Switching Regulator (Aps-179) Adjustment; Oscillating Frequency Adjustment; Voltage Adjustment With Minimum Load - Sony PFM-42B2 Service Manual

2-7. Switching Regulator (APS-179) Adjustment

Preparation : Remove the switching regulator from the main unit.

2-7-1. Oscillating Frequency Adjustment

1. Short-circuit pins-3 and -4 of PH101, PH-107, PH-111 and PH-902 respectively.
2. Short-circuit gate and source of Q302 and Q308.
3. Apply DC 22 V to C122 and adjust the oscillating frequency as listed below.
Between gate and source
Q108
Q113
Q154
Q504
Q704

2-7-2. Voltage Adjustment with Minimum Load

Load of each output
Output Pin No.
CN23 3pin
Vcc (5 V)
CN23 8pin
Vs
CN23 1pin
Va
CN9002 1pin
St-by 5 V
CN6 1
Vpr2
CN9003 1pin
26 V
CN9001 7pin
A13.5 V
CN9002 6pin
D3.3 V
CN9002 !/pin
D5 V
CN9001 3pin
A6 V
Audio +12 V CN9004 8pin
Audio _12 V CN9004 5pin
PFM-42B2/42B2E
ADJ Specification
83k ± 0.5 kHz
RV101
84k ± 0.5 kHz
RV102
73k ± 0.5 kHz
RV150
67k ± 0.5 kHz
RV901
65k ± 0.5 kHz
RV950
Minimum load Maximum load
2.0A 6.0A
0.5A 4.0A
0.1A 3.5A
0.1A 0.3A
0A 0.05A
0.1A 1.0A
0.1A 2.0A
0A 1.5A
0A 1.8A
0A 1.5A
0A 0.71A
0A 0.71A
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