Would Dielectric Grease Interfere With A Radio Signal?

What is the antenna configuration? Is it part of the PCB or is it part of the case? Is the connection loose, or now having a conductivity path that attenuates the RF input signal? Most of the circuitry is a voltage multiplier I'm guessing diodes and capacitors in cascaded voltage doublers with a push-pull driver. Most likely a single chip RF receiver with some sort of signal detector. As it's working the antenna/RF receiver input must have signal loss. Spraying this with engine starter fluid should be safe to removed the grease, and maybe remove any hidden salt film.

It's a small spring type RF antenna, similar to this.

I didn't anticipate that the grease would cause any interference, so I generously coated everything. Further cleaning won't be difficult, but I'm still curious as to whether the, (non-conductive), grease would hamper a radio signal from reaching the antenna.

GA. Turned out to be an interesting thread. I had always assumed that dielectric grease was completely benign, as far as electrical fields go.

I'll test the range today; it was raining hard, yesterday PM.

I agree. Perhaps tuning capacitor are filled with new material and frequency drifted apart a bit to edge. Was there any variable capacitor on board?

Now that you have fixed it or replaced it, put it on and give the remote to your daughter.

No. It's not conductive.

My uneducated guess is that the salt water degraded something else in the reciever circuit.

I hate it when something "sort of" works.

I rinsed out the salt water immediately, and dried the unit with a hair dryer. The entire PCB comes out.

...and you replaced the batteries in both the collar and sending unit with fresh ones right?

New battery in sending unit. The battery in the collar is soldered in and rechargeable.

It shows a full charge on my tester.

Salt water will destroy any electrical device....unless it is sealed...

He was scared of the ocean, but he couldn't resist the stinky black mud in the creek we were staying on. The collar still works fine; I've just got diminished range.

He's beginning to forget his boundaries in our yard, and needs an occasional reminder.

The dummy thinks cars are like Christmas presents, and contain people that might want to rub his belly.

Ha...

That's about what he looked like; and he started off white.

I just took the collar off and let him play in the mud every day.

This is interesting:

What are Dielectrics?

There are two general types of matter (substances) in the universe that affect electromagnetic waves, conductors and insulators which are called "dielectrics". Majority of them except some conductors are metals, such as copper, aluminum, silver and gold. Nevertheless, salt water is also a rather poor conductor. Pure water is a good dielectric substance. Most, but not all, dielectrics are non metals. Examples of dielectrics are paper, plastic, Teflon, glass, ceramic and dry wood. As the radio wave travels through the dielectric material, some of the power is absorbed generating heat and some of the power travels through and comes out of the other side.

From here:

http://www.innovateus.net/science/how-are-radio-waves-blocked#What+are+Dielectrics%3F

Perhaps the dielectric grease is converting a bit of the radio waves into heat, reducing the signal.

Well, hose it down and give the controller to the daughter. Make her day!

I glopped it on there pretty good. now I have to find a solvent that removes silicone.

Toluene/acetone/MEK in that order, I think.

Those might work, but they also tend to melt plastic.

Hey! You didn't ask for non-plastic eating solvents.

Toluene is less aggressive to some thermoplastics than the others, but you're right.

You have probably added parasitic capacitances throughout the circuit, and they are loading down your signal. perhaps a good conformal coating would have been better, but check the specs on added capacitance there as well.

It's cleaned up. I just have to wait for the dog to take off, or my daughter to get home from school, to see if it works.

BTW- The internet advice that says to use denatured alcohol to clean dielectric grease, is BS.

I used a liquid silicone lubricant from a can, to blow off the bulk of it, and followed with carb cleaner.

Carb cleaner, yikes, that stuff will eat most plastics! Go to Radio Shack and buy tuner/contact cleaner or get some CRC electric contact cleaner (02130, there are others) and spray everything off. Hopefully the carb cleaner didn't dissolve anything critical.

Too late. I already did it.

Fortunately, it was a new brand of carb cleaner, (for me), and evaporated very quickly...almost like starting fluid.

The collar is still functioning, I just need to do a range check. I leave to pick my daughter up from school in a couple of minutes; I'm sure she'll be happy to stand on the front porch and shock me as I walk away from her.

I just need to make sure she only hits #1. It's got 6 strength buttons, with 6 being the highest charge. I'd rather not end up crapping on myself.

Sounds like your granddaughter has you already trained for retirement.

Then again, with all that power, she may want to take over the world!

To your original questio, it depends upon which dielectric grease you used, hopefully yu can get it all off. Some dielectric greases are a misnomer since they are used on contacts and current carrying parts to both keep them dry but conduct when they are on mating surfaces, often for static control purposes; i.e., they are high ohmic conductors that will carry static voltages while limiting the discharge current. Something like that will probably attenuate an rf signal.

The bigger question is if you got all the saltwater out, as others have noted salt is nasty stuff as far as corrosion goes, and anything that bridges across contacts and unprotected pc board traces may have unseen consequences. That said, the fact that the device still works is a good sign, just make sure the whole thing is squeaky clean and free of any grease.

Kramarat-

When something electronic gets a salt water "bath" a good start for drying it out is to give it a good fresh water bath (rinse not submerge) before anything else. The fresh water dilutes the salt content and there for reduces the conductance, corrosion due to the sodium, penetration into parts by the salt water and will lubricate somewhat compared to a half dry salt water contaminate. Depending on the components a good gentle shot of compressed air or the compressed gas duster for keyboards could be a good thing to do.

In the meantime before drying, try to make this a short interval as possible.

With the fresh water rinses, you are not evaporating the water and leaving residual salt behind.

After drying pack it in a plastic bag in white rice. This will get it to the driest possible. Don't ask me why, I wouldn't believe it until I saw the results! After the rice bath remove it from the bag and give it a gentle clean air/duster shot and try to use it.

Much to my disappointment I have had to follow this procedure more than I want to count. Most often it works. I have found that the cheapest things are the hardest to resuscitate.

Good Luck, Old Salt

I'd add one more step.

After soaking in warm water, rinsing and soaking again, I'd then rinse it in isopropyl alcohol, a very common cleaner for electronic circuitry. Then sling it around your head so centrifugal forces extract most of the IPA, THEN blow dry.

Thanks old salt. That's what I did, minus the rice...but I'll keep that trick in mind. I used a hair dryer.

After drying pack it in a plastic bag in white rice.

Yep, Anyone living in a humid climate will confirm that a few grains of rice in a salt shaker keeps the salt flowing freely. Absorbs the moisture from the salt. Common practice.

The ability of rice to act as a desiccant is highly overrated.

The grains of rice in a salt shaker perform the same function as the iron balls in a ball mill. Thy break up clods and clear the shaker hole as they impact the cap...sometimes. One still has to resort to opening the shaker to get to the salt more often than not.

I never throw away the dessicant pouches I find in some packaging. I store them in a sealed dry container, after heating them in the sun if in doubt as to whether or not they are truly dry, ready for just such emergencies or for chucking into stored tool boxes or bags of dry goods (eg cement, plaster, caustic soda...) to prolong their shelf life.

It is humid here.

Wal-

As I stated: Don't ask me why, I wouldn't believe it until I saw the results! Results are still the same.

Good Luck, Old Salt

You have a smart dog!

Yeah. He's so smart, he's going to end up getting his a** beat.

He won't leave the yard while we're home, but when I get home in the afternoon, he's been up in the neighbor's field, wallowing in fresh horse poop.

He's just about trained, but he's been slipping since the collar stopped working.

We'll get there. I don't believe in keeping dogs tied up or penned all day long. He's got over an acre that he can roam around on.

Unfortunately, most stuff nowadays is cheaper to replace than repair, especially if it's been exposed to salt water.

Yeah, but in the case of these collar units, they have a bad reputation anyway, so a replacement probably wouldn't last much longer.

With the nonfunctioning original, I have a starter kit, and for probably less than $10 worth of components, I can make one that I can depend on.

Still no range.

There's not much to the PCB. Hopefully Radio Shack has the components to rebuild it.

In addition to those earlier sensible comments, when dealing or working around those coiled, or spring looking wires that are part of the circuit(s), bear in mind that the spacing between the coils are very critical in RF applications.. What they called as stray, parasitic capacitances are or will be greatly affected (altered) when the physical configuration of that said coil(s) are changed.. and therefore will negatively affect by degrading the circuit's performance. Akin to changing the dielectric constants of a particular component...

Good luck

That's a possibility. These are also cheap Chinese units that get bad reviews for early failure. Assuming I can get the components, I should be able to rebuild it in a couple of hours.

I see no reason why it cannot be fixed.. specially if you have an oscilloscope to use..

It is necessary to see the waveform when adjusting the frequency of the tank circuit.. to enable one to peak its resonant frequency and to maximize the power transfer to the pickup coil.. also to match and tuned to the receiver's frequency..

Good luck!

This is true and it becomes more and more significant as the frequency increases.

How's that toilet flushing?

Things like dog collars (most consumer electronics _{and cars}) are not built to be repaired. Surface mount technology is great for manufacturing efficiency, but suck for repairability.

Go ahead and let us know how this repair works out.

For best results, do this before "the sun is over the yardarm".

I have to go take my pool pump apart and clean the impeller now.

I think I've figured out the toilet, but I haven't torn it back apart again.

I'm pretty sure that when the 1.6 gallon flush rule came out, American Standard attempted to do it completely with the guts in the tank rather than designing a new toilet. The hole in the bottom of the tank will fit a 3" gasket and flapper, and it's much smaller than that now. I just need to order the larger diameter flapper online. Nobody carries them in stock.

I bought the cheapest toilet HD sells. It was the only one they had that would fit in the original space. (too short for a "normal height" toilet) $148.00 USD. (Kohler^®brand)

The BEST TOILET I've ever flushed! Ever.

Pump is fixed, too. Only took me 30 minutes. First time I've taken this "new" pump apart. Piece-o-cake.

I agree; in many RF applications they affix the coil shape using wax, so I doubt the grease affects the range that much, I think it was the salt water which bridged current to where it should've not, thus degrading a component due to overcurrent; not that the water carried all that current, but probably caused an increased signal at a base or a gate or an input of an amplifier causing it to overheat and half die.

I would replace the output transistor first, if accessible.

I'ts true and possible that Mr. Kramarat's range problem can be caused by anything that may be capacitive in nature. The degraded pickup range can either be due to sensitivity or lack of transmitted power? Either way an oscilloscope will be necessary to facilitate RF troubleshooting. Without it, is just like shooting in the dark..

I'll be shooting in the dark, but I didn't bend or tweak the spring antenna. I think it may have more to do with the salt water than the dielectric grease.

It may possibly be true as you claimed, but by having the scope in my experience, especially when dealing with any RF related issues makes one's life a lot easier. Greatly minimizes errors as well as to validate your suspicions. It basically just provide the user with an immediate visual feedback, indications on the cause and effects as changes are made..

Good luck..

vsar

That's true only of you know what the squiggly lines on the screen mean.

I don't. Gotta depend on blind luck.

There are specific points inside circuits like the one of your device, that an ever so slight change in capacitance due to a dielectric different than the specified (air), will also slightly change transmitting and/or receiving frequency, and this applies on some degree even on crystal or PLL tuned circuits. Now that frequency drift will directly affect the usefull range, and that I think happened here. You can seal a board from humidity and dirt with various substances but critical parts of the board must not get soaked. S.M.

Yeah. It was less than $30 from Amazon, and the reviews are filled with early failures. I'm sure the water and my grease treatment didn't help.

I'll attempt a rebuild and post the results.