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Yamaha AFC1 Service Manual page 59

Active field controller

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AFC1
2. < +5V system output voltage > (Circuit diagram CN5)
Procedure
Item Measured
(1)
Power supply switch ON
(2)
Check output voltage
No voltage output
Check input oscillation
(3)
waveform
Abnormal wave form
PFC circuit voltage
(4)
confirmation
Check wave form.
No voltage output
Abnormal wave form
Check PFC controller input
(5)
voltage
Check wave form.
No voltage output
Abnormal wave form
(6)
Check AC input voltage
No voltage output
4
Items Confirmed
AC input
Is DC+4.5V ~ +5.5V being input?
(With dummy load)
Measurement point: Circuit Drawing 2/2 "Point R"
Wave form measurement point: Circuit Drawing 2/2 "Point S"
(Refer to Fig. 9 for wave form sample. *9)
Is DC+370V ~ +400V being input?
Measurement point: Circuit Drawing 1/2 "Point A"
Wave form measurement point: Circuit Drawing 1/2 "Point B"
(Refer to Fig. 1 for wave form sample. *1)
Is DC+16V ~ +19V being input?
Measurement point: Circuit Drawing 1/2 "Point C"
Wave form measurement point: Circuit Drawing 1/2 "Point D"
(Refer to Fig. 2 for wave form sample. *2)
Is AC input voltage coming out?
Measurement point: Circuit Drawing 1/2 "Point E"
Voltage output
Normal wave form
Voltage output
Normal wave form
Voltage output
Normal wave form
Voltage output
Items Repaired
No abnormality
Replace the following:
IC10,Q6,D28,D30,D32
Replace the following:
IC1,IC2,Q3,Q4,R14,R16
Replace the following:
IC3,Q2,D3,ZD2,R4
Replace the following:
F1,Q1,ZD1,R3
Check insertion of AC
harness.

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