DTM-5.9
OPERATION CHECK-2
SPEAKER PROTECT-2 (CURRENT DETECTION)
Test - _
Test - 1-00
[When]
1. Exchange power transistors (Q521 - Q524).
2. Exchange amplifier PC board ass'y (NAAF-9610).
<Note>
1. Do not check two channels at the same time.
2. Do not connect a dummy load to speaker terminal longer than 2 seconds.
[Procedure]
1. Press and hold down CD
button, then press On/Standby
button while the unit is powered on.
" Test - _ " is displayed only for 5 seconds.
2. Press DVD
button, while " Test - _ " is displayed.
The unit will be in the state of " Test - 1-00 ".
3. Set the master volume to minimum.
4. Connect the oscilloscope to SPEAKERS A Lch terminal. Refer to <Fig-1>
5. A square wave of 50 Hz is output from the oscillator, and this signal is input to the CD via the differentiation circuit.
6. Adjust for the output wave form of the SPEAKERS A Lch terminal to become 30 Vp-p
by master volume.
7. Connect the 2 ohms dummy load to the SPEAKERS A Lch terminal.
And check the speaker relays RL591 and RL592 are Not turned off
.
8. Connect the 0.5
ohms dummy load to the SPEAKERS A Lch terminal.
And check speaker relays RL591 and RL592 are Turned off
immediately and power indicator blinks.
Do not connect the load for 2 seconds or more when it doesn't turn off the relays.
9. Check Rch according to the same procedure.
10. Press On/
Standby
button.
11. Disconnect the AC power cord and oscilloscope.
Blinks
Clear
Standby
<Fig-1>
Dummy
load
Oscillator
Oscilloscope
30Vp-p
IN
GND
3.3k
10k
1SS133
x 6
3.3k
OUT
0.01 F
0.1 F
SPEAKERS A
L
R
50Hz
Rear panel
L
R
IN
CD
Differentiation
circuit
CD
IN
SPEAKERS A
L
R
L
R
L
R
w
w
w
.
x
i
a
o
y
u
1
6
3
.
c
o
m
Q
Q
3
7
6
3
1
5
1
5
0
9
9
2
8
9
4
2
9
8
T
E
L
1
3
9
4
2
2
9
6
5
1
3
9
9
2
8
9
4
2
9
8
0
5
1
5
1
3
6
7
3
Q
Q
TEL 13942296513 QQ 376315150 892498299
TEL 13942296513 QQ 376315150 892498299
http://www.xiaoyu163.com
http://www.xiaoyu163.com
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