White's Classic II, Sens. Knob Rotates Too Easily !

[ToddB64]

Hi All !

I scan my White's Classic II with the right hand and am having trouble with the Sens. Control Knob rotating off of the set position. Guess I'm slightly touching this knob, either as I scan or slide my arm out of the arm cup to dig a target. I checked rotation of the Disc. Control Knob and it seems to have slightly more drag/resistance than the Sens.. I've read that installing a rubber O-Ring under a control knob to add resistance helps to mitigate this problem, but don't know if this will work on the Classic II.

Looking at the Classic II Sens.. Knob, I don't see a set-screw and don't want to pry, over-twist or pull on it before getting some advice on how to properly and safely remove this knob. Furthermore, (a) will the O-Ring idea work, in fact, on the Classic II ? If so, (b) does the O-Ring go directly under the knob ? As far as O-Ring size, I could figure this out by trying different rings until finding the right amount of rotational drag.

Anyone ?

Thanks........ToddB64

 

[Jim in Idaho]

Todd, on my TDI I just pulled straight up on the knob, which removed it. I put two roughly 1/4" o-rings on the shaft, and then pushed the knob back on. Occasionally, I have to push the knob on harder to keep the tension right. Other than that, it works.
Jim

 

[Phillip_in_NM]

Had a similar problem with my M6. I wrapped a hair tie (like they use for pony tails) around the base of the knob. Worked great until I sent it in to White's for another issue. They fixed the issue, fixed the knob and even sent the hair tie back with the machine. Love those folks!

 

[ToddB64]

Jim and Phillip,

Thanks for the tips !

ToddB64

 

[Mega]

I use a very similar method of using a 'o' ring on my T2,the knob just pulls off and a small 1/4'' 'o' ring goes on the shaft a treat,push the knob back on and that stops it from being knocked.Most detectors use the same size pots so this method could be used on a wide variety of detectors that have this problem.

Just gives a little extra friction so that the knob is harder for knocks to alter it but still able to rotate it easy for normal use.

 

[Monte]

COMMENT: I don't know how people manage to do it, but I would guess that in over fifty years of metal detecting, using more brands and models than most people in the hobby today have ever heard of, I might not have bumped a control out of position more than perhaps 8 to 10 times. I pamper my equipment, and I don't wear gloves which could cause some handling problems for some people.

CAUTION: Using a rubber 'O' ring or rubber bands or other form of compression to snug up the knob with a little resistance can be helpful, however .... Do not make it too tight of a fit because on several occasions I have seen detectors where people did this, but it was so tight that adjusting the knob put pressure on the nut that secures the potentiometer and loosens it. At times this make for a sloppy control, and it can also result in a misalignment of the knob pointer in reference to the control setting indications. Worse, however, have been the times that it listened the nut and rotated the control causing a short in the circuitry, and at times even a broken wire on the back of the control.

So, if you use this method, only use a light amount of knob resistance and do not make it too tight.

Monte