Akai ct1417 schematic

1AKAI CT 1417 UK

Electrical Adjustments

I. PLEASE READ BEFORE ATTEMPTING
SERVICE

1. Never disconnect any leads while receiver is
in operation.

2. Disconnect all power before attempting any
repairs.

3. Do not short any portion of the circuit while
power is on.

4. For safety reasons, all parts replaced should
be identical, (for parts and part numbers see
parts list).

5. Before alignment the set must be pre-heated
for 30 minutes or more and erase magnetism
thoroughly from CRT front chassis frame by
erase coil.

II. TEST EQUIPMENT

1. VIF Sweep Generator

2. SIF Sweep Generator

3. DC Power Supply (14V)

4. Oscilloscope

5. Digital Multi Meter

6. CRT Colour Analyzer

7. Demagentizing Coil

8. Philips Pattern Generator

9. Frequency Counter

III. TANK COIL ALIGNMENT
A. PREPARATION STEP (SEE FIG.2)

1. Connect OUTPUT lead of VIE Sweep
Generator between SA101 Pin 4 and ground.

2. Connect lead of FROM DET between TP106
(Pin 19 of IC101) and ground.

3. Apply a +14V DC to lead of D408.

4. Apply a AGC bias (approx 6.14V) to TP104.
Slowly adjust the AGC bias voltage until the
waveform is just before saturation.

Fig.1

Fig.2
B. ALIGNMENT STEP (SEE FIG.3)

1. Adjust T105 (TANK COIL) to obtain maximum

amplitude of response at 39.5MHz as in Fig.3.

Fig .3

IV. VIF ALIGNMENT (TUNER VIF COIL)
A. PREPARATION STEP (SEE FIG.4)

1. Connect the output of VIF Sweep Generator
between tuner test point TP and tuner case
with input level of 54dBpV.

2. Connect resistor (100 Ohm) between TP101
and TP102.

3. Connect the vertical input of the Oscilloscope
to the TP106 and ground.

4. Apply a +14V DC to lead of D408.

5. Apply a AGC bias (approx 6.14V) to TP104.

B. ALIGNMENT

1. Adjust AGC bias voltage slowly until the
waveform is just before saturation.

2. Adjust the vertical gain control of the Oscillo­scope until the waveform is 10 division on the
screen.

3. Adjust the ferrete core in the tuner until the
marker 39.5MHz has maximum amplitude and

35.07MHz has a difference of 1 division as
shown in Fig.4.

Fig. 4
V . AFC ALIGNMENT

A. PREPARATION STEP (SEE FIG.5)

1. Connect the signal output of Sweep/Marker
Generator to TUNER IF OUTPUT with a
signal level of 75dBpV.

2. Connect the vertical input terminal of
Oscilloscope to TP107.

3. Apply a +14V DC to lead of D408.

4. Apply a +6.14V DC to TP104.

Fig. 5
B. ALIGNMENT STEP

1. Adjust the AGC bias voltage slowly until
bottom portion of the waveform is just before
saturation.

3. Adjust T106 (AFC COIL) for a waveform as
shown in Fig.6.

Fig. 6

VI. SIF ALIGNMENT
A. PREPARATION STEP (SEE FIG.7)

1. Connect the output of SIF Sweep Generator
between TP106 and ground.

2. Connect the vertical input of Oscilloscope
between TP105 and ground.

3. Supply DC +14V to (+) lead of D408.

Fig. 7
B. ALIGNMENT STEP

1. Adjust the output of Sweep Generator until a
similar waveform is obtained (Fig.8).

2. Adjust T104 to obtain the marker 6.0MHz
rested on the horizontal line (Fig.8).
NOTE: Input Level = 90dB.

Fig. 8
VII. B+ ADJUSTMENT

1. Connect the digital voltmeter to TP401.

2. Adjust semi-fixed resistor VR901 until meter
reading DC 112.25V ± 0.25V.

VIII. HORIZONTAL CIRCUIT ADJUSTMENT

1. Connect the frequency counter to the heater
of the CRT and ground.

2. Set the TV set to AV mode without any input
signal.

3. Adjust the VR303 until the frequency is

15.625KHz ± 20Hz.

4. Set the TV set to TV mode and Receive
Monoscope Pattern.

5. Adjust VR302 to move the pattern horizontally
for center position.

IX.VERTICAL CIRCUIT ADJUSTMENT

1. Connect the frequency counter between V­deflection yoke and ground..

2. Set the TV to AV mode without any input
signal.

3. Adjust the V-hold VR304 until the counter
reads 44Hz ± 1 Hz

4. Set the TV set to TV mode and Receive
Monoscope Pattern.

5. Adjust V-SIZE (VR401) control to obtain a
normal picture.

X. FOCUS ADJUSTMENT

1. Set Contrast control to maximum position and
Brightness control to middle position.

2. Adjust Focus control (on the FBT) to obtain a
sharpest picture on the CRT.

XI. COLOUR DEMODULATOR ALIGNMENT,
DELAY LINE ALIGNMENT

1. Receive Philips Pattern.

2. Set Contrast control to minimum position.

3. Set Colour control to maximum position.

4. Connect Oscilloscope to TP301 (B-out).

5. Adjust CT301 to obtain the waveform as in Fig.9.

6. Adjust VR301 to obtain the waveform as in Fig.9.

7. Adjust T301 to obtain the waveform as in Fig.9.

XII. RF AGC

1. Connect a TV signal (60dB) from centre
system to the tuner.

2. A digital voltmeter is connected to the AGC
terminal of tuner (Pin 4).

3. Adjust VR101 until the voltmeter reads 4.8V.

XIII. ON SCREEN ADJUSTMENT (SEE FIG 10)

1. Receive the Monoscope Pattern.

2. Press the volume control.

3. Adjust OSD (VR601) so that the On Screen
Display is at center position.

Fig. 10
XIV. WHITE BALANCE ADJUSTMENT

1. Receive a Monoscope Pattern picture signal.

2. Turn the red, green and blue LOW LIGHT
(VR501, VR502, VR503) controls to middle
position and turn the DRIVE (VR504, VR505)
control to middle position.

3. Turn the Screen control on the FBT to
minimum position.

4. Set the Sub-Brightness (VR305) control to
middle position, then set the Contrast control
and Colour control to minimum position.

5. CN403 (Pin 1,2) with Join together.

6. Connect volt meter between (R508) and
ground, and adjust Brightness control to the
reading of DC 138V (±2V). If DC 138V cannot
be obtain, adjust the Sub-Brightness control
(VR305).

7. Slowly turn the Screen control clockwise to
the point where a horizontal line just illumi­nates.

8. Adjust VR501 to get a red horizontal line on
CRT.

9. Adjust VR502 to get a yellow horizontal line
on CRT.

10.Adjust VR503 to get a white horizontal line
on CRT.

11.Reset the Service Switch (S401) to “NOR­MAL” position and turn Brightness control to
middle position.

12.Adjust Drive (VR504, VR505) control to
obtain a uniform white picture.

XV. SUB-BRIGHTNESS ALIGNMENT

1. Receive a Monoscope Pattern.

2. Set controls as follows

BRIGHTNESS control........CENTER position.

CONTRAST control...........CENTER position.

COLOUR control...........CENTER position.

3. Adjust SUB-BRIGHTNESS (VR305) to get
NINE step of the grey scale just illuminate in
monoscope pattern as shown in Fig 11.

Fig. 11
XVI. COLOUR PURITY ADJUSTMENT

(SEE FIG.12)
BEFORE ALL ADJUSTMENT DESCRIBED
BELOW 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 (VR503,
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.

XVII. CONVERGENCE ADJUSTMENT

(SEE FIG.12)

1. Receive a crosshatch pattern.

2. Unfix the convergence magnet damper and
align red with blue dots at the center of the
screen by rotating (RB) static convergence
magnets.

3. Align Red/Blue with green dots at the center
of the screen by rotating (RB-G) static
convergence magnet.

CRT

Diagram

Remote Control

Diagram

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 convergence.

6. Fix the deflctlon yoke by wedges.

7. If purity error is found, follow “PURITY
ADJUSTMENT” instructions.

Fig. 12

Ear Jack Diagram

Main

Diagram

2AKAI CT 1417 UK