AUDIO DEFECTS (I)
No sound.
Picture is OK.
Check 28 VDC at pin 9 of IC304. NO Check and replace components R341, D612,
S603.
NO
Audio signal at pins 1,5 of IC304 are OK. Check signals at pins 8, 10 of IC304. YES
No sound. Check and replace IC304.
NO
Audio signal at pins 28,29 of IC301 are OK. Check and replace R307, T301, R310, C326, YES
No sound. C332, R308, T305, R319.
NO
Audio signal at R150 Trap Filter is OK. Check and replace C230 and IC301. YES
No sound.
NO
Check and replace components R156, L105,
L106, C158, C159, C160, R150.
AUDIO DEFECTS (II)
YES
Check and replace R437 and R444.
Volume decreases to minimum.
Check 3.3 VDC at pin 80 of IC101.
NO
YES
Check and replace R436 and R445.
Volume increases to maximum.
Check 3.3 VDC at pin 78 of IC101.
NO
Volume Up/Down buttons change programme YES Check and replace R438 and R441.
numbers. Check 3.3 VDC at pin 1 of IC101.
NO
Check and replace R429, R317, C335.
YES
Pop sound is heard when switch off. Standby voltages of T307: B(0.6V), C(0V)
Operation voltages of T307: B(0.1V), C(15.5V)
NO
Check and replace R321, R318, T307.
Check and replace IC304. |
ACEC
