(A)
YES
Power is supplied to IC400[HD2]?
YES
Video display clock(IC615(7)) is supplied
to HD2? FIG.01
YES
END
FIG.01
VDP clock
FIG.02
Crystal 27MHz clock
NO
Check L400(1.8V), L401(3.3V) IC950(2)
(3.3V).
NO
Check X600
if there is sinusoidal 27MHz clock. FIG.02
3-17