Marantz 2240 - Suggestions for Trouble Shooting of Power Amplifier

Dea ats Bars Bae 4
8.
SUGGESTIONS
FOR
TROUBLE
SHOOTING
OF
POWER
AMPLIFIER
8.1 Excessive Line Consumption
a. Check for shorted rectifiers HOO7, also check C004 and C005.
b.
Check
for
shorted
transistors
H714
and
H715,
HOO1
and
HOO2,
or
check
HOO5
and
HOO6.
Check
for
open
control
R719.
Check
L004
for
short.
CAUTION:
BECAUSE
THE
DRIVER
AND
OUTPUT
STAGES
ARE
DIRECT
COUPLED
COMPONENTS
MAY
FAIL
AS
A
DIRECT
RESULT
OF
AN
INITIAL
COM-
PONENT
FAILURE.
IF
A
SHORTED
TRANSISTOR
OR
ZENER
DIODE
tS
FOUND,
OR
CONTROL
OR
BIAS
DIODE,
BE
SURE
TO
CHECK
THE
REMAINING
DRIVER
AND
OUTPUT
COMPONENTS
FOR
SHORT
OR
OPEN
CIRCUIT
BEFORE
RE-ENERGIZING
THE
AMPLIFIER.
8.2 No Line Consumption or Zero Bias
a.
Check
line
cord,
fuse,
transistors
HOO1,
HOO2.
HOO3
and
H004,
bias
diode
HOOS
and
HOO6.
b. Check for open rectifier HOO7, or open L004.
8.3 No DC Balance
a. Check R707 and Zener diodes H701 and H704.