Editing Amstrad NC100

{{Infobox computer
| name         = Amstrad NC100 Notepad
| image        = [[File:Amstrad NC100.jpg|260px|frameless]]
| caption      = NC100 with a UK keyboard
| manufacturer = Amstrad plc
| type         = Notebook computer
| release date = July 1992
| price        = £199
| cpu          = Zilog Z84C00 (Z80-compatible CMOS), 4.606&nbsp;MHz
| memory       = 64 KB SRAM (two µPD43257A)
| rom          = 256 KB firmware EPROM (µPD27C2001)
| storage      = PCMCIA/JEIDA Type I SRAM card, up to 1 MB
| display      = 480 × 64 pixel LCD, 80 × 8 characters, not backlit
| ports        = Centronics parallel (DB-25), RS-232 serial (DE-9)
| power        = Four AA cells or mains adaptor; CR2032 lithium backup cell
| dimensions   = 295 × 210 × 22&nbsp;mm
| weight       = 930&nbsp;g
| os           = Built-in Protext-based word processor, diary, address book, calculator, terminal and BBC BASIC
| successor    = [[Amstrad NC150]]
}}
<templatestyles src="Template:StyledTable/styles.css" />
The '''Amstrad NC100 Notepad''' is an A4-sized, Z80-based portable computer that Amstrad released in 1992. It has a full-size keyboard, an eight-line by 80-column LCD, and its software in ROM: a word processor, address book, diary, calculator, a terminal program and BBC BASIC. It runs from four AA cells or a mains adaptor, with a lithium coin cell keeping the memory alive while the cells are changed.<ref name="wpnc">Wikipedia, [https://en.wikipedia.org/wiki/Amstrad_NC100 "Amstrad NC100"], lead and section "Upgrades". Retrieved 2026-10-02. Release in July 1992, the built-in software, the 80 × 8 unlit screen, the serial, parallel and PC card ports, and the NC150 and NC200.</ref><ref name="uinc">Amstrad plc, ''Amstrad Notepad Computer'' user manual. Hosted as [[:File:Amstrad Notepad Computer User Manual.pdf]], described at [[Amstrad Notepad Computer User Manual]]. Setting up pp. 1–2; mains adaptor p. 4; powering the Notepad p. 43; automatic power off p. 44; memory cards p. 47; resetting p. 60.</ref> The Centre for Computing History gives its price as £199 and dates its own unit to August 1992.<ref name="cch">Centre for Computing History, [http://www.computinghistory.org.uk/det/49463/Amstrad-NC100/ "Amstrad NC100"], exhibit CH49463. Retrieved 2026-10-02. The £199 price and an August 1992 unit.</ref>

== History ==

Wikipedia gives the release as July 1992, when ''Newsbytes'' reported the unveiling; Tim Surtell's NC users' site gives September 1992 for the launch.<ref name="ncusintro">Tim Surtell, Tim's Amstrad NC Users' Site, [http://www.ncus.org.uk/intro.htm "Introduction"] and [http://www.ncus.org.uk/specs.htm "Specifications of the NC Computers"]. Retrieved 2026-10-02. Launch dates of the NC100 (September 1992), NC150 (April 1993) and NC200 (October 1993); the NC150's 128 KB RAM, French and Italian versions and optional external floppy drive; 4 × AA cells and a 6 V mains adaptor for the NC100 and NC150.</ref> Two related models followed: the [[Amstrad NC150]], sold only in Italy and France in the same case from April 1993, and the NC200, a clamshell model with a backlit 80 × 16 screen and a 3.5-inch disc drive.<ref name="wpnc" /> Both the NC100 and NC200 were also sold in North America as the Dreamwriter 325 and Dreamwriter 200.<ref name="wpnc" />

== Hardware ==

Hans-Jürgen Böhling's teardown, ''A Surgical Guide To The Amstrad Notepad Computer'', describes the board. His German NC100 board is marked Amstrad plc 4500-001P-1. Every IC is surface-mounted except the firmware EPROM, IC303, which sits under its own cover on the underside.<ref name="sg">Hans-Jürgen Böhling, ''A Surgical Guide To The Amstrad Notepad Computer''. Community document, hosted as [[:File:Amstrad NC100 Surgical Guide.pdf]], described at [[Amstrad NC100 Surgical Guide]]. Specification, opening the case, board and IC table, block and power supply diagrams, EPROM and RAM link tables, PCMCIA slot.</ref>

{| class="wikitable styled-table" style="width:70%; text-align:left;"
|+'''NC100 main ICs (Böhling's surgical guide)'''
! IC !! Part !! Function
|-
| IC301 || Zilog Z84C0006FEC || Z80-compatible CPU, 6&nbsp;MHz part
|-
| IC302 || NEC µPD65034 || Custom ASIC: clocks, keyboard, printer and LCD interface, memory management, PCMCIA, sound
|-
| IC303 || NEC µPD27C2001 || 256K × 8 firmware EPROM
|-
| IC304, IC305 || NEC µPD43257A || 32K × 8 SRAM, on the lithium-backed supply
|-
| IC307 || Toshiba TC8521 || Real-time clock, on the lithium-backed supply
|-
| IC308 || NEC µPD71051 || UART
|-
| IC309 || NEC µPD4711 || RS-232 line driver
|-
| IC312 || LM339 || Comparators for battery level detection
|}

Böhling also tabulates zero-ohm links beside IC303 that select larger ROM types (27C4001, 23C2001, 23C4001 or 23C8001) and links that allow 43256 RAMs with the unfitted IC310.<ref name="sg" /> The memory card slot takes 5&nbsp;V PCMCIA/JEIDA Type I SRAM cards of up to 1&nbsp;MB; flash cards do not work.<ref name="sg" /> Amstrad's manual says cards must be formatted from the stored-documents menu before use.<ref name="uinc" />

Böhling gives the clock as 4.606&nbsp;MHz; Wikipedia gives 4&nbsp;MHz.<ref name="sg" /><ref name="wpnc" />

== Power ==

{| class="wikitable styled-table" style="width:100%; text-align:left;"
|+'''NC100 power sources'''
! Source !! Details
|-
| Four AA cells || Alkaline LR6, about 35 to 40 hours; NiCd rechargeables about 5 hours (Amstrad)
|-
| Mains adaptor || The supplied adaptor only; Böhling's power diagram marks the input as 6&nbsp;V DC, with fuse F301
|-
| CR2032 lithium cell || Keeps the memory and clock when no other power is present; Amstrad estimated its life at five years
|}

Amstrad's figures are from the user manual; Wikipedia gives up to 20 hours on four AA cells.<ref name="uinc" /><ref name="wpnc" /> Böhling's power supply diagram shows a DC/DC converter producing +6&nbsp;V, +5&nbsp;V, a lithium-backed 5&nbsp;V line for the RAM and clock, and −15&nbsp;V for the LCD, with a battery-level detector that signals the custom chip.<ref name="sg" /> The supplied adaptor gives 300&nbsp;mA at 6&nbsp;V DC and is not regulated.<ref name="ncushw">Tim Surtell, Tim's Amstrad NC Users' Site, [http://www.ncus.org.uk/qanda_hardware.htm "Questions & Answers: Hardware"]. Retrieved 2026-10-02. Community answers: the blank-screen checklist from the NC200 manual, the internal surface-mount fuse (6 V 0.8 A on the NC100), adaptor rating and polarity, mains lead repair, case cracking, the NC100 display ribbon cable, serial port reliability, memory cards up to 1 MB, and Cliff Lawson on the NC150's Ranger disk hook.</ref> The [[Amstrad NC100 Troubleshooting Guide]] gives the warning thresholds. If every power source is removed at once, the documents, addresses and diary entries in memory are lost.<ref name="uinc" />

== Repair guides ==

* [[Amstrad NC100 Maintenance Guide]] – batteries, the lithium cell, memory cards, opening the case
* [[Amstrad NC100 Troubleshooting Guide]] – power, low-battery warnings, lock-ups and resets, display and port faults

== Documentation ==

* [[Amstrad Notepad Computer User Manual]] – Amstrad's user manual
* [[Amstrad NC100 Surgical Guide]] – Böhling's teardown and IC reference
* Robin Nixon and Chris Nixon, ''The Amstrad Notepad Advanced User Guide'' (Sigma Press, 1993), on [https://archive.org/details/amstrad-notepad-advanced-user-guide archive.org]

== Gallery ==

<gallery mode="packed" heights="180">
File:Amstrad NC100 (German, main menu).jpg|A German NC100 at its main menu
File:Amstrad NC100 Notepad.jpg|NC100 with a UK keyboard
</gallery>

== Related pages ==

* [[Amstrad NC150]]
* [[Battery Refurbishment]] · [[Battery Explosion, Capacitor or Corrosion Damage]]

== References ==
<references />

{{Navbox-Amstrad|state=collapsed}}

[[Category:Amstrad]]