Amstrad NC100 Notebook Computer Fuse Replacement

I recently acquired a faulty Amstrad NC100 "Notebook Computer" from around 1992.

These were designed to be a simple to use computer for people who didn't know how to use computers. It has a built-in word processor, organiser, calculator and BASIC programming language. They run off AA batteries or a 6 volt DC power supply, and use a CR2032 lithium battery to store the contents of memory as there is no other form of storage.

Mine came complete with the original power supply, carry case and user's manual but wouldn't power on.

I did a little research and the common cause is simply a blown fuse. These use a less-common negative-tip power supply and will blow the fuse if the wrong power supply is connected.

Unfortunately the fuse is a surface mount device soldered to the underside of the main circuit board.

Although the circuit board label for the fuse is 0.8A (F301is the location), mine was fitted with one labelled "20" – which means 2.0A – and looked to be the original. My guess is that blown fuses were a common issue for Amstrad and they may have increased the value during production in hopes of reducing returns.

Sure enough, mine did have a blown fuse and I replaced it with a piece of wire to temporarily test it which is perfectly safe as long as you use a good power supply of the right type.

If you need to obtain a replacement fuse the size is 1210 and they are of a non-resetting type. I found this one on eBay and it appears to be a perfect match.

There are plenty of good instructions on how to disassemble this model, including YouTube videos, so this post is just to recommend which replacement fuse to use.