SC143, v1.0, Assembly Guide

Click here for a list of the parts required to build an SC143, v1.0, ROM module.

Experienced builders can just go ahead and populate the board. There shouldn’t be any surprises to catch you out.


This guide assumes you are familiar with assembling circuit boards, soldering, and cleaning. If not, it is recommended you read some of the guides on the internet before continuing.

First check you have all the required components, as listed in the parts list.

Before assembling it is worth visually inspecting the circuit board for anything that looks out of place, such as mechanical damage or apparent manufacturing defects.

If you have a multimeter that measures resistance or has a continuity test function, check there is not a short on the power supply tracks. Connect the probes to each terminal of one of the capacitors, such as C1. This should be an open circuit, not a short.

The picture below shows what a completed SC143, ROM module should look like.

Bus connector

Fit and solder the bus header pins P1.

IC sockets

Fit and solder the IC sockets.

Be sure to fit them with the notch matching the legend on the circuit board, so you do not end up fitting the IC the wrong way around too.

Capacitor 100 nF (0.1 µF)

Fit and solder capacitors, C1 and C2.

This capacitor can be fitted either way around, as it is not polarity dependent.

The exact value of this component is not critical. The use of very cheap capacitors within the range of about 30 to 200 nF is acceptable.

Headers (straight, single row)

Fit and solder the pin headers JP1, JP2, and JP3.

These header pins may need to be cut from longer strips using wire cutters to cut the plastic.


Remove any solder ‘splats’ with a brush, such as an old toothbrush.

Visually inspect the soldering for dry joints and shorts.

Clean the flux off with suitable cleaning materials.

Visually inspect again.

Quick Tests

Repeat the check made earlier for a short. A good place to connect the probes is illustrated below. This should be an open circuit, not a short. If you are using a digital meter set to measure resistance it will likely take a few seconds for the reading to stabilise as there are now capacitors on the power lines. A reading of more than 100k Ω (100000 ohms) is acceptable.

Integrated Circuits

Insert the integrated circuits into their sockets, taking care to insert them the right way round, as illustrated below. Be careful not to bend any legs over.

Getting Started

Jumper shunts will need to be fitted to JP1, JP2, and JP3 before the module can be used. Start with the shunts fitted in the positions shown below. Further details can be found in the User Guide.

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Other information about SC143 can be found here.

Homebrew 8-bit retro computing