RCA Victor TRK-12, Руководство пользователя

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(8.75 to approximately 14 m c). T he RF interference can
thus be picked out and identified.
(T o gain experience in recognising the visual aspect of
various forms of interference, it is possible to produce the
interference locally and study the results. Sparking motors
and similar devices can be operated near the television re*
ceiver. A test oscillator can be coupled to the receiver input
while a television program is being received. Tune the oscil'
lator to the pictur.e carrier frequency and then shift it up
several megacycles to produce a range of beat frequencies
with the picture carrier. T he oscillator output can be in*
creased and decreased, and modulation can be turned on and
off to note the effects.)
21. Failure to operate when installed in cabinet-
fa) Check for grid shorts in '52 and. 'S3 tubes.
(b ) Check for bent'over pins on the octal plug from video
chassis to SPU
_________________ PAGE 2 7 1 - C
TRK9, TRK90, TRKI2, TRKI20
22. Interference from harmonics of horizontal deflecting
circuits. In lst'production 9'inch and 12'inch receivers,
harmonics of the horizontal deflecting frequency (15.75 kc)
may cause interference on nearby radio receivers. In this
case, install the following:
(1 ) A shielded yoke (RCA Stock No. 9857N ). This has
a metal pigtail at plug end of cable for grounding
under one of the mounting screws on the horizontal
. output transformer. Unshielded yokes./ do not have
this pigtail.
(2 ) A tube shield (RCA Stock No. 12181) on the 5V4G
horizontal damper tube. Ground the tube shield to
chassis with a pigtail.
(3 ) Remove the external ground .connection from the
television receiver.
TRK-9, TRK-12, TRK-120 for 105-125 Volts—50-60 Cycle Power Supply
General differences are as follows:
Chassis KC-4B, KC-4C, KC-4J
1. Horizontal Damping tube, formerly RCA'5V4G,
changed to RCA'25Z6 and socket* wiring revised.
2. TRK'9, T R K '12 only: Capacitor 0 6 1 not connected.
Its function is performed by an added capacitor C l 17 (4 mfd.
— 450 volts).
Chassis KK-7D, KK-7E, KK-7J
1. Capacitors CM 18 (80 mfd.) and (M 19 (10 mfd.) added
in parallel with (M 10.
2. Capacitor 0 1 2 8 —'T R K 'l 20 or (>120—TR K '9, TRK'
12 (Q.2'5 mfd.) added in parallel 'with resistor R'166—
T R K '120 without D.C. Restorer, or R'126— TRK'9, TR K '
12, TRK* 120 with D.C. Restorer.
3. Capacitors CM 13 (0.03 mfd.) and (M 14 (0.03 mfd.)
changed to (M 21 (0.1 mfd.) and 0 1 2 2 (0.1 mfd.).
4. Power transformer (T '5 ) changed to (T '8 ) having a
25v. heater winding to supply the RCA'25Z6 horizontal
damping tube.
5. H igh voltage power transformer (T '6 ) changed to
(T '9 ).
6. Resistor R'165 is added (T R K '120 only).
7. Inductance' L'50 is 100 ohms in these models.
8. An RCA'5T4 is used in these models as low voltage
rectifier.
In addition Kinescope shielding is provided as follows:
1. A metallic conical section is installed in the cabinet to
shield the Kinescope bulb.
2. A double metallic cylindrical section is installed with the
deflecting yoke' mounting assembly to shield the deflecting
yoke proper. T he accompanying illustration shows its as'
sembly.
C A U TIO N : The conical shield is of the proper size to
permit installing the 12AP4/1803'P4 Kinescope, with its pro'
tective cardboard, sleeve. T he latter should never-be removed.
T o prevent Kinescope breakage, when installing a Kine'
scope, the deflecting yoke and shield, assembly must be in
place. T o prevent breakage of Kinescope when removing the
deflecting yoke and shield assembly the Kinescope must be
removed first.
Replacing o r orienting deflecting yoke:
1. Remove Kinescope.
2. Loosen yoke support bracket wing nuts and remove
complete yoke and shield assembly.
3. Remove outer shield. Loosen yoke dam p screws t a
permit removal or orientation of -yoke. If it is necessary to
orient yoke, pull yoke out so it extends about one inch.
Tighten screws just enough to hold yoke but not too tight
as it may be necessary to turn it in this extended position.
Replace the inner shield and yoke in the yoke mounting
brackets.
4. Replace Kinescope and protective glass cover.
5. Move the inner shield and yoke assembly vertically
until yoke is gently touching Kinescope bulb. Tighten yoke
bracket wing nuts.
6. Rotate yoke carefully with one hand to orient raster or
picture.
7. Remove Kinescope.
8. Remove carefully (so as n o t to disturb yoke adjust'
ment) the inner shield and yoke assembly. Place the latter on
a flat surface with the extended yoke end flush to surface.
Press inner shield gently down until yoke edge is flush with
inner shield edge. Tighten yoke clamp screws evenly by first
pulling one up and then the other.
9. Assemble outer shield to inner shield and yoke assent'
bly so bottoms of shields are flush.
10. Replace complete shield and yoke assembly in the yoke
support bracket.
11. Replace Kinescope and tighten protective glass cover.
12. Push gently complete assembly up flush against the
Kinescope bulb. Tighten wing nuts.
IM PO RTA N T: 1. The hole in the conical metallic shield
must line up with the hole in the protective sleeve to permit
connection of the second anode cable.
2. Do not jar or drop the shields and keep away from the
loudspeaker field coil to prevent magnetization.