Pioneer cx 3057 service manual
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Extracted text from pioneer cx 3057 service manual (Ocr-read)
Page 1
21 234 1234 F E D CB A CX-3057 1. CIRCUIT DESCRIPTIONS Recently, most CD LSI's have included DAC, RF amplifier and other peripheral circuits, as well as the core circuit DSP. This series of mechanisms employ a multi-task LSI UPD63760GJ, which has CD-ROM decoder and MP3 decoder in addition to the CD block as shown in the Fig.1.0.1. This enables to reproduce a CD-ROM where MP3 data is recorded. Plus, in this lineup, there are WMA supported models available where WMA decoder UPD61002GC is added. CXK5660 --- WMA non-supported CXK5661 --- WMA supported Fig.1.0.1 Block diagram of CD LSI UPD63760GJ RF amplifier CD-ROM decoder BMC Digital servo EFM Signal processor MP3 decoder DAC DRAM Microcomputer A-F Drive output UPD63760GJ Audio output
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3 56 78 F E D CB A 56 78 CX-3057 1.1 PREAMPLIFIER BLOCK (UPD63760GJ: IC201) In the preamplifier block, the pickup output signals are processed to generate signals that are used for the next-stage blocks: the servo block, demodulator, and control. After I/V-converted by the preamplifier with built-in photo detectors (inside the pickup), the signals are applied to the preamplifier block in the CD LSI UPD63760GJ (IC201). After added by the RF amplifier in this block, these signals are used to produce necessary signals such as RF, FE, TE, and TE zero-cross signals. The CD LSI employs a single power supply system of + 3.3V. Therefore, the REFO (1.65V) is used as the reference volt- age both for this CD LSI and the pickup. The LSI produces the REFO signal by using the REFOUT via the buffer amplifi- er and outputs from the pin 131. All the measurements should be made based on this REFO. Caution: Be careful not to short the REFO and GRD when measuring. 1.1.1 APC (Automatic Power Control) A laser diode has extremely negative temperature characteristics in optical output at constant-current drive. To keep the output constant, the LD current is controlled by monitor diodes. This is called the APC circuit. The LD current is calculated at about 30mA, which is the voltage between LD1 and V3R3D divided by 7.5 (ohms). Fig. 1.1.1 APC 6.5 k + - 1 k 100 k + - 6.5 k 100 k + - 110 k 1 k REG 1.25 V Vref 3 p 142 143 140PD PNLDREGO LD UPD63760GJ 141 + + 100 p 10 µ 0.1 µ 5 7 15 5 7 15 14 14 PICKUP UNIT(SERVICE)(P10) CD CORE UNIT(S10MP3) 1.5 x 52SB1132 1SS355 100 / 16 LD- LD+MD MDVR LDSAPN