[R-390] Help getting unstuck!

[Craig C. Heaton]

Hello to All,

The worst of the caps were the Brown Beauties! Using a Sprague TO-6A,
couldn't get any of these to provide a reading as to value. As far as
insulation resistance, most were close to nil. Some of these had something
that looked like dried brown snot on them. Good stuff to auction as Rare
vintage Collins equipment on that E place.

The Vitamin Qs were for the most part fine business, good values and IR.
Since I had them out for inspection, it was easy to replace these while the
iron was still hot.

C603, all three 30uF sections read about 60uF and somewhat leaky. C606, both
47uF sections read about 75uF and leaky. Not bad for 1956 vintage, they
served their country well. C103, a Pyramid from 1957 was a dead short.
Stuffed that can with a new 50uF 50Vdc electrolitic cap. Last, C551 that oil
bath 2uF can, it read 2.25uF and no IR. I cut that bad boy open with a
dremel tool and put a NTE-MLR205K630 (Mylar 2uF) inside. Never tested an oil
paper cap before, maybe didn't need to replace C551, but didn't like the
zero insulation resistance.

Was this Motorola a Saint Julians Creek special? I don't know, its a Order
NO 14-PM-56-A1-51, if that adds to the conversation. All the sub-chassis
have the same Order NO and are Motorola.

I've been trying a little WD-40 applied with a tooth-pick and a hair drier
to free the slug. Gots lots of time to free that pesky critter up. Could
leave it alone and do the best I can with the others. But I do like the idea
of a root canal. Need some spare parts before surgery!! Either a good T501
or a slug will do the trick.

Tnx,
   Craig

-----Original Message-----
From: Cecil Acuff [mailto:chacuff at cableone.net]
Sent: Friday, April 01, 2005 2:38 PM
To: Craig C. Heaton; R-390A
Subject: Re: [R-390] Help getting unstuck!


Craig I don't have any magic answers on the stuck slug but I am curious
about the caps.  Black Beauties?  Brown Beauties?  Split, leaky or out of
spec in some way?  Was it a Saint Julians Creek special?

Others experiences are important info in this area.

Common wisdom ranges from "Leave em alone it's not necessary" to "Change em
all their evil"....and even "Only change em if they came from the SJC".
(not so common a wisdom I guess)

You might try removing the can cover on the stuck slug and gently heating
the form with a blow dryer or the slug with the tip of a soldering iron then
trying to break it loose.  In another product with the same problem I have
actually drilled out the center of the slug progressively....like a root
canal and eventually reduced it to pieces to fully remove it and replaced it
with a similar slug....I wouldn't think it would be too critical.

My couple pennies worth.

Cecil...
----- Original Message -----
From: "Craig C. Heaton" <wd8kdg at worldnet.att.net>
To: "R-390A" <r-390 at mailman.qth.net>
Sent: Friday, April 01, 2005 12:35 PM
Subject: [R-390] Help getting unstuck!


> Good Morning to All,
>
> Just finished putting a Motorola R-390A back together. Had to replace many
> evil out-of-spec and leaky capacitors. The good news is no magic smoke
> escaped while plugging the receiver into a source of electrons. Thought it
> might be a good idea to realign the receiver, it was receiving slightly
> before my attempts at restoration.
>
> Now the sticky question. Can't seem to get the top slug in T501 to move.
> All
> of the other slugs will move. This transformer has a cover with a hole
> punched in the top center. Looks like a little rust between the slug and
> coil form. I doubt I'm to first to tackle this sort of challenge. Anyone
> been here before? What sort of fixes for a stuck tuning slug? Of course,
> if
> it never moves again or I break it, does anyone have a spare?
>
> Seem to remember hearing in the Navy, "If its tight, its right". This one
> is
> real tight, need to make it wrong.
>
> Tnx,
>    Craig
>
> _____________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/faq.htm
> Post: mailto:R-390 at mailman.qth.net
> Unsubscribe: http://mailman.qth.net/mailman/options/r-390
>