DTM-5.9
OPERATION CHECK-2
SPEAKER PROTECT-2 (CURRENT DETECTION)
T e s t - _
T e s t - 1 - 0 0
[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
CD
button, then press
On/Standby
/Standby
button while the unit is powered on.
"
Test - _
"
is displayed only for 5 seconds.
2. Press
DVD
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
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
Not turned off
.
8. Connect the
0.5
0.5
ohms dummy load to the SPEAKERS A Lch terminal.
And check speaker relays RL591 and RL592 are
Turned off
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/
On/Standby
Standby
button.
11. Disconnect the AC power cord and oscilloscope.
Blinks
C l e a r
Standby
<Fig-1>
Dummy
load
Oscilloscope
30Vp-p
IN
GND
3.3k
10k
1SS133
x 6
3.3k
OUT
0.01 F
0.1 F
SPEAKERS A
L
R
Rear panel
L
R
IN
CD
CD
IN
SPEAKERS A
L
R
L
R
L
R
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