Text preview for : Pioneer - DEH-24F - 240F- 2400F.rar part of Pioneer - DEH-24F - 240F- 2400F Pioneer Car Audio Pioneer - DEH-24F - 240F- 2400F.rar
Back to : Pioneer - DEH-24F - 240F- | Home
Service
Manual ORDER NO.
CRT2624
CD MECHANISM MODULE
CX-977
- This service manual describes the operation of the CD mechanism module incorporated in models
listed in the table below.
- When performing repairs use this manual together with the specific manual for model under repair.
Model Service Manual CD Mechanism Module
DEH-P630/X1N/UC CRT2648 CXK5500
DEH-P7300R/X1N/EW CRT2649
DEH-P730/X1N/UC CRT2650
DEH-P7350/X1N/ES CRT2651
CONTENTS
1. CIRCUIT DESCRIPTIONS ...........................................2
2. MECHANISM DESCRIPTIONS.................................26
3. DISASSEMBLY .........................................................28
PIONEER CORPORATION 4-1, Meguro 1-Chome, Meguro-ku, Tokyo 153-8654, Japan
PIONEER ELECTRONICS SERVICE INC. P.O.Box 1760, Long Beach, CA 90801-1760 U.S.A.
PIONEER EUROPE NV Haven 1087 Keetberglaan 1, 9120 Melsele, Belgium
PIONEER ELECTRONICS ASIACENTRE PTE.LTD. 253 Alexandra Road, #04-01, Singapore 159936
C PIONEER CORPORATION 2001 K-ZZA. MAR. 2001 Printed in Japan
CX-977
1. CIRCUIT DESCRIPTIONS
From divisional viewpoint, the CX-977 is roughly divided into four sections, namely, Preamplifier, Servo, Power Supply
and Loading Control.
This LSI realizes eight types of automatic adjustments (controls) through cooperative work between Preamplifier and
Servo unit.
Because the system uses the single power source (+ 5v) specification, reference voltages used in the servo system
(Preamplifier, Servo DSP and Pickup) are all Vref (2.1V).
1.1 PREAMPLIFIER (TA2153FN; IC101)
The Preamplifier processes output signals sent from the Pickup and generates signals to supply to each unit of the
next stage, that is, Servo, Demodulator or Control. It also performs power control of Pickup's laser diode. Signals from
the Pickup are I-V-converted by the Preamplifier, which is built-in in Pickup's photo detector, and then added-up by the
RF amplifier to obtain signals such as RF, FE and TE.
Reference voltage, Vref (2.1v), is output from #19 pin of the IC, and 2Vref (4.2v) is supplied to the Servo DSP as the
reference voltage to determine its D range of A/D input.
Fig. 1: TA2153FN circuit
2
CX-977
1) Focus Error Amplifier unit
In this sub-unit, outputs from the photo detector, namely, (A+C) and (B+D), are processed in the differential amplifier
and further in the error amplifier, and then, (A+C-B-D) is output as FE signal from #16 pin of IC101 (TA2153FN).
Low frequency component of voltage FE is expressed as:
FE = (A+C-B-D) x (150k/(51k+1k)) x (60k/60k) x (120k/60k) = 5.77 times
In FE output, "S" curve of approximately 1.45 Vpp on the basis of Vref is obtained. The cutoff frequency of the
succeeding amplifier is 11.4 kHz.
Fig. 2: FE circuit
2) Tracking Error Amplifier unit
In this sub-unit, outputs from the photo detector, namely, E and F, are processed in the differential amplifier and
further in the error amplifier, and then, (E-F) is output as TE signal from #14 pin of IC101 (TA2153FN).
Low frequency component of voltage TE is expressed as:
TE = (E-F) x 300k/100k x 82k/20k = 5.8 times
In TE output, "TE" waveform of approximately 1.51 Vpp on the basis of Vref is obtained. The cutoff frequency of the
succeeding amplifier is 20 kHz.
Fig. 3: TE circuit
3
CX-977
3) RF Amplifier unit
Outputs from the photo detector, namely, (A+C) and (B+D), are added up, amplified and equalized in the Head
Amplifier LSI (TA2153FN). The processed-signals are output to RFI terminal as RF signals (These signals are used to
check eye patterns).
Low frequency component of voltage RFI is expressed as:
RFI = (A+B+C+D) x 5.43
RFI is used for RF Offset Control circuit. These RFI signals so output from #28 pin are AC-coupled outside the unit, and
then re-input to #27 pin and amplified by the RFAGC amplifier to obtain RFO signals.
TA2153FN has built-in function for RFAGC adjustment, as described later, and through such function, the gain of
RFAGC is controlled so that RFO output stays within 1.2