[R-390] Tuning the IF Second Question Stuck Slugs

[Flowertime01 at wmconnect.com]

Paolo Gramigna asked

Now, to the second question: the IF lugs are sometimes stuck in place, and 
Iam afraid to breack them. What is the best de-stucker and lubricant for them?

_______________
Paolo,

This question comes up often. 


Watch the other mail and see what other advice you get.
Do not jump right into this problem.

Do you really need to get the skug unstuck?
How do you get the slug unsuck?
What do you lubricate the slug with once it free to keep it from deizing up 
again.

Then we throw in a whole bunch of stuff not to do.

Go through the alignement and just leave the stuck slugs alone. These 
receivers are over 50 years old and receivered lots of regular service in their day. 
No reason at all to belive the stuck slug is not set at almost its best 
position. Align the receiver and see what the signal to noise ratio is. Then try 
some tube swapping to get the ratio up a little better. 

If and only if the reciver will not get you better than 15:1 signal to noise 
ratio and you can isolte the loss down to the stage with the stuck slug, then 
worry about getting it to adjust.

Worry not if you break the slug. A broken slug can be replaced. A real 
concern is twisting the core inside the can and breaking a wire between the winding 
and the terminals inside the can. Pull the cover off the transformer so you 
can see your core and coil winding before twisting very much on the slug.

Never, never, never use WD40. The long term effects are more trouble than you 
want.

There is no magic solvent that we just "know it works".
Apply some rubbing achole and take the next day off while it all soaks in.

Good lights and a neddle may help you dislodge some gunk. large amounts of 
air may help blow some crud out of the tube and help free the slug.

Use a metal hex key in the slug to turn it. You may have to move the top slug 
a bit so the key will drop through the top and bottom slug to turn the bottom 
slug.

Heat the metal key with a solder iron to "melt or soffen" some of the gunk.

Hair dryers have been used to good effect for this. Gently warm the whole 
slug tube with the transformer cover off  and watch the resin melt. Let the heat 
soak through the tube a bit before trying to turn the slug.