Static on some older prints?

[Robert Aragon]

I'll start with this..HELP!

I've just picked up a couple older prints and realize that there seems to be a static crackling sound on the main track.
Runs through the entire film and on each reel.
It doesn't happen on some other prints I have.
Any idea?
I'm lost and not sure what initially caused it or at best, how to eliminate it.
DRIVES me nuts.
I'll finish this with..HELP!
THANKS in advance.
ANY one else experiencing this?

[Steve Klare]

Hi Robert,

It's possible your prints have been exposed to some pulsating magnetic field and those bursts have wound up superimposed on your magnetic tracks. If that's the case you can't unscramble eggs and the only solution is to re-record.

There is another, much nicer possibility.

How's the weather where you are? By me it's been pretty consistently below freezing for a couple of weeks. The humidity in the air is very low and it's easier for static electricity to really get going.

At times like this, your carpeting and your doorknobs conspire against you!

Now you take this multiple-hundred foot long strip of insulating material and drag it though this machine with all sorts of insulating surfaces for it to rub against and then you pile it all up on a reel: let all that staticky goodness accumulate. In a way you've made yourself a really poor van de graaff generator: not like the really cool ones that make people's hair stand up in Physics class, but just enough to let out a static electric arc when the voltage rises up enough that the air can't hold it off anymore. With this you have a brief, intense release of electric and magnetic energy at the same time you have a magnetic head in attendance to make sound out of it.

It's natural to ask why just some prints do this when some don't and my honest answer is "I don't know!" -but I have one particular print that does this, especially in winter time. Maybe it's some coating it has that the others lack, or maybe vise-versa. I don't know, but there is something.

If I remember right, it's worse with a metal take-up reel. It seems to me that with a plastic reel the problem at least became less. Maybe a metal reel provides a discharge path and lets more of the charge jump off at once.

It's possible that in a few weeks when the outside world rises above freezing and the snows become rain, your crackling audio will quiet down all on its own.

In the meantime? Change things up: different machines, different reels, maybe film-guard one and see if that helps.

One thing you can do to figure out if it's in the track or just static is is play the same print several times and record it with a camcorder or cellphone. Something in the track will repeat perfectly between plays, but static will occur randomly and when you compare recordings, you will hear differences in the audio.

(Best of Luck!)

[Rob Young]

As Steve says, assuming it’s not on the recording, I’d go for a clean with Filmguard.

Years back I used to get static when playing back on my Elmo ST1200HD. Turns out I wasn’t the only one and the brass capstan was the cause, building up static. The fix was to attached a thin bit of flexible wire to the projector body and rest it gently on the flywheel in the back of the machine, acting to discharge the static. Never something I was happy with. Later, it had some work done and fitted with the modified capstan with rubber coating. Static vanished.

[Steve Klare]

-and ST1200HD is the machine where I've noticed it the worst, too!

[Paul Adsett]

The Elmo GS1200 has a sprung copper strap which rides on the end of the sound capstan shaft, and is grounded to the main circuit board.

[Rob Young]

Yes, Elmo definitely became aware of this issue on the ST1200. Mine is a later ST1200HD and the modified part was fitted around 1989 by Hanimex UK who were the Elmo suppliers and repairers at that time. It actually went in for other things and came back with the rubber coated capstan instead of the bare brass one. Static was gone after that.

[Paul Adsett]

I would think that the rubber coated capstan would also be beneficial in reducing slippage of the film on the capstan which would also reduce WOW. It doesn't seem that the rubber coated capstan ever migrated to the GS1200, where it could have proved beneficial for wow reduction as well.

[Brian Fretwell]

On rewinding an old print I hadn't lubricated I often felt a static shock when my hand touched the earthed metal arm of the projector. Static builds up when you run plastic (polyester in this case0) through material.

I also managed to crash a mainframe computer with "crowbar" protection in its power supplies (to detect earth voltage spikes if lightning hit nearby) by bumping a trolley of 10.5 in data tapes that had had their plastic cases polished into it when I turned a corner badly. the trolley had rubber wheels!!

[Mike Newell]

As Paul, said you could applying Film Clean to the film to see if that helps. Is the sound fault evident on other projectors? The other option is to use a head demagnetiser on sound heads of projector. Example attached. It might help.

https://www.juno.co.uk/products/tona...eel/567759-01/

[Robert Aragon]

THANKS so MUCH for the info..
I've ordered a Demagnetiser from The Reel image. Once it arrives, I'm sure I'll be posting something titled..
"How do I demagnetize the heads of my gs1200"?
Until then, I'm gonna try the filmguard solution as well.
Only happens with a couple of films and always in the same spot.
THANKS for all the info..
Blessings and thanks again

[Mike Newell]

Not an Elmo projector but same principle. Move slowly back and forward without touching heads

https://www.youtube.com/watch?v=FmaGpR_2oQQ