Alignment Procedure - Commodore 1901 Service Manual

ALIGNMENT PROCEDURE
Setting a) Connect AC power and assure that in within the operating rates.
b) Connect a correctly adjusted color computer to the rear input connector and set the slide switch for the
computer being used.
A) A2 Voltage Adjustment
1) set brightness, contrast, intensity control min.
2) measure the DC voltage (A2) of cadiodes at DP10 and chassis ground.
3) adjust PP01 to 114 voltage ± 1%
B) Horizontal Frequency Adjustment
1 j Brightness : Background just back
Contrast ; 50%
Intensity Maximum
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)
Picture tube must be facing East direction
3) Set should be carried out in the same magnetic field as its final destination (Equatorial or Southern Magnetic
field)
4) Test point is shorted to ground
5) Adjusted PL02 until the Picture is close to synchronization or the free running horizontal frequency
= 15626 Hz ±50 Hz.
C) Vertical Frequency Adjustment
1) Inject a 46 Hz signal into TP
2) Adjust PF01 for the black bar on the raster to be almost stationary or vertical frequency = 46 Hz ± 0.2 Hz.
D) Horizontal and Vertical Shifting Adjustment.
1) Adjust PL01 until picture is centralised at PAL composite mode.
2) Adjust PV07 until picture is centralised at RGBI mode.
E) Vertical Amplitude
Adjust PF02 such that the 3 reference lines on the top of the screen disappear.
F) Intensity Control
Adjust PV04 for intensity control (in this Alignment Procedure Intensity Control must be set to maximum)
G) Focus
1) Display a pattern of characters on the screen
2) Adjust focus knob on the flyback transformer UL02 for the best focus at screen edge on the diagonal axis.
H) Geometrical Distortion
1) Set up a crosshatch pattern on the screen
2} Pin cushion correction.
Align PE01 for the extreme vertical lines on the right and left side of screen.
adjust ^
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