Often the causes of electronic failures are not electrical at all. The environment on a small sail or power boat requires mechanically robust, rugged construction and many instruments are simply not built with this in mind.

PBO’s back to basics boat electronics repair guide

The prolonged broad-spectrum vibration produced by a marine diesel, the shock loading from slamming into green seas, wide thermal swings from engine or environmental temperature changes, or a simple salt water leak can all result in failure.

Corrosion and motion – inevitable aboard a boat – are major enemies of printed circuit boards and soldered joints.

Often when something goes wrong we think the instrument has reached the end of its natural life: sometimes it has, of course, but equally the fault may be easily diagnosed and rectified so long as we are bold enough to take the back off and have a close look at what’s going on inside.

How I fixed an Autohelm 4000 and a Garmin GPS 152

Top electronic repair tips

1. Even if the item’s manufacturer has stopped supporting your product, it’s worth calling them. Their engineers are often happy to give advice on common problems.

2. Use a magnifier. Electronics components are often tiny surface-mount components and the tracks on the circuit board can be less than a millimetre wide. A lens helps find the problems.

3. Hold printed circuit boards up to the light to look for damaged tracks.

4. Beware of connector pins that have become dislodged (perhaps as a result of your investigations). Check that pins will mate with their sockets.

Reassembling an old Autohelm 4000: the pin indicated by the pen has pushed back into its housing. It’s possible that it won’t make contact when the housing is mated with the circuit board.

5. Wiggle connectors. It’s amazing how many problems can be solved just by wiggling (or better, unplugging and re-plugging) connectors; not just external connectors but internal ones too. The best type of connectors are gold flashed (plated) since these do not tarnish, but even these can give problems.

Wiggle connectors by moving them gently with your fingers in the same axis as you would connect and disconnect them. Don’t wiggle them backwards and forwards, you may do more damage than good.

6. Wiggle ‘silicon chips’ – they’re nothing to be afraid of. It’s unlikely that chips will be mounted in sockets, but if you find one that is, just tweak it gently with a toothpick or something similar. Even a tiny movement will remake the contacts on the pins. Then press it firmly back into its socket. Static electricity can damage sensitive electronic components, so avoid completely removing silicon chips and touch a grounded object to discharge static before working on a circuit.

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7. Take careful note of what screws go where. I know it sounds trivial, but it can be important to ensure the right screw goes back where it came from. Length can be as important as diameter: too long a screw can cause distortions that may lead to problems.

8. Use a fine-tipped soldering iron. Fine-scale electronics needs a fine-scale iron. Buy one with a temperature controller – they’re not expensive.

9. Add additional support to the larger components by bedding them on silicone adhesive (buy the correct stuff from an electronics company – don’t use bathroom sealant). This is often how equipment is ‘ruggedised’.

This little computer lives inside the engine compartment – not the most benign environment for electronics – and one of its power supply capacitors had shorted. I replaced the capacitor and used silicone to support all the components that otherwise would only be held by their wire legs. It looks messy, but will help them withstand vibration and shock loads.

10. Never operate on a circuit with the power on. This is not a question of getting an electric shock – which won’t happen at 12V – but the soldering iron tip is grounded and if you inadvertently touch a component or track with the full voltage you can get an immediate and potentially catastrophic short circuit which could burn out the tracks or circuit board components.

11. Don’t go prodding with a screwdriver. The odds are that you will scratch or otherwise mechanically damage something important. Use a toothpick or one of those useful wooden stirrers from the coffee shop.

12. Don’t bend or flex a printed circuit board. Modern circuit boards can typically have four or six layers and there’s always a chance of breaking a track or solder joint on any of them if you flex the board.

13. At risk of sounding obvious, do check the circuit breaker or fuse is intact and, if you have a voltmeter, check that power is reaching your instrument before you go taking it apart!

14. In simple terms: if it ain’t broke, don’t fix it.

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This feature appeared in the Feb13 edition of Practical Boat Owner. For more articles like this, including DIY, money-saving advice, great boat projects, expert tips and ways to improve your boat’s performance, take out a magazine subscription to Britain’s best-selling boating magazine.

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