You can find a break in a underground dog or pet fence by turning the raido field on the transmitter up all the way.(take receiver off pets first)and remember where the dial is set so you can set it back to the same setting when you are done.After setting the field up all the way use a am walkman and set the am dial as low as it can go.The easy place to start is the driveway because in most cases you can see where the wire crossing is.Next hold the walkman near the wire and you should hear a feedback.Next follow the feedback till it fades to nothing and you should be near the break just dig up the wire and tug it should come loose.Next pull out the slack and stretch it out to find the distance of the other side.Splice the two together and seal water tight and thats it.
(this may not work with all systems but most of them should not be a problem)Should this not work follow these directions
1. Go to Radio Shack and by RF choke catalog #273-102
2. Disconnect the 2 twisted wires from the transmitter and and wrap them around the choke one on each side.
3. Connect the choke with the wires attached into the transmitter (same as where the twist was removed)
4. Plug transmitter in.
5.Follow directions above.
When useing the RF choke you may need to adjust the signal field lower for small yards and up for larger yards.Also try adjusting the am radio between am530 and am600. Good luck
Thanks for reading see more dog fence repair tips here http://www.dogguardnorthwest.com/dog-fence-repair-tips/how-to-find-a-break-in-a-underground-dog-fence