Pioneer cx 692 service manual

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2 C X-692 Q104 PICKUP UNIT IC103 TA1254AF 45LDO1 MDI1 44GND 7 VCC 8 VPS IC101 3 4 2 1IM CP OUT PICKUP UNIT Fig. 1 Fig. 2 1. Circuit Description 1.1 APC circuit - APC (Automatic Power Control) circuit [Fig. 1 CD and Fig. 2 DVD] Since the optical output of laser beam diodes carries a large negatived temperature characteristic, necessary optical power cannot be acquired when driven at a lower current level. The APC circuit is a circuit to control the current levels so that the output of the monitor diode may become constant. By measuring the voltage occurring between the LD and the drive transistor, the LD current can be found out and such current value should be within ±20% of the value indicated on the pickup unit flexible P.C. board when handling the CD and should be 50mA or less when handling the DVD.

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C X-692 3 1.2 FOCUS-JUMPING CIRCUIT Focus-jumping function is a function conforming to single side 2-layer discs or double-side 2 layer discs. Fig. 3 below shows the basic movement sequence. Viewing through the objective lens, the layer on this side is called Layer 0 (L0) and the layer on the far side is called the Layer 1 (L1). Objective lens RF FE Focus standby level Focus ON Vref GNDVref A(Fig.4) TEST00 B(Fig.4)IO0 L0=L1 L1=L0 L0 L1 L0L1L0 (Layer1) L1 (Layer0) L0L1 L0 ABCD E A BC DE Fig. 3