8" coil acting weird.

[drummerman]

Greetings all.

I am a new-be here and have only been metal detecting for 2 years.
I have a Bounty Hunter Time Ranger with an 8" coil and a 4" coil. Yesterday, I was doing some detecting, and I notice something weird with my 8" coil. When I would get a target hit and change my unit to the all metals pin point mode, it would beep continuously away from the target and stop when I moved it over the target. (backward from what it should do) Later I was testing it and found the coil would not detect aluminum, or similar metals in the all metals mode, but would see the aluminium and such in the normal operating modes.
I tried my 4" inch coil to see it that did the same thing, and it worked correctly, but the 8" still didn't work correctly anymore. It was working fine the day before.
I am assuming the coil went bad and I need to get another one, but wanted to see if anyone else had this kind of issue before buy another coil and find out it's the Time Ranger rather than the coil itself.
Can I take a electronic voltmeter and test the pins? Any certain resistance/continuity numeric readings I can use? Or is there any other kind of troubleshooting tips you can give me to determine if the coil is bad?
I appreciate any help or info anyone can give me.

Thanks
Drummerman

 

[jimjimmyjames]

Is there a coil cover on your 8" coil? If so, is there water between the cover and the coil? Are there any cracks on you coil where dew or other moisture could have gotten inside of it on the previos day? Just covering the basics. If you know the machine is working correctly, then you have already narrowed it down to the coil.

 

[drummerman]

I do have a coil cover and it isn't cracked anywhere nor is the housing on the coil itself. No water or dirt between the cover and coil.

Last night just for the heck of it, I used an ohmmeter to test continuity on the pins. On this forum, "Inside the 4" BH nugget coil Posted by: Ed in SoDak" (thank you Ed in SoDak) is a great post to see the coils and connections, so I thought I try it to see what I could find out was wrong with my coil.
Now being a novice with metal detecting, I would think that besides the size of the coils, the continuity or connections and the pins on the 4 inch coil should match the 8"coil. I don't mean the resistance measurement numbers, but whether or not there is a closed connection between say pins 3 and 4, (or any of the other pins.) I would think there should be a closed connection between 3 and 4 on the other coil. Both coil pinouts should be the same.
What I found was that on the 8" coil, the one that isn't working right, there was a connection between pin 1 and 5, but I read an open circuit between 1 and 5 on the 4" coil. Except for those two pins thhe rest of the pin configuration matched on the *" and 4" coils, so I am wondering if there is a short between those two pins in the 8" coil somewhere between the coils in the plastic housing and the plug to the metal detector.
I suppose the problem could be where the connection cable enters the coil head itself, but I cant tell if there is a crack on the insulation and any wires touching at the point unless i take apart the search head.
I have many times seen a short development in wires where there is a allot of bending going on other electronic devices.
Personal stereo headphones where the wires connect at the input jack is notorious in having this issue.
I am going to take the 8" coil apart to figure it out what the issue is and will update you guys on what I find out.
I am purchasing a 10" Super Magnum Search Coil. (since I do need another coil) I will check pins 1 and 5 on the new coil when I receive it and see it there is a connection between 1 and 5 on that one.

I was just wondering is anyone else out there has a similar issue with any of there coils.

 

[#1RAMROD]

BH may replace the coil for you if you do not tamper with it first. I would check with them before I did.

 

[Ed in SoDak]

I show no continuity between pins 1 and 5 on either of my 4" or 8" coils.

In the 4" coil, pins 1 and 2 are the green-wired coil, while 3 and 4 make up the two-section red-wired coil plus capacitors. Pin 5 is the "null" or tickler coil and has only one connection. I presume the 8" coil is designed similarly. Actual resistance/inductance/capacitance readings are not identical between the 4" and 8" coils, and also vary slightly from one same-sized coil to the next.

With its web design, the 8" coil would be almost impossible to open up. My guess is your problem will be at the connector end, anyway. I just went to an electronics store and bought a metal din-5 male connector and installed that. No problems since, and it's more secure than before. I didn't need to change the female connector in the main housing, just the male one on the cable.

All the info is here: http://www.whiteriverprep.com/vintage/ArticlesTipsAndTech/bhtech.html

-Ed