHF, 14 thru 83 UHF, Video IF 45. 75MC, Sound IF 41. 25MC (Intercarrier)
SERVICING IN THE FIELD
TUNER OSCILLATOR ADJUSTMENTS
Touch-up adjustment of the VHF oscillator is possible by
removing the channel selector and fine tuning knobs. Set
the fine tuning at the center of its range. The adjustments
(located in a circle around the shaft) should be made in se-
quence from the highest to the lowest channel in the area.
Channel 13 adjustment is located at 12 o'clock, proceed in
a counter clockwise direction adjusting for best picture and
sound.
PICTURE TUBE SAFETY GLASS CLEANING
Remove 4 push-on type knobs from the front. Remove 4
metal screws holding knob escutcheons. Tilt the safety
glass out at the top and lift to remove.
SPECIAL ADJUSTMENTS
A. AGC
Observe the picture and advance the AGC control to a point
where the picture distorts or a buzz is heard in the sound.
Back off from this setting until the picture becomes stable
with no noise in the sound.
B. Fringe Lock
Turn the fringe lock control fully clockwise, then counter
clockwise approximately 1/4 turn. Adjust picture to lock in
with hold controls. If picture jitters, tears, etc. adjust
fringe lock counter clockwise until stable. Readjust hold
controls and check operation on all channels in the area.
C. Focus
The focus may be varied by means of a focus control. (For
location, see tube placement chart).
D. Width
The width may be varied by menas of a metallic sleeve lo-
cated between the yoke and the picture tube neck. Adjust
sleeve in or out of the yoke for a picture SLIGHTLY larger
than necessary to fill the screen.
HORIZONTAL OSCILLATOR FIELD ADJUSTMENTS
The horizontal oscillator coil is used as the horizontal hold
control. Adjust the horizontal hold until the picture syn-
chronizes horizontally. (For location, see tube placement
chart).
SOUND IF DETECTOR BUZZ ADJUSTMENT
To eliminate audio detector buzz, adjust the buzz control
for MINIMUM buzz and maximum sound. (For location,
see tube placement chart).
FUSES
One fuse is used for horizontal sweep circuit protection.
(For location, see tube placement chart).
CENTERING
Centering is accomplished mechanically by adjusting two
magnetic rings around the neck of the picture tube. Rotate
the two rings around the neck of the tube until the picture
is properly centered.
HOWARD W. SAMS & CO., INC.
The listing of any available replacement part herein does
not constitute in any case a recommendation, warranty or
guaranty by Howard W, Sams & Co., Inc., as to the quality
and suitability of such replacement part. The numbers of
these parts have been compiled from information furnished
to Howard W. Sams Si Co., Inc., by the manufacturers of
H389
• Indianapolis 5, Indiana
the particular type of replacement part listed. Repro-
duction or use, without express permission, of editorial or
pictorial content, in any manner, is prohibited. No patent
liability is assumed with respect to the use of the informa-
tion contained herein. © 1958 Howard W. Sams &Co., Inc.,
Indianapolis 5, Indiana . Printed in U.S. of America
o
o
m
70
DATE 3-58
SET 393 FOLDER 4