Sharp VT-3418X - Page 13

VT-341 8X
VT-5118X
DEFLECTION LOOP ADJUSTMENT (Continued)
Adjusting Conditions
Adjusting Procedures
5. Vertical Centering Adjustment
l During the’adjustment, keep the unit facing the east.
Vertical Center Adjust switch
This adjustment should be performed after
the purity and convergence adjustments.
“MONOSCOPE PATTERN” signal.
1. Adjust 5501 so that the picture’s vertical center is
idential to CRT geometrical vertical center.
ADJUSTMENT OF THE IF CIRCUIT
Adjustment of the RF AGC
Adjustment of the AFT
Test point
TP201 @I (GND)
TP201 0 (Video Output)
Adjusting point
I
VROOl (AGC control)
I
1. Receive the colour bar signal (input field
strength: 80 dBp).
2. Observe the video output terminal waveform
on the oscilloscope. Adjust VROOl (AGC control)
in the IF pack until the noise disappears from
the oscilloscope screen and the waveform
nearly comes into sync.
Just before shrinking
Figure 1.
Measuring
Oscilloscope
instrument Signal generator
Mode
I
EE
Input signal
PIF frequency uniwave
Colour bar signal (70 dBp)
Test point
I
TP201 @ (GND)
TP201 @ (Video Output)
Adjusting point
I
TOO2 (AFT coil)
Specification -
I
1. Receive the colour bar signal (input field
strength: 70 dBp).
2. Using the signal generator, feed the PIF
frequency (38.9 MHz) signal (sinewave) to the
tuner IF output terminal.
3. Set the tuning switch to the VHF or UHF
position. Keep the tuning button (+) or (-)
depressed until the beating on the oscilloscope
screen be minimum.
4. Set the tuning switch on the normal position.
Adjust TOO2 (AFT coil) so that beating on the
oscilloscope screen be minimum.
I
Figure 2. IF Pack
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