These last couple of days, my shack has started to look like a radio repair shop.
On Saturday, I attended a hamfest in the Grand Rapids area, and on the way back, stopped in Greenville to pick up some gear that the family of a Silent Key graciously agreed to donate to my middle school project.
The hamfest, though on the small side, was a lot of fun. At one table, I picked up an air variable capacitor for $2. At another, a crystal for 7.050 MHz for $3. The variable cap is for my regen receiver. The crystal for the matching transmitter. These two babies are going to form the basis of my homebrew station.
The guy who sold me the crystal was fun to talk to. He was a real tinkerer, and we had fun chatting about the various projects we have worked on. While we were chatting, a guy with a MI QRP Club hat came up and joined the conversation. The second guy already had a box full of junk that he said was destined for new projects. Just chatting with those guys made the drive worthwhile.
My New/Old IC-735
I also acquired an Icom IC-735 for $275. There were actually two IC-735s there, and the two guys selling them were situated right next to one another. The first one was a very clean unit and had a $285 price tag on it. I have purchased stuff from the seller before, and I know him to be a very reputable guy. The only negative that I could see was that he did not have a microphone for the radio.
The second IC-735 did not have a price tag, but it did have a microphone, and it even had the little plastic door covering the slide controls. It was dirtier than the first unit, which did give me some pause. At 9:45, both units were still available, and I decided to ask the second seller how much he wanted for his. He said, “Make me an offer.” When I offered $275, he grumbled a bit, but sold it to me anyway. As a bonus, he pulled out the original manual from a pile on the table. With that, I was done for the day, and headed to Greenville.
It’s always sad visiting the families of Silent Keys. This is the third time I’ve done this in the last couple of years. Fortunately, the families have been generally upbeat, and what I try to do is to explain how we will use their donations to help more kids get into amateur radio.
This gentleman had a collection of older gear including:
- a 2m handheld,
- three 2m mobile radios,
- a couple of power supplies,
- an Icom IC-730 (the predecessor of the IC-735), and
- some miscellaneous odds and ends
KB6NU Plays Radio Tech
So, now my shack is full of this old equipment, and I’ve been sorting through it all. I first tackled the 2m radios. Oddly enough, the handheld actually turned on, but the battery charge was so low that it quickly died. A trip to Batteries Plus should get this radio back on the air.
The three mobile radios were a mixed bag. After crimping some terminals on the power cord for the Icom IC-28A, I tried turning it on, only to find out that while it turned on, it wouldn’t stay on. Apparently, the detent in the power switch must have failed. I have an e-mail in to Icom to see if a replacement switch is available.
Update 6-9-06: The switch is indeed still available, and it only costs $9.73, plus $4 shipping. From all reports, this is a nice little radio, so investing 14 bucks in it is worth it.
The second one I tried was a Kenwood TM-2530A. This radio turned on, and stayed on, but when I tried to access the repeater, I got nothing, even though I believe that I programmed the PL tone correctly. After doing some research on the Net, I discovered that this radio had an optional tone board. I haven’t cracked it open, but my guess is that it either does not have the TU-7 tone board or the one in it has failed. I did find a company that makes a drop-in replacement, but they’re asking $60 for it!
The third time was the charm. This unit, an ADI AR-146, worked perfectly. A bonus is that it uses the same power connector as the Kenwood. So, one out of three isn’t bad, and the other two units are easily repairable.
Uh Oh
Sunday evening, I finally got around to hooking up the new/old IC-735. After crimping some Power Pole terminals to the end of the power cord and plugging it in, I was relieved to find it light up, and then even more relieved when I heard the receiver come to life.
I was less than relieved, however, when I tried to transmit. After connecting a straight key to the rig, and keying down, the lights dimmed, and even the side tone sounded chirpy. Uh-oh. I hooked up the dummy load and got exactly the same results. Since it was getting late, I disconnected everything and set it aside. The next day, I put out a query on the IC-735 mailing list.
I got a couple of responses, but both asked more questions rather than give answers. This was completely appropriate. One of the questions, for example, asked if this happened on low power as well as high power. Since I hadn’t tried this, I hooked it all back up Tuesday night.
This time, the problem was obvious. As usual, the problem was the operator, namely me.
I have one of those fancy Astron VS-35M power supplies, which not only has current and voltage meters, but also current and voltage controls. Since lately I’ve only been using it to power my VHF/UHF radio, I set the current control down fairly low. When I connected the IC-735, it didn’t complain with just the receiver drawing current, but when I tried to transmit, I hit the current limit, and the voltage dropped. Hence, the lights dimming and transmitter chirping.
I didn’t notice this the other evening when I first hooked it up because the power supply is behind my laptop and the meters weren’t readily visible. Tuesday evening, I moved the laptop, so I could see what the meters were actually doing. When I saw what was happening, my problem was immediately obvious.
All I had to do was crank up the current limit pot, and now everything seems to be working just fine.I tuned to 7.042 MHz last night, called CQ, and got a response from WB2JUF to the very first call. We had a nice half-hour long QSO, and he said the rig sounded good. Needless to say, I now feel much better about my purchase.
The last radio to get some attention was the Icom IC-730. After making a couple more contacts with the IC-735, I hooked up the IC-730. This time, I hooked up the Heathkit keyer so I didn’t have to use the straight key.
Again, the first time I called CQ, I got a reply, this time from KO1K. I mentioned to him that this was my first QSO with an IC-730 that I’d just acquired over the weekend, and he replied that he was also using an IC-730! Now, what’s the chances of that happening??
I went on to work a couple of DX stations after that – XE3ARV on 30m and EA6UN on 40m. So, overall, I’d say that the rig is working.
There are a couple of things that need some attention, though. First, it looks like the preamp relay has died. When I press the preamp button, the radio goes silent. This is, apparently, a common problem with the radio.
Second, it doesn’t hear quite as well as the IC-735. So, my guess is that it just needs some tweaking. I think this is going to make a great radio for the school station.
Bob says
I also hav an IC 735 and a 730. I’ve had them for years and would never think of selling either one. I am more of a “sparks” operater so I just installed an Inrad 400 Hz filter in the 730 (the 735 has the Icom 500 Hz.); really worth wihile additions. The 730 also has the optional PBT filter…SWEET!! The 735 has the Icom keyer built in. The slide switch for the cw speed is kind of touchy…it goes like 8wpm, 10 wpm, 12 wmp, 60wpm!! It takes some gentle nudging to get it where you want it but no great shakes. My 730 receives every bit as well as the 735 as far as signal strength goes but the 730 with it’s seperate osc. for each band is has a noticably lower noise thresehold. I’m sure the PLL units have been greatly improved since the 735’s day. Didn’t want to bother you with my drivel but its nice to hear from someone else that knows great rigs when he runs into them. Bob
Clint Venable kg6ch says
Just dug out my IC730 after years in a box. I am thinking of getting back on the air. I will pretty much need to start from scratch. I am wondering if the 730 will still fire up and if not what it would cost to repair it. Was working fine when it went into the box. It has been stored inside. I have heard that the caps can go flat when old radios are stored.
Clint
Dan KB6NU says
Hi, Clint–
You never know for sure until you fire it up, but I don’t think the IC-730 that I acquired had been used much before I got my hands on it. It worked just fine when I turned it on, except for the items I mentioned above. I still haven’t dug into mine yet to fix the preamp relay and do the tweaking.
Anyway, go for it!
Hector MacKinnon says
I inherited an Icom 735 from my father when he passed away recently, it works well although it seems to have a drifting problem of some sort, i.e., intermittently as you tune up, the frequency goes down. I understand from searching around this problem is caused from plastic trim capacitors on the PLL board that have dried up. On contacting Icom repair for help it looks like over a $200 repair. I am an ex Forces radio technician and could probably do the repair myself with some assistance. If you can provide any help it would be greatly appreciated.
Regards and 73’s
Hector – VE3EDM
Dan KB6NU says
Hi, Hector–
If you haven’t already, you should join the IC-735 mailing list (http://groups.yahoo.com/group/IC-735/). This topic has been covered there several times, by guys who know a lot more about it than I do. Just search the message archive for “trimmer caps” and you’ll find out just about everything you need to know.
You can also download the service manual from the Net. It’s at http://www.costablancacomputers.net/manuals/IC-735service.pdf.
73, Dan KB6NU
steve. says
Hello i have picked up a icom 745 the radio is in great shape but it has a drifting problem after about 10 min can anyone help thanks Steve.