Static noises from new scratchplate .

[Len Biglin]

Hi Guys , I have just installed new "F" custom shop pickups on a strat copy, using a new "M.O.T.S."scratchplate.The thing crackles and ticks like its alive , I have checked all the wiring , and the plate has an alfoil shield/ground plane over the whole area of the pickups and controls.I have checked that its grounded to the pots etc. and it is all working tho I haven't strung it up yet.I have seen this before but not when the whole thing has a foil shield, Any ideas? thanks Len

[Tim Mace]

Sorry I can't help you but wtf is M.O.T.S.? Mother Of Tungsten Steel?

[Ned Knepp]

Tim,
Mother Of Toilet Seat.

[Donald A. Fortune]

Hi Len - Did you put a ground wire to the bridge?? And sometimes but not always you may need to string it up
and go from there- just my two cents...
Peace,
Donald

[Russell Vance]

Len, I have just had to ditch a Tele plate for the same reason - a new plate from a different source coupled with a full aluminium EMP tape treatment to the back of the plate with the back of the plate earthed to the control plate/electronics package worked OK in this case ...but I have seen a number of these things lately and they seem prevalent in recent MIM (made in Mexico) Fenders.....The Teles have been the same, and both of them had the thin single ply white guards - rubbing ones finger over the plate (particularly above the neck pickup wiring channel creates a very audible scratching sound - static discharge basically. I suspect the composition of the pickguards may have changed and may have some thing to do with this - I recommend you tape the back of the plate, earth it to the control plate/instrument earth and not check it out in a dry environment with nylon carpet.

[Joshua Levin-Epstein]

Russ is correct. A customer of mine had a recent G&L telecaster type that mad noise like a bowl of rice krispies. I shielded the back of the pickguard, grounded it & that awful static ring was gone.

Plastic of most any kind draws static noise.

Joshua

[Len Biglin]

Thanks for those ideas everyone, Rusty what is EMP? electro magnetic .....? and did you note that this guard has Alfoil tape over the area of controls and pickups ?I will string it up today and keep you all posted . Len

[Len Biglin]

OK I found the problem, the shield was made up of two strips of wide Alfoil tape , one covering the control area and one over the pickup area , the two overlapped but weren't connected electrically (when touching one the noise got louder) so I ran a strip of copper tape over the join and all's well . Thanks again Len

[Russell Vance]

yep, Len I did note that - EMP Tape is the high quality relative of the copper shielding tape - it's just aluminium foil with a conductive adhesive and the reason you put it all over the back of the guard is to provide the shortest static earth path possible and other such voodoo explanations etc...EMP is just a nickname (electro magnetic pulse) - if you you are subject to a nuclear explosion generated EMP you can rest assured that static on your pickguard is the least of your worries!

[Rob Mercure]

So what does the "EMP" refer to in the tape (I think of electromagnetic pulse as "EMP" also and am old enough to remember the "duck under your school desk and kiss your ass goodbye drill of the early '60s also).

Rob

[Russell Vance]

Rob, the tape is used to shield, via what is known as a Faraday cage, sensitive electronics from the inductive part of an electromagnetic pulse generated by a nuclear blast (in laymans terms this .....the nuclear physicists reading this will take me to task I'm sure).....that way your TV's vital electronics may survive a 10 megaton hit at the bottom of your garden. I've seen movies of people ducking under tables (usually set in shady establishments when their wives walk in).

[Rob Mercure]

Rusty,

I'm quite familiar with faraday cages and did a lot of research on EMPS when Reagan was pulling his "stars wars" scam for ABMs (which to this day still haven't hit a target where the launch location and time wasn't known - many billions of wasted dollars). So I probably know the tape by some other name - probably simply "shielding tape." Your probably aware that the shielding of electronic equipment is referred to as "hardening" but as far as I know vacuum tubes are still the only communications technology that is "guaranteed" to be able to stand an EMP - semiconductor junctions fry fairly easily. During the late 1970/early 1980s a Soviet defector flew a MIG-25 into Japan and the American press made much that is still used "backward" vacuum tube technology. It actually took a while for the establishment to realize that the MIG would keep flying after a nuclear attackw while our semiconductor dependent aircraft would fall from the sky!
A bit of trivia: Despite all the advances in microprocessor design the preferred chip for spacecraft is still one of the (80)486 line which is the most resistant to deterioration from cosmic rays - more or less equivalent to EMPs. At last I noticed the 486 was still in production (not necessarily in the USA) for this sole reason.

Rob

[Russell Vance]

Thanks Rob,
In a previous life I did things for the government and I remember well the Mig 25 gig and the tech report of the stripdown (I also recall the Soviets objected strongly to having their airplane sent back to them as a box of parts)........indeed, the miniature valves and other rudimentary but rugged electronics equipment was a lesson to all but largely unheeded as later high tech aircraft went on to suffer from the effects of stray emissions ( microwave towers and directed beam transmissions were high on the list of places to avoid for one of our particularly prolific Fighter aircraft). Moral of this story: we can put a man on the moon and shoot stuff half way around the world but we still can't make a quiet plastic pickguard for something that hasn't changed for 50 years...sigh. R.