Current Detection Protectors - Onkyo HT-R820THX Service Manual

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OPERATION CHECK-2

CURRENT DETECTION PROTECTORS

<Note1>
In test mode " Test 4-32 ", the pulse waveform is outputted from DSP IC on the pre-amplifier section, and it is inputted into
a power amplifier circuit. Refer to <Fig-1>.
Therefore an external input is unnecessary in check.
<Note2>
Don't connect speakers or any load.
Don't short speaker terminals.
Don't check two or more channels simultaneously.
1. Set the unit to test mode " Test-4-00 " .
1-1. Press and the hold down the CD button , then press the STANDBY/ON button when the unit is Power On.
1-2. Press the VIDEO 3 button, while the " Test - _ " is shown.
Unit will be in the state of " Test-4-00 ".
2. Repeat and press SPEAKERS B to the " Test-4-32 " is shown.
3. Connect the road resistor 3 ohms to the speaker terminal.
4. Check that the " P rot ec t " is not shown.
5. Connect the road resistor 1.5 ohms to the speaker terminal.
TE 6. Check that the " Protec t " is shown, and speaker relays are turn off.
L 13942296513
7. Check about the FL, FR, C, SL, SR and SB channel one by one.
8. Press the STANDBY/ON to power Off. (Exit the test mode)
<Fig-1>
The output waveform from DSP IC in the test mode 4-32.
2 ms 2 ms
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T e s t - _
blinks
T e s t - 4 - 0 0
T e s t - 4 - 3 2
P r o te c t
20 ms
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2 9
8
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3 6 7 1 3 1 5
Details of TEST MODE 4-32
TEST MODE DSP
output ch.
4-32
ALL
MASTER VOLUME = 54
co
.
HT-R820THX
9 4 2 8
0 5 8 2 9 9 4 2 8
DSP
output voltage
Max.
m
9 9
9 9