Coleco Adam
 | |
| Adam memory console and keyboard at the Computer History Museum (Andrew Lih, CC BY-SA 2.0) | |
| Specifications | |
|---|---|
| Manufacturer | Coleco Industries |
| Type | Home computer |
| Released | October 1983[1] |
| Discontinued | January 1985[1] |
| Intro price | US$725 (at launch)[1] |
| CPU | Zilog Z80A, 3.58 MHz clock[2] |
| Memory | 64 KB RAM; 16 KB video RAM[2] |
| Storage | Digital data pack drive, up to 256 KB per pack; space for a second drive[2] |
| Display | RF output to a TV, or composite video and audio to a monitor[3] |
| Sound | Texas Instruments SN76489 sound generator[2] |
| Graphics | Texas Instruments TMS9928 video display processor[2] |
| Input | 75-key keyboard; ColecoVision game controllers[2] |
| Ports / interface | AdamNet, expansion port, three internal card connectors, ColecoVision cartridge slot[2] |
| Power | Supply in the SmartWRITER printer: +5 V, −5 V, +12 V inductive, +12 V logic and 18 V unregulated[2] |
| OS / Firmware | SmartWRITER and EOS in ROM, OS 7; SmartBASIC on data pack[2] |
The Coleco Adam is Coleco's home computer of 1983, built on the hardware of the ColecoVision games console.[1] It came in two forms: a complete system, and Expansion Module #3, which turned an existing ColecoVision into an Adam. Either way it has a Z80A processor, 64 KB of RAM, a TMS9928 video chip, high-speed digital data pack tape drives, a keyboard and a daisy-wheel printer, the SmartWRITER, which also contains the power supply for the whole system.[2] Every part of the system is linked by AdamNet, a serial bus run by Motorola 6801 microcontrollers in the memory console and in each peripheral.[2][4]
Models
[edit | edit source]Coleco sold the Adam in two models, the complete system and Expansion Module #3. When the Expansion Module #3 memory console is connected to a ColecoVision, the two are essentially identical in function.[2]
Complete system
[edit | edit source]The complete ("standalone") Adam has its own ColecoVision cartridge slot in the memory console, so it plays ColecoVision cartridges without a console. It has two reset switches: COMPUTER RESET restarts the Adam side, and CARTRIDGE RESET starts a ColecoVision cartridge.[3][4]
Expansion Module #3
[edit | edit source]Expansion Module #3 plugs into a ColecoVision, which takes the place of the complete system's CPU board: the Technical Reference Manual describes the reset and system clock lines of the Memory and I/O board as connecting to "the ColecoVision or CPU Board".[2] Coleco's check-out guide says that with Expansion Module #3 attached, the ColecoVision's own power supply must not be plugged in and its ON/OFF switch must stay off; the printer powers everything.[3]
History
[edit | edit source]Coleco announced the Adam at the Summer Consumer Electronics Show in June 1983, promising shipments in August, but missed a series of shipping dates through October; the printer was the main cause of the delays. Between announcement and shipment the price rose from US$525 to US$725. Coleco shipped only 95,000 units by December 1983, against a goal of half a million, and many were returned as defective. It announced on 2 January 1985 that it was discontinuing the Adam.[1]
Hardware
[edit | edit source]| Unit | Main parts |
|---|---|
| Memory console, Memory and I/O board | Master 6801 microcomputer (2 KB ROM, 128 bytes RAM, UART, 1 MHz from a 4 MHz crystal); MIOC custom chip linking the 6801 to the Z80; eight 64K dynamic RAMs; EOS ROM; a second 6801 for the tape drives; three card connectors and the expansion port |
| Memory console, CPU board | Z80A; 8 KB OS 7 ROM and the cartridge connector (up to 32 KB); TMS9928 video display processor with 16 KB video RAM in eight 16384 × 1 chips; SN76489 sound generator; RF modulator; game controller circuits |
| Digital data drives | Reel-to-reel tape in a Lexan cassette, up to 256 KB per data pack; read/write and servo boards |
| Keyboard | 75 full-travel keys with six "smart keys"; a 6801 on the keyboard board |
| SmartWRITER printer | Daisy-wheel printer, 10 characters per inch, 10 characters per second, paper up to 9½ in wide; a 6801 printer board and the linear power supply board |
All from Coleco's ADAM Technical Reference Manual.[2]
AdamNet is a 62.5 kbit/s half-duplex shared serial bus. The Z80 is the master processor of the system; the Master 6801 in the memory console runs the network for it and talks to the 6801s in the keyboard, the printer and the tape drives.[2] Leaded Solder notes that the keyboard's controller, marked SC85262P, is a 6801 with its program in mask ROM.[4]
Power supply
[edit | edit source]The whole system runs from the linear power supply in the SmartWRITER printer. It turns the mains into four regulated rails and an unregulated 18 V for the printer's ribbon solenoid.[2]
| Rail | Use | To memory console | To printer | Protection |
|---|---|---|---|---|
| +5 V | Main supply to the CPU | 2.75 A | 0.25 A | Fuse and foldback current limiting |
| −5 V | CPU | 0.2 A | – | Current limiting and thermal shutdown |
| +12 V inductive (+12VI) | Motors, solenoids and the data drives | 0.6 A | 1.95 A | Fuse and foldback current limiting |
| +12 V logic (+12VL) | System logic | 0.3 A | – | Foldback current limiting, no fuse |
| +18 V unregulated | Printer ribbon solenoid | – | 1.0 A | Shares the +12VI fuse |
A thermal fuse in the transformer protects against overload, and the mains input may range from 108 V to 132 V AC.[2] The supply was designed for 120 V 60 Hz mains.[5] The power goes to the memory console through a cable of seven insulated wires and a drain wire; its pinout and the regulator circuit are on Coleco Adam Troubleshooting Guide.
Video and audio
[edit | edit source]The memory console's RF output feeds a TV on channel 3 or 4, chosen with a switch on the back. For a monitor, the console has a composite video output and a 7-pin DIN socket marked AUX VIDEO, which carries audio on pin 1, composite video on pin 3 and ground on pin 4.[3]
Repair
[edit | edit source]- Coleco Adam General Maintenance: data packs and drives, the printer mechanism, cleaning and the power supply.
- Coleco Adam Troubleshooting Guide: Coleco's check-out procedure, power faults and rail checks.
- Coleco Adam Capacitor Replacement Guide: the electrolytic capacitors of the power supply, printer and data drives, from Coleco's schematics.
Documentation
[edit | edit source]Coleco Adam Documentation describes the hosted Coleco documents: the Technical Reference Manual, the schematic set, the System Check-Out and Trouble-Shooting Guide and the Set-Up Manual.
Gallery
[edit | edit source]-
Complete Adam with the SmartWRITER printer on the right -
Memory console, keyboard, controller and data packs -
Underside of the memory console
Related pages
[edit | edit source]- Coleco Adam General Maintenance
- Coleco Adam Troubleshooting Guide
- Coleco Adam Capacitor Replacement Guide
- Coleco Adam Documentation
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 Wikipedia, "Coleco Adam" (retrieved 2026-10-06), for history only: announcement at the 1983 Summer CES, missed shipping dates, the printer as the main cause of delay, the price rise from $525 to $725, 95,000 units shipped by December 1983, defect complaints, discontinuation announced 2 January 1985.
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 2.14 2.15 2.16 Coleco Industries, ADAM Technical Reference Manual, Preliminary Release: chapter 1 (hardware overview, models, data packs, keyboard, printer; PDF pp. 8–12), chapter 2 section 2.1 (Memory and I/O board, Master 6801, dynamic RAM; pp. 16–18; interconnects to the ColecoVision or CPU board, p. 25), section 2.2 (CPU board, Z80A, OS 7 ROM, TMS9928 VDP and video RAM, SN76489; pp. 32–34), section 3 (keyboard; p. 43), section 4 (printer; p. 45), section 6 (power supply, protection, interface cable and output currents; pp. 48–49), appendix 4.4 (linear power supply schematic and parts list; pp. 150–152). Hosted here as File:Coleco Adam Technical Reference Manual (Preliminary Release).pdf (see Coleco Adam Documentation).
- ↑ 3.0 3.1 3.2 3.3 Coleco Industries, ADAM System Check-Out and Trouble-Shooting Guide, code 42464E, 1983: operating tips (108–132 V line voltage, data packs), set-up diagrams for the complete system and Expansion Module #3, the power-on checks, the reset switches, the keyboard, game controller, data drive and data pack checks, drive removal, printer checks and adjustments, monitor connection and the AV DIN pinout. Hosted here as File:Coleco Adam System Check-Out and Trouble-Shooting Guide 42464E.pdf (see Coleco Adam Documentation).
- ↑ 4.0 4.1 4.2 "I don't know you from Adam", Leaded Solder, 19 November 2022, leadedsolder.com (retrieved 2026-10-06). Restoration of an Adam memory console and keyboard: the two reset switches; AdamNet and its 6801 microcontrollers; the keyboard's construction (membrane, rubber domes, Motorola 6801-family controller, LM339); the power supply being in the printer; an external replacement supply built from a Mean Well RQ-50B with the DE-9 connector pinout.
- ↑ Coleco Industries, Schematic, Linear Power Supply, drawing 41234 revision E, used on 83-101; sheet 7 of File:Coleco Adam Schematics.pdf (see Coleco Adam Documentation): 120 V AC 60 Hz input; transformer windings of 7.25, 14.0, 15.0 and 8.25 V AC; µA723 regulators U1–U3 with 2N3055, TIP31A and TIP41A pass and driver transistors; 79M05 for −5 V; 5 A slow-blow fuses F1 and F3; capacitor values.