Remove the coil if it is not attached to the circuit.
Note: Some watches need some of the wheels disassembling before the coil is able to be removed. On these, remove the dial and movement and place in a movement holder. You may need to remove the hands
If a replacement coil is available REPLACE IT, it is the best repair.
Look down the length of the coil on all sides for bright copper colour, discolouration of the coil or anything that does not look right.
The break in the coil is usually at the point where you see the anomaly. Shake the conductive paint until it is thoroughly mixed. Dab a small amount of paint on the area you suspect is the break and then wait for it to dry.
Look for loose wire: With a high power eyeglass (12x or more), look carefully where the wire is. You will never get it back to where it broke, so unravel 1 turn of wire. Break off the excess and dab conductive paint over area. 2 or 3 layers of paint are usually needed as the unraveled wire does not sit perfectly flat.
tip: a minute drop of nail varnish remover loosens the varnish of the coil to ease unraveling. Allow it to dry before applying conductive paint.
With a high power eyeglass (12x or more) check the 2 wires from the coil to the circuit are OK.
There are 2 wires that can be broken. One is quite easy to repair and the other is almost impossible.
The easy wire to repair is the wire to the top layer of the coil.
- Using a fibreglass brush, very gently remove the varnish from a small area of the coil a quarter of the way down on the side. Dab conductive paint to the area and when it is dry, test with the circuit tester to check the resistance form the conductive paint to both contacts. If one contact is between 1.5ohms and 4.5ohms and the other contact is much too high then the coil is repairable.
- Solder a new piece of wire to the contact.
Tip: to harvest wire from an old coil, cut metal loop off the end then soak the scrap coil in nail varnish remover. While coil is in the nail varnish remover, pull one of the wires of the top layer off and it should unwind easily.
- Wind 1 turn of new wire around the coil too where the paint is, being careful not to break the other wire. Use the soldering iron to remove the varnish and tin (add a layer of solder to a wire)the new wire where the paint is. (Do not solder on the coil.)
- Use the excess wire to hold the new wire in place and dab on a few layers of conductive paint to make the circuit.
- When it is dry, test the resistance of the coil to see if it is between 1.5 and 4.5ohms. If it is, glue 2mm of the excess wire to the coil using hypo cement before breaking/cutting off the rest.
Test your coil with the circuit tester if it is OK. Reassemble and check the watch.
If you can not repair the coil and want to remove the conductive pin, dip it in nail varnish remover and gently wipe with rodico.