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39/ Appendix II: Contact Spray
It’s the boon of the new pulse hunter that many of the high performance machines have the vital design flaw that they need to be opened for every battery change. This exposes the electronics to the elements and the operator to the possibility of a re-sealing mistake. I’ve done this recently even after having written about proper procedures in two of my books. It only takes a moment of inattention and you are looking at a flooded machine. I’ve also written a bit about emergency procedures to take in such an instance but neglected to mention one highly effective remedy. In “Pulsepower…” (2009), I wrote about how to rinse and dry a board that has had contact with salt water--basically a “lifesaving” procedure. What I did not mention is that the most common after effect of a flooded detector is that water gets into the potentiometer (controls or “pots”) making them perform erratically. For example, the threshold may tune low (too loud) or too quiet. This can be very annoying when you are used to tuning your machine in a very precise way for a particular set of conditions. These kinds of faults have caused me to send in machines several times--when there was actually a very simple solution--contact spray.
Condensation can reduce the performance of potentiometers over time. While this may appear to be a serious problem it can often be solved by applying contact spray as shown. This remedy will also restore accurate control functioning after a leak.
Contact spray is a product available at any electrical supply shop that acts to clean and dry any conductive surfaces in an electrical device. It’s also handy for finishing up a rinse in that it dries in a few minutes--taking any moisture with it. For a potentiometer, use the red applicator tube and direct the spray to the venting at the back of the pot. As you do so, turn the pot to full range and back a few times rapidly. This will ensure that the spray is getting to all of the contact surfaces. This simple fix will bring most pot problems into correct functioning. If there continues to be problems (“dead” spots or single setting only operation) this would likely mean that current has caused the contact surfaces to fuse or burn and the control needs to be replaced. Contact spray can also be used to periodically “touch up” a printed circuit board when you notice any performance changes (which is not to say that this will be the definite solution). Be sure to allow for a long and thorough drying period before putting any power though the machine though. Using a fan or low temperature hair dryer is not a bad idea--to make sure that no spray residue remains in any recessed areas of the board or pots.
Another use for this product is to restore a co-axial jack that is intermittent. These jacks draw dirt and moisture--affecting their functioning over time. The pins and sockets of “Ikalite” plugs may also require this periodically. (Be sure to touch up the insides of the sockets with a “rat tail” file before spraying). Contact spray cleans them and restores current flow.
More generally, I highly recommend that if you are serious about the detecting hobby you take the time to learn anything you can about basic electronics. Just watching a skilled tech undertake a repair can help you to understand and possibly fix minor future detector problems. On the other hand, never undertake a repair that is beyond your abilities. Things like soldering to a PC board or working with co-axial cable braids are best left to the experts. It’s better to pay and have something done properly than to risk anything from ruining a machine to just not having it operate properly in the field.
From: "Advanced Shallow Water Metal Detecting: Tips, Tricks and Methods for the Shoreline Treasure Hunter"
by Clive James Clynick
clivesgoldpage.com
It’s the boon of the new pulse hunter that many of the high performance machines have the vital design flaw that they need to be opened for every battery change. This exposes the electronics to the elements and the operator to the possibility of a re-sealing mistake. I’ve done this recently even after having written about proper procedures in two of my books. It only takes a moment of inattention and you are looking at a flooded machine. I’ve also written a bit about emergency procedures to take in such an instance but neglected to mention one highly effective remedy. In “Pulsepower…” (2009), I wrote about how to rinse and dry a board that has had contact with salt water--basically a “lifesaving” procedure. What I did not mention is that the most common after effect of a flooded detector is that water gets into the potentiometer (controls or “pots”) making them perform erratically. For example, the threshold may tune low (too loud) or too quiet. This can be very annoying when you are used to tuning your machine in a very precise way for a particular set of conditions. These kinds of faults have caused me to send in machines several times--when there was actually a very simple solution--contact spray.
Condensation can reduce the performance of potentiometers over time. While this may appear to be a serious problem it can often be solved by applying contact spray as shown. This remedy will also restore accurate control functioning after a leak.
Contact spray is a product available at any electrical supply shop that acts to clean and dry any conductive surfaces in an electrical device. It’s also handy for finishing up a rinse in that it dries in a few minutes--taking any moisture with it. For a potentiometer, use the red applicator tube and direct the spray to the venting at the back of the pot. As you do so, turn the pot to full range and back a few times rapidly. This will ensure that the spray is getting to all of the contact surfaces. This simple fix will bring most pot problems into correct functioning. If there continues to be problems (“dead” spots or single setting only operation) this would likely mean that current has caused the contact surfaces to fuse or burn and the control needs to be replaced. Contact spray can also be used to periodically “touch up” a printed circuit board when you notice any performance changes (which is not to say that this will be the definite solution). Be sure to allow for a long and thorough drying period before putting any power though the machine though. Using a fan or low temperature hair dryer is not a bad idea--to make sure that no spray residue remains in any recessed areas of the board or pots.
Another use for this product is to restore a co-axial jack that is intermittent. These jacks draw dirt and moisture--affecting their functioning over time. The pins and sockets of “Ikalite” plugs may also require this periodically. (Be sure to touch up the insides of the sockets with a “rat tail” file before spraying). Contact spray cleans them and restores current flow.
More generally, I highly recommend that if you are serious about the detecting hobby you take the time to learn anything you can about basic electronics. Just watching a skilled tech undertake a repair can help you to understand and possibly fix minor future detector problems. On the other hand, never undertake a repair that is beyond your abilities. Things like soldering to a PC board or working with co-axial cable braids are best left to the experts. It’s better to pay and have something done properly than to risk anything from ruining a machine to just not having it operate properly in the field.
From: "Advanced Shallow Water Metal Detecting: Tips, Tricks and Methods for the Shoreline Treasure Hunter"
by Clive James Clynick
clivesgoldpage.com
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