Theory Of Operation - Bose Lifestyle PS 28 Troubleshooting Manual

PS18/28/35 Troubleshooting Guide

Theory of Operation

3.3 Clip Detect Circuit
The satellite clip detect circuit consists of diodes D401, D101, D301 and transistors Q3 and Q4
(upper left section of sheet 2). Q4 and Q3 are normally OFF. At high volume levels, if any one of
the satellite amplifier outputs comes within 2 volts of the positive power supply rail, Q4 and Q3
turn ON and signal the DSP board through SAT_CLIP that compression is needed.
Similarly, the bass clip detect circuit consists of transistors Q5 and Q2. Note: this circuit has been
deleted in later production, due to the DSP board making its own determination as to whether a
clip condition exists.
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