STR-DN860/DN1060
29
SECTION 5
TROUBLESHOOTING
Flow of Repair (when sound is not outputted) (1/5)
NG
NG
START
Check that the “PROTECT” is
not displayed on the
fluorescent indicator tube.
NG NG
OK
NG
NG
NG
OK OK
OK
OK
OK
NG
OK
OK
OK
Check that voltage of the following
pin is 3.3 V.
MB-1409 board:
IC3002 pin 76 (PROTECTOR)
Check that the defect is not improved,
even if you do the following works.
1. Short - circuit the both ends of the
C3011 on the MB-1409 board.
2. Perform the “SHIPMENT MODE”
(refer to page 20 on the original
service manual).
Check the IC3002 on the MB-1409
board and the surrounding circuit,
and exchange the defective parts.
Check the surrounding circuit of
power transistor (example: Q1600 on
the MAIN board) and the surrounding
circuit of power amplifier circuit
(example: FL on the MAIN board),
and exchange the defective parts.
– Continued on
page 30 –
Check that the following fuses are
not damaged.
MAIN board: F910, F911
STANDBY board: F901
Check that the power transistor
(example: Q1600 on the MAIN board),
the power amplifier and the surrounding
circuit are not defect.
Check that the surrounding circuit of
current detect (example: Q1600 and
Q1601 on the MAIN board) is not defect.
Check the surrounding circuit of
protector (example: Q1604 on the MAIN
board), and exchange the defective
parts.
Check that between the +59 V line/–59 V (±B)
line and the ground does not short circuit.
Check the surrounding circuit of power transistor
(example: Q1600 on the MAIN board) and the
surrounding circuit of power amplifier IC
(example: PWR AMP on the MAIN board), and
exchange the defective parts.
Check the surrounding circuit, and exchange the
defective parts.
Measure the power transistor (example: Q1600
on the MAIN board) with a tester, and check the
following things.
1. Check that the circuit does not short-circuit.
2. Check that resistance is normal.
Check the surrounding circuit, and exchange the
defective parts.
Measure the power amplifier circuit
(example: FL on the MAIN board) with a
tester, and check the following things.
1. Check that between the power supply
line and the ground does not
short-circuit.
2. Check that resistance is normal.
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