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X-HM81-K
5
6
7
8
5
6
7
8
A
B
C
D
E
F
5.2 PROTECTION CIRCUIT
If a protection circuit is activated then the unit enters Standby mode, the LED flashes in accordance with the activated
protection function, as shown in the table below.
The DC outputs from AMP_OUT_L and AMP_OUT_R are detected to avoid DC current surge to the speakers and excess
voltage at B+ (+33 V).
The protection circuit is activated when the signal at Pin 3 of IC601 changes from H to L.
If the DC, POWER, or PWM protection circuit is activated, operation of the unit will be locked.
The buttons that can be used to release operation lock are as follows:
Simultaneously press the "INPUT" and "
np
" (Tune Up, Skip Up) buttons on the front panel,
or simultaneously press the "STANDBY/ON" and "
g
" (STOP) buttons on the front panel.
After operation lock is released and the unit is then turned ON, the unit will perform the following:
• Count the number of activations of protection circuits
• Cancel flashing of the LED
Protection
LED ON
DC
POWER
AMP
OVER TEMP1
OVER TEMP2
PWM
BT (*)
100 msec
500 msec
100 msec
100 msec
100 msec
900 msec
100 msec
LED OFF
LED flashing time
Operation
Lock
900 msec
500 msec
100 msec
100 msec
100 msec
100 msec
100 msec
Lock
Lock
—
—
—
Lock
*X-HM81,XC-HM81 only
—
USB
100 msec
100 msec
—
Description of Each Function
• DC Protect
KTA1
268
Q635
R824
100K
B+
KDS4148U
D620
Q639
R867
K
T
C
3198
R827
10K
C731
MTZ22B
100N-K
Q636
KTC3198
R826
47K(1/4)
AMP_OUT_R
AMP_OUT_L
DC_PROTECT
MAIN_MICOM
IC601_3 pin
DC_PROTECT
3
D
MAIN ASSY
M3V3_SW
R602