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Amstrad NC100 Maintenance Guide

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An Amstrad NC100 Notepad

The Amstrad NC100 keeps everything the owner types in battery-backed RAM, so its maintenance is mostly about power: the four AA cells, the CR2032 lithium backup cell, the mains adaptor and any memory card. Amstrad's user manual gives the battery and adaptor rules; Hans-Jürgen Böhling's surgical guide gives the inside of the machine.[1][2] Faults are in the Amstrad NC100 Troubleshooting Guide.

Back up first

Any work that removes all power erases the documents, addresses and diary entries held in memory.[1] Before opening the case or changing the lithium cell, copy the files to a memory card or transfer them over the serial port. Nixon's Advanced User Guide recommends transferring anything worth keeping to another computer before experimenting, because a crash can lose all the data in the machine.[3]

Main batteries

The NC100 takes four AA cells. Amstrad recommends alkaline LR6 cells, which it rated at about 35 to 40 hours of use, and allows NiCd rechargeables, which give about 5 hours.[1] When they run low the screen shows a message asking for the batteries to be replaced.[1]

  • Change the AA cells with the lithium cell in place, or with the mains adaptor connected, so the memory stays powered.[1]
  • Take flat cells out promptly. Alkaline cells that leak in the compartment corrode the contacts; see Battery Explosion, Capacitor or Corrosion Damage for cleaning.
  • Clean dull or corroded battery contacts and check the springs before blaming the electronics.

The automatic power-off delay is five minutes by default. Amstrad warns against setting it to 0 (never) on batteries, because the machine will then stay on and drain them.[1] Serial transfers drain the batteries faster than normal use, and Amstrad suggests the mains adaptor for file transfers.[1]

Lithium backup cell

The backup cell is a CR2032, which Amstrad says keeps the memory when no other power is present and estimated to last about five years. When it runs low the screen shows "Lithium battery is low". To replace it:[1]

  1. Make sure good alkaline cells are fitted or the mains adaptor is connected.
  2. Open the lithium battery cover on the underside. Böhling's drawing of the underside marks a screw beside it.[2]
  3. Fit a new CR2032 of the same type, the correct way round.
  4. Do not try to recharge the old cell or put it in a fire.

A new machine is shipped with a white plastic film that has to be pulled completely out from the underside before first use.[1] If a second-hand NC100 loses its memory at every battery change, check the lithium cell first.

Mains adaptor

Amstrad's instructions are to use only the adaptor supplied with the Notepad, to keep the Notepad close to the socket so the lead is not strained, and to unplug the adaptor from the wall and the Notepad when finished.[1] Böhling's power supply diagram marks the adaptor input as 6 V DC and shows a fuse, F301, in the input line inside the machine.[2] Check the polarity and voltage of any replacement adaptor against the original before connecting it.

Memory cards

The slot takes PCMCIA/JEIDA Type I SRAM cards of up to 1 MB at 5 V. Flash cards are not suitable.[2] A card must be formatted from the stored-documents menu before use, and the card's own battery and write protection follow the card maker's instructions.[1] A card keeps its contents through a reset of the Notepad, which makes it the simplest backup.[1]

Opening the case

Böhling's procedure:[2]

  1. Save all your data.
  2. Lay the Notepad face down and remove the four AA cells.
  3. Remove the five screws, including the one under the battery cover. One of the screws holds the firmware EPROM cover.
  4. Turn the Notepad the right way up and lift off the upper part of the case slowly. The display and the speaker stay connected to the main board by a flat cable and a lead.
  5. Pull the display cable and speaker lead out of their sockets to separate the halves.

Removing the AA cells leaves the lithium cell powering the memory. Keep the board clear of metal tools while it is exposed. The board is surface-mount apart from the firmware EPROM, which is on the underside behind its own cover.[2]

Display and keyboard

The brightness control is on the right-hand edge of the case. If the screen is blank or faint at switch-on, adjust it before suspecting a fault.[1] The display connects to the board through the flat cable described above; reseat it if the case has been opened.[2]

References

  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 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 (white film, batteries, brightness control); mains adaptor p. 4; powering the Notepad and lithium battery p. 43; automatic power off p. 44; memory cards p. 47; resetting p. 60; serial transfers p. 109.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 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. Batteries and backup cell; opening the case; board and IC table; power supply block diagram; PCMCIA slot.
  3. ↑ Robin Nixon and Chris Nixon, The Amstrad Notepad Advanced User Guide (Sigma Press, 1993), pp. 187–188 (reset and lock-up recovery). Scan at archive.org. Retrieved 2026-10-02.


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