Akai CT2872 Schematic
AKAI CT-2862 UNT
Adjustments
Test Equipment: VIF Sweep Generator; SIF
Sweep Generator; Colour Bar/Dot/Cross Hatch
Generator; DC Power Supply (14V); Oscilloscope; Vacuum Tube Voltmeter; Volt Ohmmeter;
High Voltage Meter; Ampere Meter (0.5 Class,
DC 3mA Max.). Demagnetizing Coil; Philips
Pattern Generator; Frequency Counter;
Continuous Waveform Generator.
TV SECTION (See Table Opposite)
15. FM SOUND LEVEL ALIGNMENT
1. Receive a colour bar signal with Nicam and
FM 1KHz sound.
2. Connect the voltmeter to speaker ‘+‘ and
‘GND’.
3. Select the TV set to NICAM mode and set the
volume level to 0.5W.
4. Change to FM mode and Adjust the VR1101
until the reading same as NICAM mode±1dB.
16. PIN CUSHION ADJUSTMENT
1. Receive the Philips Pattern signal.
2. Adjust the H.SIZE control (755) until
overscan.
3. Adjust the TRAPEZIUM control (756) until the
pattern minimum distortion.
4. Adjust the EASTWEST control (757) until the
Pin Cushion minimum distortion.
5. Adjust the TOP LINE control (758) until the
vertical line minimum distortion.
Fig. 1
Fig. 1a
17. COLOUR PURITY ADJUSTMENT
(SEE FIG.5)
BEFORE ALL ADJUSTMENT DESCRIBED
ARE ATTEMPTED, V-HOLD, H-HOLD, V-HIGH,
B+ VOLTAGE AND FOCUSING ADJUSTMENT
MUST BE COMPLETED.
1. Place the TV receiver facing NORTH or
SOUTH.
2. Plug in TV receiver and turn in on.
3. Operate the TV receiver over 30 minutes.
4. Fully degauss the TV receiver by using an
external degaussing coil.
5. Receive a crosshatch pattern and adjust the
static convergence, control roughly.
6. Loosen the clamp screw of the deflection
yoke and pull the deflection yoke towards you.
7. Fully turn the red and blue Drive (VR504,
VR505) controls counter-clockwise.
8. Adjust the purity magnets so that green field
is obtained at the center of the screen.
9. Slowly push the deflection yoke towards bell
of CRT and set it where a uniform green field
is obtained.
10.Tighten the clamp screw of the deflection
yoke.
18. CONVERGENCE ADJUSTMENT
(SEE FIG.5)
1. Receive a dotted pattern.
2. Unfix the convergence magnet damper and
align red with blue dots at the center of the
screen by rotating (RB) static conver gence
magnets.
3. Align Red/Blue with green dots at the center
of the screen by rotating (RB-G) static
convergence magnet.
4. Fix the convergence magnets by turning the
damper.
5. Remove the DY wedges and slightly tilt the
deflection yoke horizontally and vertically to
obtain the good overall covergence.
6. Fix the deflection yoke by wedges.
7. If purity error is found, follow “PURITY
ADJUSTMENT” instructions.
Fig. 2
Fig. 4
Fig. 6
Fig. 3
Fig. 5
Fig. 7
AKAI CT-2862 UNT
AV Switching Diagram
Pin Cushion
Diagram
Waveforms
Front LED
Diagram
Text Diagram
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