Focus Poor - NEC N9902-1 Service Manual

8. FOCUS POOR

FOCUS POOR
YES
CHECK
T302 14PIN H-DYNAMIC
PARABOLA WAVEFORM 550Vpp,
V-DYNAMIC PARABOLA
WAVEFORM 180Vpp
NO
CHECK
T303 H AND V PARABOLA
WAVEFORM
NO
CHECK
C323 H-PARABOLA
WAVEFORM 29Vpp
NO
CHECK
Q303, Q304 EMITTER
H-PARABOLA
32-Vpp
YES
CHECK
Q301, Q317 COLLECT
H-PARABOLA
5-Vpp
YES
GO TO
FACTORY MODE,
CHOICE H-FOCUS ICON, ADJUST
TO 80~100%, CHECK U301
10PIN FOCUS 3.8Vpp
NO
TROUBLE IN U301
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ADJUST
T302 STATIC FOCUS VR AND
YES
DYNAMIC FOCUS VR
T303, Q305, R360, R32H,
NO
V-PARABOLA
YES
NO
NO
25
1. CHECK STATIC FOCUS AND
DYNAMIC FOCUS VR LINE TO
NO
CRT SOCKET
2. CRT SOCKET OR CRT POOR
TROUBLE IN
R331, R339, C322, C324,
C320
TROUBLE IN T303
TROUBLE IN
Q302, Q303, Q304, Q338
TROUBLE IN
Q301, Q307