Trouble Shooting; Power Not Turn On; Fuse Is Blown - Denon AVR-1909 Service Manual

TROUBLE SHOOTING

1. POWER

1.1. Power not turn on

Power not turn on
Are there any incomplete con-
Is the ON/STANDBY indicator
YES nections in the connectors con-
on the front panel flashing
necting between the various
red?
circuit boards?
YES
Connect the connectors prop-
NO
erly.
NO
Is the fuse blown? Refer to Fuse is blown
YES
Is a DC 6V voltage being sup-
Does the power turn on when
plied from the POWER UNIT
NO
the POWER switch is turned
(CN505 pins 4, 5) to the micro-
off then back on?
processor?
YES YES
Check the primary circuitry
parts including the POWER Check the microprocessor
switch (for poor contacts, periphery circuitry and replace
etc.), and replace any defec- any defective parts.
tive parts.

1.2. Fuse is blown

Fuse is blown
Check for short circuits in the
Check for leaks or short cir-
rectifier diodes and circuitry of
cuits in the primary side parts,
the secondary side rectifying
and replace any defective
circuits, and replace any defec-
parts.
tive parts.
After repairing, also replace the fuse.
Is there a short circuit between Correct the
NO YES
the speaker terminals and the between the speaker and the
ground? ground.
NO
Check for damage in the power
amplifier circuitry parts and
replace any defective parts.
Is a DC 6V voltage output when
the cord supplying the power Check the parts from IC501 to
NO NO
from the SUPPLY UNIT to the the primary
microprocessor (CP514) is replace any defective parts.
unplugged?
YES
Check the circuitry and parts
from CP514 on the SUPPLY
UNIT to the microprocessor for
damage and short-circuits, and
replace any defective parts.
Check for short circuits in the
power stabilizer unit's regula-
tor output terminal and the
ground, and replace any defec-
tive parts.
AVR-1909/789, AVC-1909
short circuit
YES
NO
NO
YES
NO
circuitry and
YES
23
NO YES
YES NO
NO NO
YES YES