Hitachi GCR-8480B User Manual page 5

B. Pick-Up doesn't move to the inner track.
Do the signals appear at IC501
pin 34 , ?
35
(Refer to Fig. B-1.)
YES
Does "H" output at IC201
pin ?
41
YES
Is the 2.5V at IC201 pin
YES
Do the signals appear in PN301
pin?
(Refer to Fig. B-2.)
YES
Check the PN301, and then
replace the Sled Motor.
CH1
PIN34
DA0
CH2
PIN35
DA1
Fig. B-1. DA0 and DA1 Signals
24
NO
NO
?
25
NO
Check IC501.
Check the pattern from
IC501 pin to IC201
107
pin .
41
NO
Replace IC102.
Replace IC201.
CH1 TP4
CH2 TP5
CH3 TP6
CH4 TP7
(/A)
(A)
(/B)
(B)
Fig. B-2. TP4, TP5, TP6 and TP7 Signals