Hey, folks. I just got back from the WWCC's April Maneuvering Event. Lots of fun, and lots of boats. Unfortunately, my primary transmitter is giving me trouble. It's an old Futaba FP-T7UAF digital radio. Top of the line, all of twelve years ago (or so I'm told). It's got a nifty little display that helps with programming mixes and setting stuff up. When I'm not programming it, the little display shows battery voltage and power draw. Well, this morning I noticed that the power draw was a little low. Normally, it shows around 100-120 mA of current. This time, it showed 3 mA. I thought "Hmm, that's funny." I then turned on my ship to check systems. The no-signal failsafe shut it down two seconds later. Not good. So here's what I've checked so far. All the computer brains seem to be working, as do the basic controls. It just doesn't seem to be transmitting. There are no wires broken loose inside that I can see. I also tried switching out the frequency module, and that didn't work. Does anyone here have some ideas? What's broken and what can I do to fix it?
My first guess is that the batteries may have died if they are old nicads. I had an old airtronics radio (heavily customized, not terrible modern) that had glitches. I changed to a regular alkaline battery pack, and bought lots of AA's when the Homier tool fair came by. It cleared the problem. I'd try verifying that the current supplied to the radio was on par if you haven't already. If it's the pack, battery replacement should be easy. Other than that, I think the magic smoke may have escaped. Mike 3
Yup, it may be the battery pack. Sounds like one or two of the cells in the pack may be gone. Have you tried swapping packs with another transmitter to see if that solves the problem? I have two of those transmitters and they are still one of my favorite aircraft transmitters to this day.
Well, I charged the battery overnight. The voltage is up to 11.3v and the current draw went up to 6mA, but still no signal. I switched out for a different battery pack, and again 6mA and no signal. I guess it really is dead I am now looking at replacement radios. It's rather annoying, none of the new radios look as cool as the old ones. All those rounded edges and black plastic just don't compare to shiny metal. Oh well, I gotta have a radio...
Other than looking around for a loose connection, scorch mark, or something else odd, I can't think of much. Maybe probe around with a voltmeter for voltage drops (5V is the reference/supply voltage used most places except the RF section on most radios, but I don't know details about yours). Without schematics (which are tough to come by) it might be up to sheer luck to find some toasted component, & even then it might be hard to find a suitable replacement. JM
If you happen to find out what the problem is, I have a parts transmitter I can pull a part from and send it to you.
