[AMRadio] Squeaky roller inductor

Geoff/W5OMR ars.w5omr at gmail.com
Sat Feb 3 08:52:15 EST 2007

A.R.S. - W5AMI wrote:
> I've got a rig that has a squeaky roller inductor in the tank circuit
> and would love to quiet it down, not to mention have it turn a bit
> smoother.  Does anyone have any ideas on some sort of HV lubricant
> that could be used in this part of the circuit without any sort of ill
> effects?  Without looking, I'm pretty sure there is no DC on the
> inductor, but surely a lot of RF voltage with an 3cx1500 final.
> I've been reluctant to try anything...

I worry, Brian, that any 'spray lubricant' will get on the ceramic coil 
form, and create a 'path' that will cause arcing.
I knew a guy a long time ago, that wanted the plate caps to make better 
contact on the (6) 6JB6 sweep tubes he was running in a (*ahem*) 10m 
(*ahem*) amplifier.
Sprayed 'em all with WD-40, and hit the switch. *POW*  *BANG*  *POP*  
*ZORCH*  followed by a string of expletive deletes,  the dog ran under 
the bed for cover, the wife ran from the house screaming and Jerry just 
sat there looking as if someone had run over his best hunting dog.

Couldn't have happened to a better Maco 750.

I wish I would have been there to prevent him from using some conductive 
spray lubricant onto a device that contains high voltage, be it AC or DC.

...for what it's worth...

If you can find some Graphite, you can apply it to the inside groove of 
the roller as it meets the inductor.  You can also apply a small dab on 
the arm that the roller travels on, as well as on the tabs that make 
contact with the rolling inductor on each end of the frame.  A little 
bit of that stuff goes a -long- way.

Liquid Graphite is basically the same stuff that pencil lead is made 
of.  Ever draw an arc from your final with a pencil? 
Some of you old timers know what I'm talking about.

Rest his soul, Koby/K5MZH (as I'm told by Otis/K5SWK) used to draw an 
arc with a pencil on his 833 final, and light his cigarettes with the 
flame of the arc.

By the way, for those of you who know Otis, we'll be gathering at the 
Golden Corral in Humble, TX (FM 1960 just West of Highway 59) this 
coming Wednesday, the 7th of February, for his 84th birthday.  Time is 
around 1pm.

See if you can locate some liquid graphite, Brian, and use sparingly.  A 
little of that stuff goes a long way.

73, etc...

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