Sega Mega Drive II (Model 2) VA1 — PAL
Sega Corporation · Model Mega Drive II · Rev VA1 PAL (PC BD MD2 VA1 PAL) · 0 scans
Description
The PAL Mega Drive II (Model 2) mainboard, revision VA1, marked PC BD MD2 VA1 PAL. A Motorola MC68HC000 main CPU and a Z80 in a small QFP work alongside Sega's 315-5660 ASIC, which combines the VDP graphics processor, the I/O controller and a YM3438-based FM sound chip. Compared with VA0, VA1 uses one 64 KB VRAM and one 64 KB work RAM chip instead of two of each, and has audio resistor changes to reduce distortion. Video goes through a Fujitsu MB3514 encoder; the 53.203424 MHz master clock is the PAL frequency.
Components (12)
Add or contribute components
| Ref | Type | Part Number | Package | Description | Links | Rating | |
|---|---|---|---|---|---|---|---|
CART1 |
Cartridge slot | 64-pin cartridge connector | 2 × 32 edge connector |
The 64-pin cartridge slot: the 68000's address and data buses, power, audio in and control lines. | |||
ENC1 |
Video encoder | Fujitsu MB3514 | SOP-24 (FPT-24P-M01) |
RGB encoder: turns the VDP's analog RGB and sync into PAL or NTSC composite, S-Video (Y/C) and buffered RGB for the AV socket. | DS | ||
IC1 |
CPU | MC68HC000FN8 | PLCC-68 |
Motorola 68000 main CPU (low-power HCMOS version, 8 MHz grade) in a 68-pin PLCC — the Mega Drive's main processor. | DS | ||
IC4 |
Co-CPU | Z80 CPU (QFP-44) | QFP-44 |
Z80-compatible 8-bit CPU in a small 44-pin QFP: drives the sound chips and runs Master System games. | |||
IC5 |
Sound RAM | Sanyo LC3664BML | SOP-28 |
8K × 8 static RAM: the Z80's 8 KB of sound RAM. | |||
IC6 |
ASIC | Sega 315-5660 (FC1004) | — |
Sega's FC1004-family custom chip: the VDP graphics processor, I/O controller and FM sound in one package. | |||
IC7 |
Video RAM | OKI MSM54C864 | — |
64K × 8 multiport (dual-port) DRAM: the 64 KB video RAM used by the VDP inside the 315-5660. | |||
OP1 |
Audio op-amp | C324G (LM324-type quad op-amp) | SOP-14 |
LM324-type quad operational amplifier in the audio circuit (two of these mix and amplify the FM, PSG and cartridge sound). | |||
OP2 |
Audio op-amp | C324G (LM324-type quad op-amp) | SOP-14 |
LM324-type quad operational amplifier in the audio circuit (two of these mix and amplify the FM, PSG and cartridge sound). | |||
OSC1 |
Master clock | 53.203424 MHz oscillator | — |
53.203424 MHz master clock oscillator (PAL) — every clock on the board is divided down from it. | |||
REG1 |
Voltage regulator | 7805 | TO-220 |
7805 linear regulator: makes the board's +5 V from the DC adapter's input. | DS | ||
WRAM |
Work RAM | Sanyo LC331632M-12 | — |
32K × 16 pseudo-static RAM (120 ns): the 68000's 64 KB of work RAM. |
sega megadrive model2 va1 pal 68000 retro
Specifications
Form FactorHome console mainboard
Components12
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