NC-190 RF coil slug stuck
 

NC-190 RF coil slug stuck.
After repdressing some bad wireing, replaceing a couple incorrect value
resistors, a 0b2 tube, removing some giant solder blobs, fixing shorts and
replaceing the 5K volume pot with the correct 50k pot, the thing is working
but not spectacularly. Trying to align it but one slug, T3, won"t turn. Any
suggestions?

JOHN D wrote:
NC-190 RF coil slug stuck.
After repdressing some bad wireing, replaceing a couple incorrect value
resistors, a 0b2 tube, removing some giant solder blobs, fixing shorts and
replaceing the 5K volume pot with the correct 50k pot, the thing is working
but not spectacularly. Trying to align it but one slug, T3, won"t turn. Any
suggestions?



Is it a ferrite slug, with an internal hex/square/triangle hole for the diddle
stick to fit into?

-Chuck

"Chuck Harris" wrote in message
...
JOHN D wrote:
NC-190 RF coil slug stuck.

Is it a ferrite slug, with an internal hex/square/triangle hole for the
diddle
stick to fit into?

-Chuck

It is a hex hole ferrite slug. The slug is not damaged yet but it has
rounded off my plastic tunung tool. I think the sleeve is plastic.Some fine
dust may have set up around the threads. The chassis was pretty dirty.
John

JOHN D wrote:

Is it a ferrite slug, with an internal hex/square/triangle hole for the

diddle

stick to fit into?

-Chuck


It is a hex hole ferrite slug. The slug is not damaged yet but it has
rounded off my plastic tunung tool. I think the sleeve is plastic.Some fine
dust may have set up around the threads. The chassis was pretty dirty.
John

Hi John,

9 times out of 10, when a slug freezes that tightly, it is split in half
along one of the points of the hex. The tool spreads the slug when you
apply torque. The more torque, the more it spreads, and the more it
spreads, the more it locks.

The crack is never visible to the naked eye, and is usually too far into
the hole to see with magnification.

One way that I have successfully removed cracked slugs is using a round
cocktail toothpick and a drop of yellow carpenter's glue. Put a drop of
glue on the end of the toothpick, and insert it into the core and let it
dry overnight. The next morning it should screw right out. Be careful
not to use too much glue. It wouldn't do to have the core glued into the
coil form.

Once you get the core out, pick the yellow glue off, and glue the halves
of the core back together with water thin crazy glue.

-Chuck

"Chuck Harris" wrote in message
...

Hi John,

9 times out of 10, when a slug freezes that tightly, it is split in half
along one of the points of the hex. The tool spreads the slug when you
apply torque. The more torque, the more it spreads, and the more it
spreads, the more it locks.

The crack is never visible to the naked eye, and is usually too far into
the hole to see with magnification.

One way that I have successfully removed cracked slugs is using a round
cocktail toothpick and a drop of yellow carpenter's glue. Put a drop of
glue on the end of the toothpick, and insert it into the core and let it
dry overnight. The next morning it should screw right out. Be careful
not to use too much glue. It wouldn't do to have the core glued into the
coil form.

Once you get the core out, pick the yellow glue off, and glue the halves
of the core back together with water thin crazy glue.

-Chuck

I don't know if that's it but it sure makes sence. It has not moved at all
but I have felt the sleeve give slightly so I'm afraid to put any more force
on it. Even on the other bands the reception is not great so alignment might
not be the whole problem. Broadcast band seems good but maybe it's just the
strong signals makeing it seem better.
John

I ended up removing 2 IF coils and drilling out and replacing the slugs.I
used super glue to immobilize some of the coil windings and stop the forms
from turning.
Thanks for the toothpick & glue idea. I'll try that next time.

"JOHN D" wrote in message
news:Gk1ve.834$xL1.355@trnddc08...

I ended up removing 2 IF coils and drilling out and replacing the slugs.I
used super glue to immobilize some of the coil windings and stop the forms
from turning.
Thanks for the toothpick & glue idea. I'll try that next time.



90% of the time this is caused by worn tuning tools.

Pete

Uncle Peter wrote:
"JOHN D" wrote in message
news:Gk1ve.834$xL1.355@trnddc08...

I ended up removing 2 IF coils and drilling out and replacing the slugs.I
used super glue to immobilize some of the coil windings and stop the forms
from turning.
Thanks for the toothpick & glue idea. I'll try that next time.




90% of the time this is caused by worn tuning tools.

Pete

I think it's about time to bring up the old "tuning wand" idea
again for the new guys. A tuning wand is a plastic rod with a
piece of ferrite on one end and a brass slug on the other. The
idea is to insert the wand into a coil and see if the output
increases or decreases. The brass end reduces the coil inductance
and the ferrite end increases same. If the circuit is tuned
correctly, inserting eaither end will cause the output to drop.
No sense trying to remove a broken slug if the circuit is tuned
Ok as it is.

73, Roger



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