17
DHT-390XP
AVR-390
TROUBLE SHOOTING
1. POWER
1.1. Power not turn on
1.2. Fuse is blown
Power not turn on
Is the ON/STANDBY indica-
tor on the front panel flashing
red?
YES
Are there any incomplete
connections in the connec-
tors connecting between the
various circuit boards?
NO
Is there a short circuit
between the speaker termi-
nals and the ground?
YES
Correct the short circuit
between the speaker and
the ground.
YES NO
NO
Connect the connectors
properly.
Check for damage in the
power amplifier circuitry parts
and replace any defective
parts.
Is the fuse blown?
NO
Refer to Fuse is blown
YES
Does the power turn on when
the POWER switch is turned
off then back on?
NO
Is a DC 3.3V voltage being
supplied from the POWER
B’d (CP103 pins 3) to the
microprocessor?
NO
Is a DC 3.3V voltage output
when the cord supplying the
power from the SUPPLY B’d
to the microprocessor
(CP103) is unplugged?
NO
Check the parts from IC300
to the primary circuitry and
replace any defective parts.
YES YES YES
Check the primary circuitry
parts including the POWER
switch (for poor contacts,
etc.), and replace any defec-
tive parts.
Check the microprocessor
periphery circuitry and
replace any defective parts.
Check the circuitry and parts
from CP103 on the SUPPLY
B’d to the microprocessor for
damage and short-circuits,
and replace any defective
parts.
Fuse is blown
Check for leaks or short cir-
cuits in the primary side
parts, and replace any
defective parts.
Check for short circuits in
the rectifier diodes and cir-
cuitry of the secondary side
rectifying 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.
After repairing, also replace the fuse.
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