Solving antenna connector problems on Icom handhelds: IC2/3/4AT, IC02/03/04AT series... by Michael Morris WA6ILQ 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 part number stamped on it is "28JR200-1". 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 business trips 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/calibration shop near the TRW and Hughes plants in Los Angeles. Just ask for a replacement BNC connector for a Tek scope plug-in. I've fixed several plugins and handhelds, and I buy the connectors 5 or 6 at a time. These Tek BNC connectors are very "tight" connectors - the center contact has 4 springy 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 radio metal chassis and the plastic case both have to be enlarged slightly - just chuck the proper drill bit into a tap handle and that works fine. The pc board will have to be relieved a little for the center pin, I used a tiny carbide bit in a Dremel moto-tool. When you install the new connector throw away the piece of solid wire that Icom used to connect the PC board to the BNC center pin. Replace it with a short piece of narrow braid. I used a short length of the narrowest solder-wick I could find. 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, or you can wash the flux out of the braid with rubbing alcohol. Yes, the whole job is tedious, and you'll be swearing at the original design engineer 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. Get a set of surgeons gloves, perhaps from a nurse or paramedic and use them. There is no way that you will _not_ get some on your hands. And you'll want to add some back to 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. Solder-wick type braid - some 1/16 inch if you can find it, some 1/8th inch will do, and also some of the wide stuff - you'll need it to clean up the PC board where the old center contact was soldered. 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 blue Locktite or similar thread locking compound. Ak Miller introduced me to it as a way to prevent the ignition points on old car distributors (my first car was a 1957 Buick) 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 blue Locktite on the threads (NOT the red stuff), 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 Dremel and a tiny 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 / breaking 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