I found the manual to be clear concise and complete. It was of immense assistance when removing the unit as the unit was over 22 years old and the wiring diagram was unobtainable from the manufacturer. The exploded drawings were clear as were the instructions and labels.
Very pleased with the quality of the scan. No complaints whatsoever.
Text excerpt from page 15 (click to view)
9. TECHNICAL DESCRIPTION
The Peak Detector (explanation about Front L CH) 1) First stage of QG01 <NJM4558DD> (on PG01) functions for comparator. 2) The input signal voltage at JE01 <INPUT Front L> (on PE01) is sent to the 3 pin of QG01 by way of CG01 (on PG01) and RG01 (on PG01), part of Speaker Output voltage is sent to the 2 pin of QG01 by way of RN55 (on PT01), CG05 (on PG01) and RG06 (on PG01). 3) The 2 pin voltage is same to the 3 pin until about 1.5V input voltage at JE01. Therefor the 1 pin of QG01 output voltage is 0V. 4) When input voltage at JE01 is more than 1.5V, Speaker Output voltage reaches at clipping level and the 2 pin voltage is different from the 3 pin. 5) Then some voltage appears at the 1 pin of QG01. 6) Negative voltage is taken out by DG01 (on PG01) and DG02 (on PG01), then QG02 <2SA608SP/ETC> (on PG01) becomes ON and PEAK LED turns on. Notice: The PEAK LED turns on little in usual operation, This turns on when input voltage at JE01 becomes 1.5V over and Speaker Output voltage is more than 36V.