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Sega CD 2 / Mega CD 2 - Service Manual

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The Sega Service Manual, SEGA CD II / MEGA CD II is Sega Enterprises, Ltd.'s service manual No. 002, issued August 1993, for the Sega CD II and Mega CD II. It runs to 42 printed pages; the scan has 43 PDF pages and a text layer. Units with serial number T30282001 and later have a revised board, covered by the June 1994 supplement No. 002-2.

Contents

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Service manual No. 002 contents
Section Page
1. Specifications 2
2. Identifying parts 3
3. Disassembly 4
4. CD drive adjustment 6
5. CD interface 8
6. CD drive unit replacement procedure 9
7. TOC read-in flowchart 10
8. Guides for servicing: focus, tracking, disc and feed circuit flowcharts 11
9. Block diagram 15
10. Schematic diagrams 16
11. Circuit board diagrams 18
12. Parts specifications 18
13. Exploded view and parts list: 13-1 exploded view (38), 13-2 mechanical parts list (39), 13-3 electrical parts list (39), 13-4 accessories and package list (42) 38

What this manual settles

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  • Specifications (p. 2): Sega CD II AC 120 V 60 Hz, Mega CD II AC 230 or 240 V 50 Hz, both 18 W; 396 × 220 × 84 mm; 68000 at 12.5 MHz; 6 Mbit program, picture and sound RAM, 512 kbit PCM waveform RAM, 128 kbit CD-ROM cache and 64 kbit back-up RAM; 1 Mbit boot ROM; eight-channel PCM at up to 32 kHz; average access time 1.5 s; battery back-up of about one month.
  • The CD drive adjustment (pp. 6-7) needs Sega's adjustment jig, a frequency counter, an oscilloscope, an audio generator, two voltmeters and a Sony TYPE-4 test disc. It has three steps: VCO, setting VR403 for 4.320 ± 0.05 MHz at TP-PLCK; EF balance, setting VR401 in test mode 2 so the two peaks of the tracking error signal at TP-X are equal; and tracking gain, setting VR402 in test mode 3 with a 1.0 kHz, 0.15 Vrms signal injected until the two voltmeters read the same.
  • The boards are the main board 837-9615 (Sega CD II, USA) or 837-9616 (Mega CD II, multi), with the PCM sub-board 837-9798.
  • Capacitors are numbered in one C series in blocks of hundreds by circuit area (C1xx, C2xx, C3xx, C4xx, C9xx), with no separate CE series. Electrolytics are identified by Sega's 150-xxxx part numbers, for example 150-0439 10 µF 16 V, 150-0440 100 µF 6.3 V, 150-0441 1000 µF 6.3 V and 150-0249 330 µF 16 V.

What this manual does not contain

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  • The revised board fitted from serial number T30282001, which uses larger chip resistors and capacitors, a different board pattern and renumbered ICs. Use the supplement for those units.
  • Anything on the Model 1 or the host console.

Pages that cite this document

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Download: sega cd 2 - mega cd 2 - service manual.pdf

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