[dconant]

Hello,

Working on a 38-10 where the tuning cap gears have separated. I have got one spring out that was jamming the ability to rotate the shaft but can't get at the other one. I have removed the tuning shaft in order to free it up since the center does nothing. Probably hardened grease. Any ideas on how to get the rest of it apart so I can get the one gear back in place and both springs back.

Thanks,
Dan

[Vlad95]

It is possible (but not always, depends on the design of the capacitor), but it is a very precise job.
It is necessary:
1) set to the minimum capacity position (fully extend the rotor from the stator)
2) completely unscrew the rear centering screw
3) remove all the balls from the front bearing
4) tilt the rotor and remove the axle from the front plate.
5) assemble in reverse order, generously lubricating the balls and other rubbing surfaces with Vaseline before reinstallation.
6) adjust the position of the rotor with the rear screw, checking for short circuit of both sections in any position.

[dconant]

Thanks for the reply Vlad95. I can't even see the balls let along try to remove them. The grounding forks are going to prevent removing the shaft. I guess I will just see if I can remove the other spring somehow and get things back in place.

[dconant]

I managed to get the gears lined up and the springs back in. Much easier than it thought. Putting a thin wire down inside the spring helped and kept the spring from launching into never find it again land.

[RodB]

Vlad, your comment about Vaseline brought a thought. Does anyone know the long term affect on using silicon grease on those capacitor bearings? I've wondered what the longevity is.

[Vlad95]

RodB
I have been using pure Vaseline for a long time for thick lubrication of home radio devices. The main reason is that it is the most oxidation-resistant lubricant (I don't know about silicone, maybe it is better, but it is certainly less common and accessible). Only the guaranteed service life when lubricated in open places is more than 10 years. Given that in similar conditions for greases like lithium it is only 1-3 years. In addition, it has no oil smell, does not get dirty. Other disadvantages such as low moisture resistance and temperature range are insignificant for our application. I also use it for lubricating bearings. In this case, its low heat resistance plays a positive role. At rest, the lubricant thickens and does not flow out, while it heats up during operation and becomes, as necessary, liquid.
I also use Vaseline to lubricate worn potentiometer surfaces to eliminate clicking noise.
Another positive point - Vaseline is neytral for almost plastics. Oil based grase can dissolved polistirole based plastic and broken its surface.