C128DCR Assembly 250477
Released in 1986.
Schematic Number 252451.
Mainboard used in the low cost version of the C128D (C128DCR).
Plastic case instead of a metal case like the C128D.
Improved 80 column mode video chip.
Specs
CPU : 8502 @ 1–2
MHz / Zilog Z80A, or Zilog Z80B @ 4
MHz
RAM : 128kB DRAM
ROM (C64 Mode) : 16kB ROM Total - 8k BASIC, 8k Kernal
ROM (C128 Mode) : 64kB ROM Total - 48k BASIC, 16k Kernal, 16k C128 BIOS
ROM (CP/M) : 4kB CPM/BIOS
Graphics : VIC-II (40 col mode) / VDC-8563 (80 col mode)
Sound : SID
Interfaces : 2 Control Ports, A/V, RGBI, Datasette Port, Expansion Port, Serial IEC, TV RF, User Port
Keyboard : 92 Keys (External)
Power Supply : External Transformer (9V AC + 5V DC)
Schematics
Fig. 1: C128DCR 250477 Mainboard
Capacitor List
Cap - Value - Rating - Type
C35 - 4.7uf - 50v - Radial
C61 - 10uf - 16v - Radial
C63 - 100uf - 6.3v - Radial
C69 - 10uf - 25v - Radial
C85 - 10uf - 25v - Radial
C88 - 1000uf - 25v - Axial
C91 - 1uf - 50v - Radial
C92 - 10uf - 25v - Radial
C100 - 220uf - 16v - Axial
C109 - 10uf - 25v - Radial
C115 - 10uf - 25v - Radial
C140 - 1uf - 50v - Radial - Non-Polar
C141 - 1uf - 50v - Radial - Non-Polar
IC List
PCB ID | Chip ID | Notes |
U1 | 6526 | CIA 1 |
U2 | 4066 | Quad Bi-Switch |
U3 | 74LS138 | Demultiplexor |
U4 | 6526 | CIA 2 |
U5 | 8580 | SID |
U6 | 8502 | Processor |
U7 | 8722 | MMU |
U9 | 74F32 | Quad 2-Input Gate |
U10 | Z80B | Processor |
U11 | 8721 | PLA |
U17 | 74ALS373 | Octal Latch |
U18 | 2364 | ROM - Char |
U19 | 2016 | SRAM |
U20 | 4066 | Quad Bi-Switch |
U21 | 8564/8566 | VIC-II |
U22 | 8568 | CRT Control |
U23 | 4464 | DRAM - CRT |
U25 | 4464 | DRAM - CRT |
PCB ID | Chip ID | Notes |
U27 | 556 | Dual Timer |
U28 | 8701C | Clock Generator |
U32 | 27256 | ROM - Basic |
U34 | 27256 | ROM - ROM - Kernal & Basic |
U36 | 23256 | ROM - Function |
U38 | 41254 | DRAM |
U39 | 41254 | DRAM |
U40 | 41254 | DRAM |
U41 | 41254 | DRAM |
U55 | 74F245 | Octal Bus Transceiver |
U102 | 27256 | ROM Drive |
U103 | 2016 | SRAM |
U104 | 6522A | VIA 1 |
U106 | 6522A | VIA 2 |
U107 | 5710 | FDC |
U108 | CX20185/MC28719/LA8200 | FDD R/W AMP |
U109 | UPA2003C | NEC |
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