First of all you need to acquire a suitable wire / pipe detector, an ideal candidate is the Draper tools model that is available from large Asda stores for around £6.95.

Remove the cover and you will see the ferrite rod with the coil windings, this needs to be carefully removed paying special attention not to cause any damage to the coils or the wires that connect the coil to the circuit board

Once you have removed the ferrite rod you need to remove the circuit from the casing, this is achieved by applying slight pressure to the retaining clip to the left of the thumb wheel. Now gently maneuver the board from the casing.

Once the circuit board is removed you will see a green wire soldered to the board, either cut this as close to the board as possible or desolder it from the board.

The other end of this green wire is connected to a piece of brown PCB that is stuck to the casing where the ferrite rod was, this wire and pcb can be removed, this is to do with the voltage sensing part of the detector and is no longer needed. Also break off the plastic tab that held the ferrite rod in place and remove any excess glue etc.

Now we need to unsolder the ferrite rod from the circuit board, you will notice that there are 4 wires, 2 red and 2 gold, you now need to make a note of which wire connects where on the circuit board, once you have done this take a soldering iron and unsolder the wires.

You now need the lengthen the wires on the ferrite rod by soldering 4 wires to the ends of the coil wires, for now add approx 15 cm extensions. Then using insulating tape, insulate each solder joint.

You now need a piece of plastic tube approx 16 cms long and with an internal diameter of 12/13mm, thread the extended wires and the ferrite rod into the tube, note the end of the ferrite rod with the coil on is the sensitive end so this must be at the very end of your plastic tube. The wires don’t have to come out a side hole like in the pic, they can come straight out the end of the tube. Whilst supporting the ferrite rod gently pull the wires until the ferrite rod is just inside the tube, now would be a good time to glue the ferrite rod in place

Now you need to drill a hole in the detector casing the same diameter as the plastic tube, once you have done this thread the wires through the hole and push the tube through and glue the tube in place, I use a glue gun for quickness but any strong glue will do. Now using the notes you made resolder the wires to their respective places on the circuit board and carefully replace the circuit board back into the casing. Use a small amount of glue to seal the area where the tube enters the casing.

Now all you need to do is seal the external end of the tube you can either use heat shrink sleaving or insulation tape

Now pop in a battery and replace the casing cover and you are finished, you now have a cheap altenative to those commercial probes that will perform just as well ☺