SA-EX310
NORMAL WAVEFORMS OF AMPLIFIER CIRCUIT AND LIKELY FAULTY BLOCKS
The HIC protection circuit functions if any cord at a speaker terminal is short-circuited or if the unit overheats because of improper
operation. At the same time, OVERLOAD scrolls across the FL display.
In this state, all keys remain in operative; if any key is pressed, SWITCH OFF POWER scrolls across the FL display.
If an overload occurs, immediately power off the unit and check the speaker connection, venting holes and cooling fans. After
fixing any faults, power on the unit again and check for proper operation.
If no defects are found, or if the unit remains overload after it is power on again, check the circuit for faults.
CIRCUIT BLOCKS
OVERLOAD DETECTION FUNCTION
Likely faulty block if the normal
TP CD player Tape deck AF oscillator waveform shown at the left is not
present.
C4 Power limiter block
Q551 to Q552 & area
S4
0.5msec 200mV* 1msec 500mV 1msec 1V
C5 Main amplifier block IC601 &
area IC602 & area
S5
0.5msec 5V* 1msec 10V 1msec 1V*
Measurement conditions. Volume control (VR501), Tremble
control (VR512) and Bass control (VR511) positions :
*Volume control position (VR501) for these test :
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