Pioneer X-EM11V Service Manual page 17

5
A
NG
Has the protection circuit for TDA7491HV
(IC302) of the POWER amplifier been activated
(is the signal level from Pin 28 high)?
Yes
Has overvoltage protection been activated for
TDA7491HV (IC302) of the POWER amplifier ?
(Is the voltage at Pins 6, 7, 12, and 13 20 V or
higher?)
Yes
Failure in power supply (Because of an error in
SMPS Assy, the supply voltage, which should be
+13 V, becomes 20 V or higher.) In effect,
there is possibility that other ICs are damaged.
Check if the voltage at Pins 1 and 2 of CN1102 on the
SMPS Assy and of CN402 on the MAIN Assy is 13 V.
OK
Replace the MAIN Assy.
5
6
No
TDA7491HV (IC302) of the POWER amplifier is
defective. Replace the MAIN Assy.
Has undervoltage protection been activated for
No
TDA7491HV (IC302) of the POWER amplifier?
(Is the voltage at Pins 6, 7, 12, and 13 4 V or
lower?)
Yes
Failure in power supply (Because of an error in
SMPS Assy or damage on L6, the supply voltage,
which should be +13 V, becomes 4V or lower.)
NG
The SMPS Assy or the connection cable may be
defective and require replacement.
Has overcurrent protection been activated for
TDA7491HV (IC302) of the POWER amplifier?
(Is the voltage at Pins 2, 3, 8, and 9 [for Ch. R]
or 10, 11, 16, and 17 [for Ch. L] 0 V
[short-circuited]?)
Yes
Check the periphery of the speaker terminals.
OK
Replace the MAIN Assy.
X-EM21V
6
7
No
Has thermal protection been activated for
No
TDA7491HV (IC302) of the POWER amplifier?
Can the unit restart after this IC is cooled down
using a point cooler?
Yes
IC302 is defective. Replace the MAIN Assy.
7
8
A
B
C
D
E
F
17
8