Excalibur II with threshold issues?

[Dsparil]

Just got an excalibur II off of ebay. Previous owner said was mechanically fine. I took skid plate off and he hadn't cleaned underneath it. Not sure if this might be part of the problem.

Anyhow, what's happening is, I turn on the detector at the threshold knob and right off the bat it gives off a LOUD hum. It isn't until I move the knob half way through that it goes to a minimal volume hum. Between that spot and off it seems to jump from on to off over and over. Once it does hit the minimal point it seems to function as normal.

Now, if I turn the threshold all the way up then try to turn it down, it does nothing for the volume of the hum. Regular volume control works just fine when I run the detector over things like silverware, knives and even a gun lol.

Anyone have this issue before? Could it be the coil?


Oh and if I run the detector flat to the floor it seems to just turn off.

 

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[Treasure_Hunter]

On,off/Threshold knob it should be low threshold when first turned on and gets louder as it is turned clockwise. If you hear more than 1 click after first turning on the knob the potentiometer is bad, it should get louder the more you turn it clockwise and only have 1 click, if it has more than 1 click the potentiometer is bad.

You want the threshold to sound like a tiny mosquito in your ear, too loud it will mask targets, too low you want notice faint/deep targets.

I f you try to run it over a floor that has iron in it such as rebar it will go silent as it goes over the iron, this is called nulling, detector is telling you there is iron/ferrous metal below the coil. Electrical wiring in a building gives off EMI interference and makes detector unstable too.

 

[Dsparil]

Wow thanks. Ok then. How much does it cost to fix the potentiometer? Is that a fixable thing or is it kaput? And now it has more than one click. I can still rock it to where I can adjust the volume, but........ yeah

 

[Treasure_Hunter]

Wow thanks. Ok then. How much does it cost to fix the potentiometer? Is that a fixable thing or is it kaput? And now it has more than one click. I can still rock it to where I can adjust the volume, but........ yeah

It is a simple fix, not sure of current cost on replacing pot, send it in to Minelab service center (Detector Center) and while it is there have them replace all the o-rings and check all pots just to be sure other pots are good.

 

[Dsparil]

appreciate the input. thanks

 

[OBN]

Last I heard it was 110.oo to replace the pot. If you just got it off ebay I would contact the seller and inform them of the issue.

ALSO I would suggest flipping the machine over, take the battery off and look for this..