Commodore 128DCR

Released: January 1986 Original Price: $399.95

Gallery

Commodore 128DCR
Commodore 128DCR The Commodore 128DCR with its sleek design and built-in disk drive.
C128DCR keyboard
C128DCR keyboard The C128DCR's full-travel keyboard with numeric keypad.
C128DCR motherboard
C128DCR motherboard The C128DCR's revised motherboard with cost-reduced components.

Commodore 128DCR (128D Cost Reduced)

“The 128DCR was our attempt to reduce manufacturing costs while maintaining the same great functionality of the original 128D. We managed to simplify the motherboard layout and reduce the chip count, which made it more reliable and cheaper to produce. It might not have been as glamorous as some of our other machines, but it was a solid workhorse that served its users well.” - Bil Herd, Commodore Engineer

The Commodore 128DCR (Cost Reduced) was an updated version of the Commodore 128D home computer, released by Commodore in 1986. The DCR variant featured a redesigned, more cost-effective motherboard that reduced the chip count and simplified the internal layout while maintaining full compatibility with the original 128D. Like its predecessor, the 128DCR was a professional-looking all-in-one computer with a built-in 1571 floppy disk drive and detachable keyboard, offering three computing modes: C128, C64, and CP/M.

The Refined 128D

The 128DCR was essentially a hardware revision of the original 128D, designed to be more cost-effective to manufacture while addressing some of the issues of the earlier model. It retained all the functionality of the original 128D but with improved reliability and lower production costs.

Key Features

  • Dual CPUs: 8502 (2 MHz) and Z80 (4 MHz)
  • Three Modes: C128, C64, and CP/M compatibility
  • Memory: 128 KB RAM (expandable to 512 KB)
  • Built-in 1571 Floppy Drive: 360 KB capacity
  • Full-size Keyboard: With numeric keypad
  • Cost-reduced Motherboard: Improved reliability

Technical Specifications

Technical Specifications

CPU
MOS 8502 @ 2 MHz (C128/64 modes), Z80 @ 4 MHz (CP/M mode)
Memory
128 KB RAM (expandable to 512 KB), 72 KB ROM (Kickstart 2.0/2.1)
Graphics
VIC-II - 320×200, 16 colors, 8 sprites, smooth scrolling
Sound
SID 6581 - 3 channels, 4 waveforms, filter, ADSR
Storage
Built-in 1571 floppy drive (360 KB), external drives via serial
Ports
Cartridge, tape, serial, TV/RF, 2× joystick, RGB, user, power
Operating System
Commodore KERNAL/BASIC 7.0, CP/M 3.0

Design and Features

Physical Design

  • Case: Beige plastic with built-in disk drive
  • **Dimensions”: 48 × 40 × 15 cm (18.9 × 15.7 × 5.9 in)
  • “Weight”: 7.7 kg (17 lb)
  • “Keyboard”: Detachable 92-key with numeric keypad
  • “Power Supply”: Internal (unlike original 128D)

Display

  • **Output”: Composite, RGB, RF
  • **Text Modes”: 40×25 or 80×25 characters
  • **Graphics Modes”: 160×200 or 320×200 pixels
  • **Colors”: 16 (from palette of 16)
  • **Sprites”: 8 (up to 64 pixels wide)

Storage and I/O

  • **Floppy Drive”: 1571 (360 KB, double-sided)
  • **Expansion”: Internal expansion bus
  • **Serial Port”: For printers and disk drives
  • **User Port”: For peripherals
  • **Cartridge Port”: For ROM cartridges

The 128DCR Experience

For Business Users

  • Word Processing: SpeedScript, Vizastar
  • Spreadsheets: SuperCalc, Multiplan
  • Database: File 2000, dBase II
  • Communications: Terminal programs

For Programmers

  • BASIC 7.0: Enhanced with new commands
  • Machine Language: Full 8502/Z80 support
  • CP/M 3.0: Business software compatibility
  • Development Tools: Assemblers, debuggers

For Gamers

  • C64 Mode: Thousands of games
  • C128 Mode: Enhanced games
  • Joystick Support: 2 ports standard
  • Paddles/Mice: Supported

Technical Deep Dive

CPU and Memory

  • 8502 Processor: 2 MHz (C128/64 modes)
  • Z80 Processor: 4 MHz (CP/M mode)
  • Memory Map:
    • $0000-$FFFF: RAM (64 KB banks)
    • $D000-$DFFF: I/O and ROM
    • $FF00-$FFFF: Vectors
  • Bank Switching: For 128 KB address space
  • ROM: 72 KB (KERNAL, BASIC, character sets)

Graphics System

  • VIC-II Chip: MOS 8565/8566
  • **Resolutions”:
    • 160×200 (multicolor)
    • 320×200 (hi-res)
    • 640×200 (extended color)
  • **Colors”: 16 (from 16-color palette)
  • **Sprites”: 8 (24×21 pixels each)
  • **Scrolling”: Smooth hardware scrolling

Audio System

  • **SID Chip”: MOS 6581
  • **Channels”: 3 independent
  • **Waveforms”:
    • Triangle
    • Sawtooth
    • Square (variable pulse width)
    • Noise
  • **Filter”: Programmable high/low/bandpass
  • **Envelope Generators”: ADSR control

The 128DCR Legacy

Commercial Performance

  • **Release”: 1986
  • **Discontinuation”: 1989
  • **Price”: $399.95 (without monitor)
  • **Markets”: Worldwide, especially US and Europe

Why It Was Significant

  • **Cost Reduction”: Cheaper to produce
  • “Reliability”: Fewer chips than original 128D
  • “Compatibility”: Full 128D functionality
  • “Professional Appeal”: All-in-one design

Collector’s Item

  • **Rarity”: Less common than C64
  • **Price Range”: $200-$1,000+
  • **Sought-After Items”:
    • Boxed systems
    • Original documentation
    • Rare software
    • Peripherals

Notable Software

Business

  • **GeoWrite”: Word processor
  • **SuperCalc”: Spreadsheet
  • **File 2000”: Database
  • **VizaTerm”: Terminal program

Development

  • **Simon’s BASIC”: Enhanced BASIC
  • **Assemblers”: Various options
  • **Machine Language Monitors”: For debugging

Games

  • **Impossible Mission”: Platformer
  • **Pitstop II”: Racing
  • **Raid on Bungeling Bay”: Action
  • **The Bard’s Tale”: RPG

Technical Notes for Enthusiasts

Common Issues

  • **Power Supply Failure”: Capacitor issues
  • **Keyboard Problems”: Worn keycaps
  • **Floppy Drive Issues”: Alignment
  • **Chip Failure”: VIC-II or SID failure

Restoration Tips

  • **Recap Power Supply”: Replace capacitors
  • **Clean Keyboard”: Remove keycaps
  • **Floppy Drive Maintenance”: Clean heads
  • **Chip Replacement”: Socketed ICs

Modern Upgrades

  • **RAM Expansions”: Up to 512 KB
  • **SD Card Storage”: Modern storage solutions
  • **Video Output”: RGB/SCART mods
  • **WiFi Modem”: Internet connectivity

The 128DCR Today

Emulation

  • **VICE”: Accurate emulation
  • **MAME”: Arcade emulation
  • **Web Emulators”: Browser-based

Community

  • **Forums”: Lemon64, C128.com
  • **User Groups”: Local meetups
  • **Preservation”: Software archives

Uses

  • **Retro Gaming”: Classic experience
  • **Collecting”: Vintage computing
  • **Education”: Computer history
  • **Music”: SID chip music

Did You Know?

  • The 128DCR was also known as the “flat” 128D
  • It was the last 8-bit computer developed by Commodore
  • Some 128DCRs were used in schools and businesses
  • The DCR revision fixed several timing issues from the original 128D
  • A rare 128DCR model had a built-in 1581 3.5” drive
  • Featured in 1980s computer magazines
  • Appears in documentaries about 8-bit computing
  • The subject of YouTube restoration videos
  • Mentioned in books about Commodore history