So the questions a what happened to make them go bad, and can they
be reasonably repaired by the Bird Corporation? Although we will
be calling Bird personnel next week I thought I would throw out the
question here.


Do a Google search on the subject. You will find plenty of
information on this if you use the right search words. I suspect the
resistor or diode in the slugs are bad. Here is one ham's (now defunct)
website info I got off a Google cache:

Ed



Inside Those Bird Slugs

Did you ever end up with or do you now have a dead Bird slug? No, not
the kind you have in your shotgun but the kind which fits inside the Bird
Wattmeter series which makes them so valuable. Have you ever wondered
what was inside them? Well, I had one which I purchased at a hamfest
("Is it working OK?" "Sure, it is. I used it right before I headed
down here to the hamfest.") I foolishly believed the seller but once I
tested it at home, I realized that I had a dead slug. I have since found
a way to test them before paying the money and I'll be glad to share that
info later.

In addition, I was always curious as to what was on the insides of those
little beasts. After all, what could be inside to make that little
thing worth so much money? Since mine was dead, and I had little to
lose, I opened it up to see. I will share with you the inside story, and
I now know why they are so dear to the pocketbook.

I did not take this project lightly. I spent long hours searching the
Internet but was never able to find any information on the slugs
themselves, either pictures or text, to describe what the folks in
Cleveland placed inside those little gold cylinders. I hope this article
can save someone else some search time if they attempt the same endeavor.

First, to test a Bird slug (assuming that you are going to a hamfest),
take along a small VOM that has, at least, a resistance scale. If the
seller (assuming you are also buying at a hamfest) will allow you to test
it, place the VOM on a higher resistance scale (I used the 20K scale on
the little yellow $9 marvel I had). Hold the slug in one hand and place
one probe on the round shell of the slug while carefully touching one of
the small connection which is exposed on one side. Then reverse the VOM
leads. Test it just like you would test a diode -- you want continuity
in one direction and an open connection the other way. Then test the
connection on the other side of the slug the same way, expecting the same
results. If you find continuity, or a very low resistance, from the
shell to a connection in both directions, something is shorted in the
slug. If you find no continuity in either direction, something is open
in the slug. Either way will cause it not to work. On the one I had, I
had no continuity.

Over a period of months I would pick that slug up and try to twist, poke,
pull and generally try to see how to get inside it to see if anything was
obviously gone. It resisted my every attempt. My wife would have said,
"throw it away... it isn't any good. Just forget the money that you
wasted on it..........It's gone!"

I don't think so. 'Course I really didn't tell her that I bought a dud
so she didn't actually say that. Finally, over a year past the original
purchase, I decided to take drastic steps. After all, it's dead anyway
---- what can I hurt?

Carefully examining the dead slug revealed that someone had used some
type of grinding tool on the face of the slug on two sides. (I know, I
know, I should have seen that sooner......and especially before I bought
it.....) The two round grinding spots were within the arrow which seems
to be on all Bird slugs showing which direction it is to be turned.
One was directly within the arrow head and the other at the opposite,
tail side of the arrow.

With my Dremel tool and several different bits and stones, I was able to
grind down past the aluminum disk which is the label, and pop the label
disk off. I regret that when this activity took place, I did not own a
digital camera so I have no actual pictures of the following steps. Even
though I now have a camera, I cannot bring myself to re-enter the slug,
just to get pictures. I will attempt to be, in words, as descriptive as
a camera would have been in pictures.

Once the label disk was off, it revealed a cavity in the center with a
single screw which was covered with a sealer to show whether it had been
"messed with." Again, nothing to lose so I unscrewed that screw which
released the larger circular part of the slug. This is the widest part
of the slug which has the grooves and is gripped to rotate the slug in
the wattmeter housing.

Once the finger piece was off, I could see a 1/2 watt resistor with a
piece of spaghetti over one lead. It was soldered on one side to a
small terminal which was one of the two connection pieces which are
always visible on the side. The other lead of the resistor connected to
another terminal and on to the top of a diode coming through the
remaining part of the slug.

Two more screws were also revealed and once they were removed, the white
nylon cover which shielded the primary RF detection pieces was removable.
This round white piece of nylon is the piece which you see on the lower
section of all Bird slugs. The slug I had was a 50C which was calibrated
for 50 watts in the range of 100-250 MHz.

The RF detection parts were a 1 1/2 turn coil of about #18 silver plated
wire connected to the diode on one end and a flat feed-thru capacitor on
the other. The white nylon cover was actually a machined-out piece with
room to go around the coil and feed-thru. I had originally thought it
to be just an inverted bowl-type cover but it is much more rugged than
that.

I did not bother the coil or other parts inside the slug once I realized
that my problem was an open resistor. This resistor was marked 14K 1%
and had, no doubt, gotten too hot from excessive power so it opened up.
As Fortune had smiled upon me, I had an exact replacement resistor which
helped to speed the repair. I carefully bent the leads on the
replacement resistor to look exactly like the one it was replacing. The
defective resistor was easily and quickly removed and the replacement fit
back perfectly. I tried to use the least amount of heat on the
connections so as not to risk changing the value of the resistor.

Putting things back together, everything fit fine and there were no left-
over pieces (unlike some of my previous projects). The slug was tried
and worked as it was supposed to. At least, it read upscale when power
was applied through the wattmeter connectors.

Bird slugs are expensive because they are manufactured to close
tolerances and I imagine it takes quite a bit of time (Time = $$$$) to
assure the accuracy to which users have come to expect of Bird products.
My repaired slug certainly did read something but there was no assurance
that it would anywhere near the accuracy that was demanded of that unit.
I compared the repaired slug to another I had which covered the same
range and they read to same values. Yes, since that one had been
defective and I still needed that value, I had purchased another. The
repaired slug read the same as the untouched, other one which had become
its replacement. Lucky? Probably. Happy? Absolutely!!

Had I been able to verify the contents and inner make-up of the Bird slug
earlier, that is, if I could have read what you just read, I would have
started the repairs much sooner. It may be that I was just lucky and
attempting this project again on a different dud slug would have resulted
in a much different outcome. I was, however, very pleased with the final
result on this particular attempt. If you attempt the same, I hope you
have similar success because, as we all know, "A Bird in the hand
is............ oh, never mind....." ----- K5LAD