[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 
 I am afraid to break 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.

The answer has three parts.

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

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

Go through the alignment and just leave the stuck slugs alone. These 
receivers are over 50 years old and received lots of regular service in their 
day. 
No reason at all to believe 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 receiver will not get you better than 15:1 signal to noise 
ratio and you can isolate 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 alcohol and take the next day off while it all soaks in.

Good lights and a needle 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 soften" 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.

Once you get the slug free what do you lubricate it with?

There is a magic white powder for this. If you are a radio guy you buy it in 
big packages from secret sources. Other wise you acquire a life time supply 
from a local shop that sells magic tricks.

The stuff is a power magicians rub on their card decks for magic acts. 
Someone will surely toss in a name for this substance here. 

Until you locate some "lube" just run the slugs out of the tube, clean them 
up as best you can and install them back into the tube.

Good luck with this

Roger AI4NI

P.S. I hate when I fat finger a function key and post half a mail.
Sorry Fellows.