It's a good thing that troubleshooting systems failures has been a big part of my career - the training for owning airplanes is priceless! take, for instance, the following tale of electronic woe.....
Several weeks ago, Louise started noting that she was having problems with her Number 1 Comm, an SL-30. She couldn’t put her finger on it, but she seemed to be missing calls, and occasionally, others couldn’t hear her. The problem seemed to be intermittent, and she got mixed results when she did voice checks with the Tower folks at the other end of her daily commute. We couldn’t be absolutely sure that it wasn’t an audio system problem, as there were times that the Number 2 Comm (an A-200) seemed to join in the fun…puzzling.
It finally reached the point where we had to do some systematic troubleshooting, the intermittent nature having settled down to “every flight” and becoming more than just an annoyance. The first and easiest thing to do was swap headsets, so we pulled out a practically-new ANR Lightspeed we keep for passengers, and tried that. The problem persisted. Next, I thought that maybe it was the headset jacks that had gotten “tweaked”, and weren’t making good contact, so I dove under the panel and gave them a nice squeeze. More flying with the two of us – good intercom, problems with Number 1 Comm. We could bring in AWOS’s at the start of a flight, but as the flight progressed, they became less and less reliable, until finally, we couldn’t hear a nearby (5 miles) station. Hmmm….range dependent, and worse with time. Antenna issues? Heat related problems?
We did some two-ship local flying, separating in different directions to put some distance between us, and sure enough, the SL-30 just seemed to die slowly, and become useless after ten minutes. Since we have interchangeable audio panels, I figured it would be quick and easy to rule out that part of the fault tree, so we swapped an launched again. The problem….persisted! (And it didn’t swap airplanes, so we knew her audio panel was good. It was not looking good for the radio….)
I put out a call for anyone close by that might have an SL-30 we could borrow. Sure enough, a local RVater was down for an engine overhaul. He had his panel out and at home, and was gracious enough to let us borrow his unit for a day. We made a short evening flight, and wow – did it sound great! After ten minutes, it still sounded good, so I told Louise I was headed home, and landed – and didn’t hear from her again until she taxied up to the hangar. The problem had…persisted! (I had turned back too early….)
OK, so it’s not the radio – could it be the antenna? Heat/time problem with an antenna? Well, it wasn’t hard to test – I crawled back under the panel (by now, I have a system – it involves big pillows…), and swapped the antennas between the two Comm radios. Too late to go flying, we hooked the airplane up to external power and let the radios warm up – then I took a walk with our handheld. Sure enough – the problem persisted! I couldn’t get more than 200 feet away before she couldn’t hear me on the SL-30. And the mosquitoes were in attack mode. I was not happy.
So it’s not the radios, the antennas, the audio panel, headsets, audio wiring…the only thing left was the audio connections between the SL-30 rack and the audio panel rack, plus the short little pigtail antenna connectors on the SL-30 rack.
Now, we had built this panel from scratch about a year and a half ago, and it had worked just fine until this recent problem. Most of the panel was new, but the SL-30 was a carryover from the old panel, Louise having bought it about three years ago with a pre-wired harness. The rack came with the Garmin right-angle BNC connectors prewired with 12” Coax pigtails terminated in Male BNC connectors. For those not familiar with the radio, it has two identical antenna connections, one for Comm and one for NAV, on opposite corners of the rack. The connectors are proprietary little buggers from Garmin with little mounting ears to screw them to the rack. They are the kind where you have to put the coax through from the side, and add one tiny drop of solder to join the center conductor of the connector to the center conductor of the Coax. Very ticklish little things. and impossible to find, except in an install kit from the “Big G”.
This evening, when Louise flew home from work, I pulled out my tools and dove once again under the panel. I was a man on a mission, with my headlamp lighting the way and tools in my mouth, It didn’t take too long to get the pigtail liberated from the rack, and over to the workbench. I unscrewed the cap, and began a forensic investigation.
As I unscrewed the nut that holds the outside braid to the connector body, I saw a curious thing – the center conductor was turning with the jacket – it wasn’t fixed to the blob of solder on the center post! Rather, it was turning WITHIN the blob of solder! It was not firmly attached – captured, but free to move. Given the incredibly hot temperatures we have been seeing, and the odd nature of RF problems, I became excited – I may not have found THE problem, but I sure found A problem! Out came the soldering iron, and I rebuilt the joint to specifications – nice and tight, with no movement, and no shorts (as checked by the DVM). Crawled back in the plane, invigorated by the fact that I’d actually found something, and had everything back together in 20 minutes. Ready for a test flight….which had to wait until the next day, as it was late, and I had "real" work to do...(which didn't pan out, unfortunately - hydrogen leaks are BAD!).
The next evening, Louise and I took off in both planes in quick succession for some in-flight testing, heading away from each other to check the range. Fifteen minutes later, we knew we had a winner - the radio was loud and clear, with no fading! I sure am glad that worked, 'cause if it hadn't, my next step was going to be to call an exorcist.....patience my eye....
Paul
Several weeks ago, Louise started noting that she was having problems with her Number 1 Comm, an SL-30. She couldn’t put her finger on it, but she seemed to be missing calls, and occasionally, others couldn’t hear her. The problem seemed to be intermittent, and she got mixed results when she did voice checks with the Tower folks at the other end of her daily commute. We couldn’t be absolutely sure that it wasn’t an audio system problem, as there were times that the Number 2 Comm (an A-200) seemed to join in the fun…puzzling.
It finally reached the point where we had to do some systematic troubleshooting, the intermittent nature having settled down to “every flight” and becoming more than just an annoyance. The first and easiest thing to do was swap headsets, so we pulled out a practically-new ANR Lightspeed we keep for passengers, and tried that. The problem persisted. Next, I thought that maybe it was the headset jacks that had gotten “tweaked”, and weren’t making good contact, so I dove under the panel and gave them a nice squeeze. More flying with the two of us – good intercom, problems with Number 1 Comm. We could bring in AWOS’s at the start of a flight, but as the flight progressed, they became less and less reliable, until finally, we couldn’t hear a nearby (5 miles) station. Hmmm….range dependent, and worse with time. Antenna issues? Heat related problems?
We did some two-ship local flying, separating in different directions to put some distance between us, and sure enough, the SL-30 just seemed to die slowly, and become useless after ten minutes. Since we have interchangeable audio panels, I figured it would be quick and easy to rule out that part of the fault tree, so we swapped an launched again. The problem….persisted! (And it didn’t swap airplanes, so we knew her audio panel was good. It was not looking good for the radio….)
I put out a call for anyone close by that might have an SL-30 we could borrow. Sure enough, a local RVater was down for an engine overhaul. He had his panel out and at home, and was gracious enough to let us borrow his unit for a day. We made a short evening flight, and wow – did it sound great! After ten minutes, it still sounded good, so I told Louise I was headed home, and landed – and didn’t hear from her again until she taxied up to the hangar. The problem had…persisted! (I had turned back too early….)
OK, so it’s not the radio – could it be the antenna? Heat/time problem with an antenna? Well, it wasn’t hard to test – I crawled back under the panel (by now, I have a system – it involves big pillows…), and swapped the antennas between the two Comm radios. Too late to go flying, we hooked the airplane up to external power and let the radios warm up – then I took a walk with our handheld. Sure enough – the problem persisted! I couldn’t get more than 200 feet away before she couldn’t hear me on the SL-30. And the mosquitoes were in attack mode. I was not happy.
So it’s not the radios, the antennas, the audio panel, headsets, audio wiring…the only thing left was the audio connections between the SL-30 rack and the audio panel rack, plus the short little pigtail antenna connectors on the SL-30 rack.
Now, we had built this panel from scratch about a year and a half ago, and it had worked just fine until this recent problem. Most of the panel was new, but the SL-30 was a carryover from the old panel, Louise having bought it about three years ago with a pre-wired harness. The rack came with the Garmin right-angle BNC connectors prewired with 12” Coax pigtails terminated in Male BNC connectors. For those not familiar with the radio, it has two identical antenna connections, one for Comm and one for NAV, on opposite corners of the rack. The connectors are proprietary little buggers from Garmin with little mounting ears to screw them to the rack. They are the kind where you have to put the coax through from the side, and add one tiny drop of solder to join the center conductor of the connector to the center conductor of the Coax. Very ticklish little things. and impossible to find, except in an install kit from the “Big G”.
This evening, when Louise flew home from work, I pulled out my tools and dove once again under the panel. I was a man on a mission, with my headlamp lighting the way and tools in my mouth, It didn’t take too long to get the pigtail liberated from the rack, and over to the workbench. I unscrewed the cap, and began a forensic investigation.
As I unscrewed the nut that holds the outside braid to the connector body, I saw a curious thing – the center conductor was turning with the jacket – it wasn’t fixed to the blob of solder on the center post! Rather, it was turning WITHIN the blob of solder! It was not firmly attached – captured, but free to move. Given the incredibly hot temperatures we have been seeing, and the odd nature of RF problems, I became excited – I may not have found THE problem, but I sure found A problem! Out came the soldering iron, and I rebuilt the joint to specifications – nice and tight, with no movement, and no shorts (as checked by the DVM). Crawled back in the plane, invigorated by the fact that I’d actually found something, and had everything back together in 20 minutes. Ready for a test flight….which had to wait until the next day, as it was late, and I had "real" work to do...(which didn't pan out, unfortunately - hydrogen leaks are BAD!).
The next evening, Louise and I took off in both planes in quick succession for some in-flight testing, heading away from each other to check the range. Fifteen minutes later, we knew we had a winner - the radio was loud and clear, with no fading! I sure am glad that worked, 'cause if it hadn't, my next step was going to be to call an exorcist.....patience my eye....
Paul
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