480 Chapter9
IF Section
Cal Oscillator (P/O A4 Assembly)
5. Vary the volume and listen for the variation in speaker output level.
Clipping is normal at the highest volume levels.
6. If the audio is not working correctly monitor the signal at A4U704
pin 3 with an oscilloscope. The signal should be 20 mV peak-to-peak
±25 percent (with +2.5 V of dc bias). If the signal measures outside
these limits, the fault is prior to the audio amplifier (block T).
7. If the signal is correct, troubleshoot the audio amplifier and speaker.
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