[Amps] Roller inductor & wiper "grease""

Gary Smith Gary at doctorgary.net
Sun Nov 25 17:11:01 EST 2007


I just bought a transmatch and the capacitor was extremely loose but 
I figured I could repair it, it was loose enough that the weight of 
the rotor would cause gravity to spin it downward. 

I opened up the tuner and found what looked like black grease on all 
the friction points of the rotor. I disassembled it, found the 
friction clutch to govern the tension on the rotor and made all free 
of grease and now the capacitor works perfectly with good friction.

I saw a similar grease on the inductor at the same contact points. 
The seller said he hadn't worked on it and the capacitor seemed to 
hold for him and I took him at his word and I left the stuff not 
wanting to backward engineer the design of the thing.

Now I'm finding when tuning on 10 meters that with the tuner active, 
higher power causes the reflected power to jump all over the place 
but when running straight through & bypassing the transmatch there's 
no jumping of SWR at all.

I was thinking when I first saw the "grease" that it was there from 
the beginning but now I'm thinking it was added but a previous owner 
to make the mechanics works more smoothly without regard to RF issues 
that would bring.

Below is a photo of the inductor & wiper asembly. You can't miss the 
grease or whatever it is on the components. 

http://doctorgary.net/nye_inductor.jpg

I am thinking I wasn't told the whole story when I bought the 
transmatch. So here's some questions for the group;

Is the black grease you see here something that comes on some edge 
wound inductors?

If as I suspect it is something applied by someone before me, what 
would be an effective way to remove this grease? I hate to have to 
disassemble the whole thing but will if that's the only way.

I was thinking about putting rags in the bottom to keep it clean 
after spraying the greased parts with starting fluid which would 
surely degrease.

Not sure what if anything should be applied to the contact surfaces 
after all the grease is removed. Or does this greasy stuff actually 
belong there?

Thanks,

Gary
ka1j


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