World Radio Labs - ICOM IC-27A Intermittent Transmit Repair

I have an old ICOM IC-27A which I picked up at the TARCfest a year ago. Naturally, the fellow I bought it from said it works perfect and of course I trusted this was true.

As luck would have it, it did work- if you call having no sound from the speaker working and a loose mike plug working. I replaced the speaker- luckily I had one from an old computer case small enough to fit inside the rig. I took the mike socket apart and cut but the cable end a couple inches as this is where the strain usually causes weak and broken wires in the cord. After resoldering I thought the rig was fine- a quick bench test indicated so. Once it was installed in my shack on wheels, I found that sometimes it works on tranmsit, sometimes not. I figured I have a bad plug or socket- the easier item to try first is the plug, so I ordered both items from R & L. The IC-27A has a 8 pin mike plug that is recessed so a regualr plug will fit, but not screw down. The guy at R & L was nice enough to remind me of that when they asked what I was putting the plug into.

When the plug and socket arrived, I set about to install the plug first. After careful soldering, I fired up the rig and same thing. intermittent transmit. I noticed if I pushed and held the plug to one side I could transmit. So I took the rig aprat to check the socket and replace if needed. That's when I got lucky!

The socket is soldered to a small PCB and it looked great. No cold joints on the board as I had hoped to see. Then I noticed the board has two ground leads, one a solid wire soldered direct to the chassis, the other black wire should go to a ground point somewhere- but it was never soldered. A close look at the joint on the solid wire, where it was soldered to the front panel chassis showed a broken joint- the reason it worked when pushed over. The other ground wire, had it been soldered, might have prevented this issue in the first place. I resoldered the chassis ground, found a ground point for the wire, reassembled the unit and now it really does work perfect!

This is yet another example of why you should NEVER use solid wire for grounds on mobile equipment- not even internal. After years of bumps and shocks, they WILL fail. ICOM engineers knew this and put two in place. It is easy to see how a lack of a redundant ground could be missed at the factory.

Here is a photo I took of the Icom 27A Repair

73- Bill N4BKT