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LarryF

For SM transmitter users- silver grease

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We are starting to include 25 mg (tiny amount) of silver conductive paste in a teensy vial, with all SM series transmitters. This is to be used on the thumbscrew for the battery cover plate. We have been applying a 1 mg (very tiny) speck of this silver conductive paste to all SM's manufactured in the past year. The reason for the conductive paste is to reduce the slight voltage drop between the thumbscrew threads and the case threads. As this drop is reduced, less battery power is used to overcome this drop and more is available to power the transmitter. As the thumbscrew is loosened and tightened while replacing batteries, the silver in the paste is forced into the microscopic pores in the metal of the threads and improves the conductivity. We recommend cleaning and re-applying the paste every 6 months. Like oil changes, change more often in dusty conditions. Complete instructions for cleaning the threads and applying a speck of paste are included with the vial. We will also send some extra vials of silver paste to our dealers at no charge when requested. For previously purchased SM series transmitters, you can pick up a vial at a dealer. Since one vial will do many transmitters, there is no need to request multiple vials. For those with 25 or more SM's, feel free to take two vials or even three.

For the first few years of production of the SM series, a little bit of white grease was put on the thumbscrew threads. Nobody really knows why except it seemed reasonable. Unfortunately, the white grease is non-conductive and it picks up dust which is also non-conductive. In the worst cases it can reduce battery life by 50%. The first thing to do is to remove the old lubricant with a clean cloth and clean Q-tip. This will generally greatly improve conductivity and battery life just by itself. Then apply a pin head speck of silver paste on the second thread from the end according to the instructions and pictures.

Best Regards,

Larry Fisher

Lectrosonics

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Thanks for the info Larry

This probably explains the mystery I'm having while using my SM transmitters, One day a battery can almost go through a morning, the next day I'm changing batteries every 2 hours....

Is this the same kind of silver paste used on computers CPUs before applying the Heatsink ?

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Thanks for the info Larry

This probably explains the mystery I'm having while using my SM transmitters, One day a battery can almost go through a morning, the next day I'm changing batteries every 2 hours....

Is this the same kind of silver paste used on computers CPUs before applying the Heatsink ?

Hi Eric,

Those are the SM symptoms. Until you get the grease, clean the threads of the thumbscrew. The finish is Teflon impregnated, so lubricant is not very necessary.

The "silver" paste used on computer heat sinks is "misnamed" by the vendor's advertising department. There is little or no silver in the compound and it is non-conductive for obvious reasons.Scam is too strong a word, maybe. The Lectro paste is about 65% to 85%% silver by weight according to the manufacturer and the rest is a silicon oil.

data sheet : http://www.2spi.com/catalog/vac/silver-filled-grease-techdata.html

sales sheet: http://www.2spi.com/catalog/vac/silver-filled-grease.shtml

Best Regards,

Larry Fisher

Lectrosonics

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" The "silver" paste used on computer heat sinks is "misnamed" by the vendor's advertising department. "

that is primarily for heat transfer

" simple dry graphite lubricant would do the same thing. "

" The reason for the conductive paste is to reduce the slight voltage drop between the thumbscrew threads and the case threads. "

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Hi Larry, thank you for the Information!

I was wondering, whether a simple dry graphite lubricant would do the same thing.

Any insights on this?

Cheers

Christian

Hi Christian,

Graphite is much less conductive than silver by orders of magnitude. In truth, we didn't try graphite but the silver worked so well we didn't go any further. Also graphite gets all over everything.

Best,

Larry F

Lectro

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Maybe a small dab of dielectric grease used for spark plugs ? (And other automotive/motorcycle electric components)

Dielectric grease is very much an insulator and that is the opposite of what is wanted here. At room temperature, silver is the best conductor available.

Best,

Larry F

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Speaking of screws on the SM's.....I had to take off the back plate of a SM - the one that's held on by 10 tiny screws. I noticed when each screw came out a small amount of stuff would come out with it, like a light plastic. Larry do you use a liquid plastic substance, like a low grade Loc-tite on those screws? If so, how do I get some to re-apply so I don't loose screws.

Thanks in advance.

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Speaking of screws on the SM's.....I had to take off the back plate of a SM - the one that's held on by 10 tiny screws. I noticed when each screw came out a small amount of stuff would come out with it, like a light plastic. Larry do you use a liquid plastic substance, like a low grade Loc-tite on those screws? If so, how do I get some to re-apply so I don't loose screws.

Thanks in advance.

Hi Mirror,

The back plate is sealed all around the edge with type 2 RTV silicon seal. This is the silicone seal that smells faintly of ammonia with alcohol. You can find this at most all hardwares. It is now hard to find the type 1 RTV (which you DON'T want for electronics). Type 1 can be identified by its strong vinegar (acetic acid) smell. The acid vapors will harm the electronics inside. Make sure it is RTV from GE or Dow Corning or an equivalent full silicone seal. Some other stuff is siliconized which means it is regular old caulking material with some silicone oil added to the mix.

It only requires a very small bead all the way around. 99% of it will squeeze out which is why you only found it in the screw holes.

RTV = Room Temperature Vulcanizing

Cheers,

Larry F

Lectro

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Hi Mirror,

The back plate is sealed all around the edge with type 2 RTV silicon seal. This is the silicone seal that smells faintly of ammonia with alcohol. You can find this at most all hardwares. It is now hard to find the type 1 RTV (which you DON'T want for electronics). Type 1 can be identified by its strong vinegar (acetic acid) smell. The acid vapors will harm the electronics inside. Make sure it is RTV from GE or Dow Corning or an equivalent full silicone seal. Some other stuff is siliconized which means it is regular old caulking material with some silicone oil added to the mix.

It only requires a very small bead all the way around. 99% of it will squeeze out which is why you only found it in the screw holes.

RTV = Room Temperature Vulcanizing

Cheers,

Larry F

Lectro

Ah, thank you for that. Strangely enough, I had to take off the back because I heard something rattling around inside. When I took off the back, an internal screw fell out. Couldn't find where it came from and nothing else seems to be rattling around. The unit works fine so I closed it back up. I was wondering how the unit didn't get swamped with actor sweat but now I know I need to add RTV silicone to protect it.

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My local electronics store didn't have silver grease, but I picked up some conductive carbon grease instead. Seemed to work well for my SMQa but not so well with my SMDa...

I'll be asking my local retailer for a small tube of the silver grease when it arrives...

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My local electronics store didn't have silver grease, but I picked up some conductive carbon grease instead. Seemed to work well for my SMQa but not so well with my SMDa...

I'll be asking my local retailer for a small tube of the silver grease when it arrives...

Should ship out this week. Initially, we will send out what we think is enough and then add to it as asked by the dealers. The tiny vials will also go out with each SM series unit.

Conductive carbon grease is OK for static discharge but not for this application where the voltage drop is less than a tenth of a Volt with half an Amp of current (worst case). To remove the drop, you need less than a tenth of an Ohm of resistance.

Best,

Larry F

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The part number for this vial is SMSILVER, if your dealer needs to request it. The name is bigger than the vial. If you are in Lower Slobbovia, and your dealer is being held for ransom by the Capitalistic Faction, we can send vials from the factory. Usual larryf@lectrosonics.com.

Best,

Larry F

Lectro

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Hey Larry,

Another question about RTV, I had to reseal a SM transmitter that needed to be taken apart and dried out after a dunking. I used the Dow Corning 734 Self leveling silicone that was in the Lectro kit I bought for making waterproof mic connectors for my MM400's.

There is no indication of type 1 or 2 and it smells pretty strongly of vinegar. Should I be pulling that SM apart and replacing the silicone or would the damage be done only in the curing process?

Cheers,

Brent Calkin

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The timing on this thread is incredible! I was noticing last night that my SM doors were needing to be over-tightened in order to form a consistent connection. On two of them, the power LED stays red (I assume from the voltage drop). I searched google for "lectrosonics conductive grease"... and low and behold!

Thanks Larry, I'll try to get my dealer to order some in ASAP. Would one vial be enough for multiple applications on six transmitters? Is the vial resealable, or should I get a backup for future applications?

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Hey Larry,

Another question about RTV, I had to reseal a SM transmitter that needed to be taken apart and dried out after a dunking. I used the Dow Corning 734 Self leveling silicone that was in the Lectro kit I bought for making waterproof mic connectors for my MM400's.

There is no indication of type 1 or 2 and it smells pretty strongly of vinegar. Should I be pulling that SM apart and replacing the silicone or would the damage be done only in the curing process?

Cheers,

Brent Calkin

Hi Brent,

If it smells like vinegar (acetic acid) it is type one and the wrong stuff. You probably are OK and taking it apart needed to be done in the first hour or so. Again you are probably OK. I will get a note put in the kit to not use the self leveling for sealing the backplate of the SM.

Best,

Larry F

Lectro

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The timing on this thread is incredible! I was noticing last night that my SM doors were needing to be over-tightened in order to form a consistent connection. On two of them, the power LED stays red (I assume from the voltage drop). I searched google for "lectrosonics conductive grease"... and low and behold!

Thanks Larry, I'll try to get my dealer to order some in ASAP. Would one vial be enough for multiple applications on six transmitters? Is the vial resealable, or should I get a backup for future applications?

Hi Wyatt,

The vial can do at least 10 units containing 25 times as much as we use at the factory. The vial is resealable. Two vials should hold you for years and we will continue to make it available.

Best,

Larry F

Lectro

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Hi Larry are we in Singapore able to get our share?

Sent from my iPad using Tapatalk HD

Hi James,

We probably are already sending some to your dealer but it doesn't hurt to ask them so they can nag us. In a pinch, we can send you some directly but we'd prefer to just have it available at the dealers.

Best,

Larry F

Lectro

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The timing on this thread is incredible! I was noticing last night that my SM doors were needing to be over-tightened in order to form a consistent connection. On two of them, the power LED stays red (I assume from the voltage drop). I searched google for "lectrosonics conductive grease"... and low and behold!

Thanks Larry, I'll try to get my dealer to order some in ASAP. Would one vial be enough for multiple applications on six transmitters? Is the vial resealable, or should I get a backup for future applications?

Also, cleaning the male and female threads with a clean cloth and q-tips several times will also improve conductivity until you get the silver paste.

Cheers,

Larry F

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