Deben ferrert mark 3

[Guest earthdogfinder]

I have a deben ferret finder mark III - the orange box type , its about 3 years old almost now But the orange box the receiver only works to the short range depth of 7/8 ft now and wont work at all at the 15/16ft range , otherthan sending it to deben whom want £20 just to look at it with out any parts or repairs -- is there anyone whom knows anything about these and to rectify this problem without having to contact deben ?

[PETEWINN 5]

Does moving the search \ locate slider make any difference to the depth?