Troubleshooting - Denon DHT-391XP Service Manual

TROUBLE SHOOTING
1. POWER
1.1. Power not turn on
Power not turn on.
Is the ON/STANDBY
indicator on the front panel
fl ashing red?
NO
Is the fuse blown?
NO
Does the power turn on
when the POWER switch is
turned off then back on?
YES
Check the primary ciruitry
parts including the POWER
switch(for poor contacts,
etc.), and replace any
defective parts.
1.2. Fuse is blown
Check for leaks or short
circuits in the primary side
parts,and replace any
defective parts.
Are there any incomplete
connections in the
YES
connectors connecting
between the various circuit
boards?
YES
Connect the connectors
property.
YES
Refer to Fuse is blown.
Is a DC 5V voltage being
NO
supplied from the MAIN B'd
to the microprocessors?
YES
Check the microprocessor
periphery circuitry and
replace any degective parts.
Fuse is blown
Check for short circuits in the
rectifi er diodes and circuitry of
the secondary side rectifying
circuits,and replace any
defective parts.
After repairing, also replace the fuse.
Is there a short circuit
NO
between the speaker
terminals and the ground?
NO
Check for damage in the
power amplifi er circuitry
parts and replace any
defective parts.
Is a DC5V voltage output
when the cord supplying the
NO
power from the MAIN B'd to
the microprocessor(BN43)
is unplugged?
YES
Check the circuitry and parts
from BN43 on the MAIN
B'd to the microprocessor
for damage and short-
circuits,and replace any
defective parts.
Check for short circuits in
the power stabilizer unit's
regulator output terminal and
the ground,and replace any
defective parts.
32
Correct the short
YES
circuit between the
speaker and ground.
Check the parts from
NO
IC45 to the primary
circuitry and replace
any defective parts.