Solving antenna connector problems on Icom handhelds: IC2/3/4AT, IC02/03/04AT 
series

The BEST replacement BNC connector that I have seen (and have used to repair the 
jacks on 3 different Icom handheld radios) is made by Amphenol for Tektronix.  The 
last one that I have left has "28JR200-1" stamped on it

They are not in any catalog I can find, and are not in the Amphenol salesmans 
literature. 
I was told (after the salesman called the factory) that they are not available 
to the public unless you want to buy a bag of 500 of them. While on a business 
trip to Portland, Oregon I've purchased them over the counter from the Tektronix 
Company Store (which is open to the public) and also from the local Tek scope 
repair shop. Just ask for a replacement BNC connector for a tube-type Tek scope 
plug-in.

These special connectors are very "tight" connectors - the center contact has 4 
gold fingers to grip the male connector center pin. Once you have it in place 
you will find that the antenna does not wobble around. They are not cheap - 
between $4 and $5 each (early 1990s prices) comes to mind - but the oldest one 
that I fixed is stil going strong after 3 years of daily use (swapping the 
rubber duck for the external mobile antenna and back twice a day). The hole in 
the metal chassis and the plastic case both have to be enlarged slightly- just 
chuck the proper drill bit into a tap handle and it works fine. The pc board 
will have to be relieved a little, I used a tiny carbide bit in a Dremel moto-
tool. When you install the new connector throw away 3/8" piece of solid wire 
that Icom uses to connect the PC board to the BNC center pin. Replace it with a 
short piece of braid. I used a short length of the narrowest solder-wick I could 
find, but another friend used a small piece of RG-174 braid. It is 'way too 
wide, but it worked. You're after a flex connection between the board and the 
connector pin. It's a little tricky to make a connection with the solder-wick 
without filling up the braid with solder, but it can be done. Yes, the whole job 
is tedious, and you'll be swearing at the original design engineers and making 
comments on their ancestry while you do it, but the couple of hours the job 
takes is worth it.

You'll need, besides common hand tools:

The new connector. 

Some white heat sink goop. Note that it (at least the good stuff) has Barium in 
it, and that is NOT good for your health. Get a set of surgeons gloves, perhaps 
from a paramedic and use them. There is no way that you will _not_ get some on 
your hands. And you'll want to put some back on the radio heat sink anyway - the 
three radios I've done this mod on have all been short on it (note that you want 
just enough to fill in the gap between the heat generator and the heat sink, and 
no more). And if there is not enough the final will overheat 'cuz the heat can't 
be carried away. The small tube I picked up at Radio Shlock 3 years ago is still 
1/3 full. 

A small piece of solder-wick type braid - the narrowest you can find.
Buy both a small roll of the narrowest and a small roll of the 1/4 or 3/8 inch 
wide stuff - you'll need the bigger stuff to clean up the PC board where the old 
center contact is soldered and wired down.

A small needle-point soldering iron - I use a Weller solder station with the 
narrowest 700-degree tip they make.

Thin solder. I have a roll of .015" that I bought specially for doing fine work. 
It goes fast, but in compensation there is a _lot_ on a roll.

A few drops of stiff Locktite or similar thread locking compound. I keep a small 
bottle of each of four different grades in my automotive tool chest.  Ak Miller 
introduced me to it as a way to prevent the ignition points on old car 
distributors from drifting and I've had some in the tool box ever since.

You will have to make your own thin wrench to get the nut on the connector off 
and the new one on. There is very little room in the radio to do this. I ended 
up ruining the hinge on a pair of cheap long-needle-nose pliers, then I had a 
light-bulb moment: I put the hex nut from the new connector in a vise and used a 
saw blade in the Dremel to cut a shallow groove in each flat, near the peak 
between two adjacent flats. I threaded the nut back on the connector (lock 
washer first), then used a screwdriver blade in the grooves to spin the nut. 
When the nut got tight I put a drop of Locktite on the threads, and before it 
dried I used a couple more taps with a light hammer on the screwdriver handle 
end to make it really, really snug.
An alternate method would be to use a drill bit and make a depression in the 
nut peaks and use an awl point in the depressions to turn the nut.
You may have a problem losening the old connector nut. On one radio I ended up 
using the carbide tip on the Dremel to cut through the old nut, then widening it 
with a twist of the screwdriver blade. Yes, I chewed up the threads on the old 
connector but so what? that connector was coming out anyway.

-- Mike Morris WA6ILQ