"Ed G." wrote:

Givem hell, Dean!

On the coils, I've found that heating the coil form (heat gun is best
but solder iron if done carefully ) will sometimes melt the wax on the
coil form allowing the slug to turn.

If not available, I have on occasion drilled a hole in the PC board
bottom of the coil; sometimes getting access for the tool through the
other end of the coil will make the difference.

If you do crack the coil, I assume you know its pretty much worthless
for reliability and proper tuning after that. Worse case, try to dig up
some used coils from other gear and just drill out the old core and
install a new one.

Good luck

Ed WB6SAT

I have put an old Allen wrench into a stuck slug and heated it with a
large soldering iron, then carefully remove the slug by turning the
Allen wrench with a pair of pliers while the slug was warm enough to
melt the wax.

One other thing, some coils are sealed with "Printer's Ink", a water
based ink that chips easily. We used it on all the coils in the PRC-77
radios built by CE.

You have to be careful drilling holes in circuit boards. I have
worked on a lot of RF boards with traces run under coils that will be
destroyed with a drill bit.
--


Michael A. Terrell
Central Florida

I have put an old Allen wrench into a stuck slug and heated it
with a
large soldering iron, then carefully remove the slug by turning the
Allen wrench with a pair of pliers while the slug was warm enough to
melt the wax.


That's a good way of transferring the heat. But care must be taken
not to tork the allen wrench too much. I've broken far too many slugs
with those inflexible steel tools.


One other thing, some coils are sealed with "Printer's Ink", a
water
based ink that chips easily. We used it on all the coils in the
PRC-77 radios built by CE.

Thanks for that reminder. Forgot about some water soluble sealers.


You have to be careful drilling holes in circuit boards. I have
worked on a lot of RF boards with traces run under coils that will be
destroyed with a drill bit.

That's a given, that care must be taken where you drill. I've never
damaged a trace yet, though I've opted not to drill some. Of course if
the board has internal traces (sandwich) forget it!!


Ed

"Ed G." wrote:

I have put an old Allen wrench into a stuck slug and heated it
with a
large soldering iron, then carefully remove the slug by turning the
Allen wrench with a pair of pliers while the slug was warm enough to
melt the wax.


That's a good way of transferring the heat. But care must be taken
not to tork the allen wrench too much. I've broken far too many slugs
with those inflexible steel tools.

One other thing, some coils are sealed with "Printer's Ink", a
water
based ink that chips easily. We used it on all the coils in the
PRC-77 radios built by CE.

Thanks for that reminder. Forgot about some water soluble sealers.


You have to be careful drilling holes in circuit boards. I have
worked on a lot of RF boards with traces run under coils that will be
destroyed with a drill bit.

That's a given, that care must be taken where you drill. I've never
damaged a trace yet, though I've opted not to drill some. Of course if
the board has internal traces (sandwich) forget it!!

Ed

The last boards I worked on were 16 layer. About the only place you
could drill was through a bad via the connected the top and bottom
layers. At up to $8000 per board, they were rather fussy about extra
holes in new boards.
--


Michael A. Terrell
Central Florida

that was semi-official repair policy for apple II computers in the
minnesota education system... turn it off, lift it up a foot or two, and
flat-foot slam it back on the table. oxidation and heat popping on the
tin-socketed chips, you understand, and the machine was well enough
built so you could get away with it.

Jim Hampton wrote:

Dean,

This is one reason we have problems attracting newcomers. The incessant
flames. The fact is once you mention "tubes", folks should realize that the
thing may indeed not be well tuned. I'm trying to think if it is the GE
Master II ... but it is a VHF rig and the cavities used to grow "crystals"
in 'em and detune 'em. One guy showed me a quick way to fix it (yes, you
can go in with a q-tip). He picked the radio up and banged it on the bench
about 3 or 4 times. Suddenly, it no longer took 4 uV to get a decent
signal. It was down to 0.25 uV. I did have to clean my shorts out the
first time I saw it, however

I was given an old SP-600 which had been under salt water for a brief period
of time (I got the radio in 1968). I ended up replacing most of the
components in the whole front end as it could barely receive local broadcast
stations. It worked fine after I did that, but it was a real mess. Easier
to buy a new receiver these days (prices are reasonable and if you figure my
time, I was probably making about twenty five cents per hour fixing that
slug!). Of course, that was back in the late 60s. Figure a grand buck and
a half an hour in today's wages It was a good learning experience,
however.

73 from Rochester, NY
Jim

"

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-- If it's a "new economy," why do they want my obsolete old money?

that was semi-official repair policy for apple II computers in the
minnesota education system... turn it off, lift it up a foot or two, and
flat-foot slam it back on the table.

Actually, there's a number of old repair techniques like this that don't look
very professional, (Especially if the customer sees you do it.) but work very
well. For example:

A buzzing transformer lamination can often be cured by whacking the corner of
the laminations with a hammer.

On old Hammond organs, noise in the vibrato can be cured by pulling the
rectifier tube, connecting a clip lead to pin 8, reinserting the tube, turning
the organ back on, then touching the other end of the lead to the center pin on
the vibrato scanner for a few seconds. "Whiskers" in the scanner will be blown
to smithereens and cause no problems for years.

K5DH wrote:

I am restoring an old Kris 23+ tube-type CB radio.
As with most Japanese-made CB gear from that era,
the coil slugs are held in place with some sort of
glossy white paint-like sealer. How do I dissolve
that sealer without damaging the coil forms? I'm
unable to budge the slugs with a diddle stick, and
I don't want to risk fracturing a slug by trying
to force them.

73,
Dean K5DH


I've always had good luck by heating the slug with a soldering iron tip,
set on low heat. The "gliptall" will usually melt before the coil form
does, but be careful just the same.

Dave
"Sandbagger"

(K5DH) wrote in message ...
I am restoring an old Kris 23+ tube-type CB radio.
As with most Japanese-made CB gear from that era,
the coil slugs are held in place with some sort of
glossy white paint-like sealer. How do I dissolve
that sealer without damaging the coil forms? I'm
unable to budge the slugs with a diddle stick, and
I don't want to risk fracturing a slug by trying
to force them.

73,
Dean K5DH

Gday Dean,
dont get too upset about the "screwdriver expert" jibe - we have to
rely on the printed word in front of us and take that at face value.
Its been a good subject, thank you for kicking it off, and there has
been lots of useful ideas to try, so just accept that. If we were face
to face or on air, it wouldnt be a problem but using this particular
medium misunderstandings and errors do occur.

And I am sure you will agree that as a working tech you MUST have seen
the results of inexpert slug twiddling - sort of like old British
motorbikes whose ten previous owners only had a 12" shifting spanner
as their major (or only) tool....

73 de VK3BFA Andrew

Scott Schrader wrote in news:3F4E39DD.A59629F7
@visi.com:

try alcohol first for solvent, it should not mangle coil forms. if that
doesn't work, a paintbrush with a little bit of acetone is the next step
for solvent.


What I did for those stubborn slugs was to heat them with the tip of my
weller. The heat will soften the paint/sealant and not damage the coil
form.

r

Irv Finkleman wrote:

K5DH wrote:

I am restoring an old Kris 23+ tube-type CB radio.
As with most Japanese-made CB gear from that era,
the coil slugs are held in place with some sort of
glossy white paint-like sealer. How do I dissolve
that sealer without damaging the coil forms? I'm
unable to budge the slugs with a diddle stick, and
I don't want to risk fracturing a slug by trying
to force them.

73,
Dean K5DH

Usually a drop of solvent will loosen them. If the coil
forms are plastic it might be a problem, but you can test the
solvent on the end of the form first.
--
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-- If it's a "new economy," why do they want my obsolete old money?



--
"Any sufficiently advanced technology is indistinguishable from
magic."

Arthur C. Clarke (1917 - ), "Technology and the Future"

On Fri, 29 Aug 2003 13:00:12 -0500, Scott Schrader
wrote:

that was semi-official repair policy for apple II computers in the
minnesota education system... turn it off, lift it up a foot or two, and
flat-foot slam it back on the table. oxidation and heat popping on the
tin-socketed chips, you understand, and the machine was well enough
built so you could get away with it.

But the skill is in where and how hard to hit it ;-)

Worked with a piece of production equipment I dealt with, with a relay
which stuck occasionally, no matter how many times it was replaced
(Note: never buy serial # 0001 of anything).

It was far simpler to kick it in just the right spot.

Happy trails,
Gary (net.yogi.bear)
------------------------------------------------
at the 51st percentile of ursine intelligence

Gary D. Schwartz, Needham, MA, USA
Please reply to: garyDOTschwartzATpoboxDOTcom