Pioneer cx 3078 service manual

This is the 26 pages manual for pioneer cx 3078 service manual.
Read or download the pdf for free. If you want to contribute, please upload pdfs to audioservicemanuals.wetransfer.com.

Page: 1 / 26
pioneer cx 3078 service manual

Extracted text from pioneer cx 3078 service manual (Ocr-read)

Page 1

CX-3078 2 1234 1234 C D F A B E + ++ +5V +5V MD 0.25V 0.5V 0.59V 0.18V 0.22VCDLD0CDLD1CN1101 24 5 26 7 LPCO2 PU unit LDONCD LDPOWER LDONDVDLPC23.9Ω3.9Ω3.9Ω3.9Ω – + 0.17V0.25V 0.18V +5V DVDLD0DVDLD1 LPCO1 LPC13.9Ω3.9Ω3.9Ω3.9Ω – + – + – + Reg. 78LD CD LDDVD LD 78MD 65LD 65MD 1 Front End Part (MN35103UB, MN35104UB:IC1501) MN35103UB and MN35104UB are 1-chip LSI for DVD-Player. The connection of this LSI to the Driver IC, SDRAM, Flash-ROM, Audio-DAC, etc. can configure the DVD-Player System. This LSI contains Front End (SODC/FE) that performs RF signal /Servo /Decode processings, Back End (AV decoder/BE) that performs the video decode processing such as MPEG1/MPEG2/JPEG and audio decode processing such as DVD-Audio/AC-3/DTS/MP3, and the system controller (Siscon) for controlling the system. Front End part realizes the arithmetic processing of optical head signal and RF signal processing, the digital signal processing for DVD-ROM reproduction that conforms to DVD standards (16-8 Demodulation, Error correction), the digital signal processing for CD-DA/CD-ROM (Error correction), AV decoder transmission, servo control, spindle motor control and seek control. Please take note that, since (FEP) and (SODC) with DVD mecha-module (MS3) of CX-3016 are integrated into one chip at MN35103UB and MN35104UB, the waveforms of servo system on the front end which had previously appeared at MS3, i.e., the waveforms of FE, TE and AS, cannot be seen anymore. 1.1 Analog Block (MN35103UB, MN35104UB:IC1501) The analog block for IC1501 generates the servo signals including focus and tracking, processes addition of RF signals, and controls the laser power of pickup. The servo system contains focus operation amp, focus offset adjustment circuit, 3-beam tracking operation amp, phase difference tracking detection circuit, tracking offset adjustment circuit, TE2 value-making circuit. Also, RF signal processing system contains the functions of AGC and equalizer. 1.1.1 APC Circuit The optical output for the laser diode (LD) has large minus temperature characteristics. Therefore, the constant optical output cannot be obtained when LD is driven by the constant current. APC circuit controls the electric current so as to provide constant output at the monitor diode (MD). MN35103UB and MN35104UB contain two types of APC circuits, one for DVD and another for CD. The LD electric current for DVD (CD) can be obtained by dividing the voltage measurements between DVDLD1 (CDLD1) and 5V by 15.6 (3.9 4= 15.6 ). For DVD (CD), the results are approx. 26mA (44mA). 1. CIRCUIT DESCRIPTIONS

Page 2

CX-3078 3 5 678 567 8 C D F A B E – ++ OFFSET ADJ 1+(Pfbal/0x10000) 1+(Pfbal/0x10000) 1-(Pfbal/0x10000) Analog block Servo block FE+ Pfepofs – ++ OFFSET ADJ FE- Pfenofs 1+(Pfbal/0x10000) 1-(Pfbal/0x10000) 1+(Pfbal/0x10000) 1-(Pfbal/0x10000) + VIN6 15– 92 + VIN7 13– 93 + VIN8 11– 94 + VIN5 16– 91 CN1101 B4 B3 B2 B1 – Dfesv FE x1 or x4 – ++ OFFSET ADJ Analog block Servo block TE+ Pfepofs – ++ OFFSET ADJ TE- Pfenofs + VIN2 15– 96 + VIN3 13– 97 + VIN4 11– 98 + VIN1 16– 95 CN1101 B4 B3 B2 B1 – Dfesv TE x1 or x4 –+ –+ –+ –+ EQ EQ EQ EQ PC PC – ++ OFFSET DAC Analog block Servo block TE+ Pfepofs – ++ OFFSET DAC TE- G G Pfenofs + VIN9 VREFH20 kΩ VHALF 17– CN1101 A – Dfesv TE -6dB 15dB(3dB STEP) -6dB 15dB(3dB STEP) 30kHz 30kHz 0dB/12dB 0dB/12dB + VIN10 VREFH20 kΩ VHALF 10– C 1.1.2 FE Generation Circuit Focus Error (FE) Generation Circuit Each of input signals from B1 to B4 which had been quartered by PU within the analog block is input to IC 1501 passing through the resistance and becomes a signal of FE+= -(B1+ B3) and FE -=-(B2+ B4) after adding a focus offset adjustment value. Then, the signal is AD-converted within the servo block and adds an offset cancel value to become FE, generating a signal of FE= (FE+ ) -(FE -). 1.1.3 TE Generation Circuit Trackings Error (TE) Generation Circuit For DVD, TE is generated, with the application of a phase contrast method, from the phase difference of (B2+ B4) and (B1+ B3). For CD, TE is generated, with the application of a 3-beam method, by sending the signal to the variable amp set for the tracking offset adjustment via outer-attached resistance and then by AD-converting it to make the formula of TE= A -C. DVD (TE from phase difference) CD (3-beam TE)