4QD - DC Motor Control

Service, repair, and technical information

Warranty repairs

All controllers are covered by a warranty against defects in manufacturing for one year from the date of purchase.

For any repair under warranty we need:

Please note:

Out of warranty repairs

We offer a fixed price repair service for our controllers see here for a full list of charges.
We try to hold parts for older controllers, but it is not always possible. If a controller is over 5 years old, it may be uneconomical to repair it. If you return it for test/inspection, there will generally be a handling charge for assessing it.
We aim to process out of warranty repairs within 14 days of receipt, although at busy times it may be longer than this.

DIY repairs

It may be that you are technical enough to repair equipment yourself, and that you wish to do so: if so, tell us. Be warned though that, whilst DIY repairs won't automatically invalidate the guarantee, 'inexpert' repairs will. Also, any attempt at DIY repairs will almost certainly remove anything that could have enabled us to diagnose the original cause and if we can't tell what caused the failure - it's not under guarantee.

Returning equipment

All Countries

European Economic Community

No special paperwork is needed - other than the green customs sticker.

Non EEC Countries

Customs and excise in all countries are a problem: UK is no better and if you are returning things, they will have to pass through customs inspection.

All goods imported into UK are subject to import duty, VAT and handling charges. If the British customs do not know that the equipment was manufactured in England and is being returned for repair - then they will make a charge.

Therefore if you are not in the EEC, it is very important to mark the parcel and any paperwork

Faulty equipment of EEC manufacture, for repair. No commercial value

You will need to fill in a customs form: declare the goods truthfully as, for instance, Motor speed controllers. You will probably have to declare a value - but clearly as the goods are faulty, the value is nominal only, maybe 2% of their listed price.

DO NOT declare their value as being the price you paid: if they are dud, then clearly they are not worth this much. If you tell an untruth on the paperwork - UK customs may think this is the true actual value and may charge you appropriately!

Failure to do this may cause the UK customs to add on a heavy charge - which we will have to pay and charge back to you.

Some countries may also have customs 'temporary export' forms. Certainly South Africa does (P.T. 619 - 1986/87). Filling one of these in should speed the incoming customs clearance of the equipment when it is returned to you.


Make sure the carrier you use is fully pre-paid. Some carriers add on a customs clearance handling charge, even when no customs duty is levied.

Return Address

The address to which to send any returns is:

Spare Parts

All of the components we use in our controllers are very common itemas and are available from many different sources.
4QD Ltd. do not generally sell spares other than Replacement MOSFETs) and relays (though you are welcome to email sales to enquire).

Modified Equipment

If there is evidence that the equipment has been tampered with, repaired by non-approved or by inexpert persons or modified in a manner not agreed by 4QD, then it will be considered as being 'modified' and 4QD reserve the right to refuse to service it.

This proviso particularly applies to any mechanical modification such as removing power terminals or soldering to them: boards thus modified will not fit our standard test equipment and cannot be serviced.

Note that the presence of instructions or information on this site (or elsewhere) concerning the equipment or modifications to it, does not necessarily constitute 'permission' to modify it.

Further repair and fault finding information

More detailed and model specific repair information is given here.

Page Information
© 1998-2015 4QD/4QD Ltd.
Page's Author: Richard Torrens
Document URI: /serv/index.html
Last modified: 2015