OPERATION CHECK-3
OUTPUT LEVEL & THERMAL DETECTION
TX-SR402/8240/HT-R420
U17
NAAF-7875
POWER AMPLIFIER PC BOARD
P6908
P6301
TH1
COM
P6301
TH1
COM
Front side
Output level detection
1. Set the unit to test mode
"
Test-3-2
"
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 VIDEO2 button, while the display of " Test - _ " has come out.
Unit will be in the state of "
Test-3-00
".
1-3. Repeat and press SPEAKERS B until the display of "
Test-3-2
" comes out.
2. Apply signal (sine wave 1kHz, -1.5dBV) to
MULTI CHANNEL (FL, FR, SL, SR, C)
terminal, each channel.
3. Check that FM STEREO indicator is display come out.
6. Press the STANDBY/ON button, and exit from test mode.
T e s t - _
T e s t - 3 - 0 0
T e s t - 3 - 0 2
T e s t - 3 - 0 2
FM STEREO
FM STEREO
Thermal detection
1. Set the unit to test mode
"
Test-3-2
"
Refer to the clause of "OUTPUT LEVEL DETECTION".
2. Connect the resistor 2.7kohms /1W between "HT1" and "COM" terminals of P6301.
3. Check that FM STEREO indicator is display come out.
6. Press the STANDBY/ON button, and exit from test mode.
T e s t - 3 - 0 2
FM STEREO
FM STEREO
2.7kohms
1W
<Check procedure by test mode>
The following is the procedure of checking detection operation of a microprocessor in false, by using test mode.