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Electrical issues question
I realize that lots of theories may exist, and trouble shooting is a crap
shoot from afar but I am wondering, what would cause a full discharge indication when I put my landing light on. This started shortly b4 I had my radio put in, and when I flew it back from the avionics shop, on the short flight, figured to see if it was a fluke or was it real. So, this is not related to the radio installation. Seems that when I put my avionic switch on, amps hold. If I put my nav lights no strobe, slight discharge indication. Put my nave with strobes, same load. Put my landing light on and amps show a full discharge. Would it be my alternator can't take a full load? I don't get a chance to try this in reverse as when I put the landing light on without anything electrical on, it shows a full discharge. The landing light circuit is a 30 amp circuit. Does that seem like a rather large circuit for something as simple as a landing light? Or would it be something silly with my electrical wiring? Battery is only 2 years old, starts with one or two turns of the prop, so can't imagine it being the battery. Hope to get a hold of my A&P on Tuesday to get this resolved, but hoping for some wisdom from the group so I know what should be looked at. Allen |
#2
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Electrical issues question
"A Lieberman" wrote in message
.. . I realize that lots of theories may exist, and trouble shooting is a crap shoot from afar but I am wondering, what would cause a full discharge indication when I put my landing light on. .... Seems that when I put my avionic switch on, amps hold. If I put my nav lights no strobe, slight discharge indication. Put my nave with strobes, same load. Put my landing light on and amps show a full discharge. Would it be my alternator can't take a full load? Yup. Most likely, either your alternator is, to use the technical term, broken. Or, if it is belt driven, the belt is too loose. .... The landing light circuit is a 30 amp circuit. Does that seem like a rather large circuit for something as simple as a landing light? Landing lights use a lot of electricity. That's why they are so bright. 30 amps sounds about right. Hope to get a hold of my A&P on Tuesday to get this resolved, but hoping for some wisdom from the group so I know what should be looked at. Bummer being stuck on the ground 'till next week. -- Geoff the sea hawk at wow way d0t com remove spaces and make the obvious substitutions to reply by mail Spell checking is left as an excercise for the reader. |
#3
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Electrical issues question
Allen,
Check that you don't have any chaffed wires that haven't made a direct short yet but aare on the way. We have had several landing light issues that just turn out to be a broken wire or a bad ground. Remember to always check the simple things first because usually you hit paydirt!! Merry Christmas!! Jon Kraus '79 Mooney 201 4443H @ TYQ A Lieberman wrote: I realize that lots of theories may exist, and trouble shooting is a crap shoot from afar but I am wondering, what would cause a full discharge indication when I put my landing light on. This started shortly b4 I had my radio put in, and when I flew it back from the avionics shop, on the short flight, figured to see if it was a fluke or was it real. So, this is not related to the radio installation. Seems that when I put my avionic switch on, amps hold. If I put my nav lights no strobe, slight discharge indication. Put my nave with strobes, same load. Put my landing light on and amps show a full discharge. Would it be my alternator can't take a full load? I don't get a chance to try this in reverse as when I put the landing light on without anything electrical on, it shows a full discharge. The landing light circuit is a 30 amp circuit. Does that seem like a rather large circuit for something as simple as a landing light? Or would it be something silly with my electrical wiring? Battery is only 2 years old, starts with one or two turns of the prop, so can't imagine it being the battery. Hope to get a hold of my A&P on Tuesday to get this resolved, but hoping for some wisdom from the group so I know what should be looked at. Allen |
#4
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Electrical issues question
On Sun, 25 Dec 2005 01:31:01 GMT, Jon Kraus wrote:
Allen, Check that you don't have any chaffed wires that haven't made a direct short yet but aare on the way. We have had several landing light issues that just turn out to be a broken wire or a bad ground. Remember to always check the simple things first because usually you hit paydirt!! Merry Christmas Jon, Do you think it is much to just replace the wire from a landing light to the switch? I seem to have a gremlin in that landing light. When I bought the plane, had a very minor electrical fire (smoke and the unpleasant smell of something burning, no flames) where the insolation burned at the switch. I had isolated to the toggle switch as it was mighty warm to the touch. Turned the switch off, and that resolved the problem til I landed. :-) Of course, the "no landing light" training kicked in and it was really a non event. Replaced the switch and the problem went away until now. Garmin 430 is in, but still have some issues to be taken care of. When I transmit, I get a scratchy sound via the side tone. Asked ATC and Unicom how my transmission was, and they said nice and clear. 2nd com, the sound is very weak, and I can't tell if I am transmitting strongly or not. Ended up going back to COM one while climbing out talking with tower. So, will check back with the avionics guy when he returns from vacation after the first of the year. May just go ahead and get a new COM2 when I take it back. After 11.5 AMU's, whats another 2.5? Nothing simple with airplane ownership..... Allen |
#5
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Electrical issues question
Allen,
I would guess that unless your wiring for the landing light is complicated they should be able to run a new wire in an hour or so. For our Mooney the light switch has a built in breaker that trips whenever there is a problem. I bet we've had to ahve the wire fixed three times since we bought 4443H. Each time is is a very simple repair. As far as your second comm goes (I'm not sure what is in your Sundowner) but you should look into TKM MX Series NAV/COMS. They are direct slide-in, plug-and-play replacements for King KX 170B, Cezzna 300 series and Narco radios. You can pick up the King replacement (they call it MX 170C) for about 1.5 AMU's and save yourself 1 AMU. When our 2nd 170B craps out that is exactly what I am going to do. I've asked around and people have good things to say about them. I had never heard of them before I started looking into replacing our 170B. Here is a link so you can see for yourself. Merry Christmas to you too!! http://www.avionix.com/navcoms.html Jon Kraus '79 Mooney 201 4443H @ TYQ A Lieberman wrote: On Sun, 25 Dec 2005 01:31:01 GMT, Jon Kraus wrote: Allen, Check that you don't have any chaffed wires that haven't made a direct short yet but aare on the way. We have had several landing light issues that just turn out to be a broken wire or a bad ground. Remember to always check the simple things first because usually you hit paydirt!! Merry Christmas Jon, Do you think it is much to just replace the wire from a landing light to the switch? I seem to have a gremlin in that landing light. When I bought the plane, had a very minor electrical fire (smoke and the unpleasant smell of something burning, no flames) where the insolation burned at the switch. I had isolated to the toggle switch as it was mighty warm to the touch. Turned the switch off, and that resolved the problem til I landed. :-) Of course, the "no landing light" training kicked in and it was really a non event. Replaced the switch and the problem went away until now. Garmin 430 is in, but still have some issues to be taken care of. When I transmit, I get a scratchy sound via the side tone. Asked ATC and Unicom how my transmission was, and they said nice and clear. 2nd com, the sound is very weak, and I can't tell if I am transmitting strongly or not. Ended up going back to COM one while climbing out talking with tower. So, will check back with the avionics guy when he returns from vacation after the first of the year. May just go ahead and get a new COM2 when I take it back. After 11.5 AMU's, whats another 2.5? Nothing simple with airplane ownership..... Allen |
#6
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Electrical issues question
A Lieberman writes:
I realize that lots of theories may exist, and trouble shooting is a crap shoot from afar but I am wondering, what would cause a full discharge indication when I put my landing light on. Which kind of ammeter? Zero-center, or only alternator output? I'll guess zero center here. Seems that when I put my avionic switch on, amps hold. If I put my nav lights no strobe, slight discharge indication. Put my nave with strobes, same load. Put my landing light on and amps show a full discharge. Would it be my alternator can't take a full load? Possible. But let's run some tests. Compare what happens with various loads at near-idle, and at run-up. The alternator will make power at idle; but not its full rated output. After running the landing light for a minute or so at idle, turn it off and increase RPM. Does the alternator recharge the battery, then back down again? I don't get a chance to try this in reverse as when I put the landing light on without anything electrical on, it shows a full discharge. What is "full"? 30A? or is the ammeter unmarked? The landing light circuit is a 30 amp circuit. Does that seem like a rather large circuit for something as simple as a landing light? Nope, it take amps to make foot-candles. 30A is quite reasonable for a headlamp breaker. Or would it be something silly with my electrical wiring? Battery is only 2 years old, starts with one or two turns of the prop, so can't imagine it being the battery. It could be: loose belt poor grounds/loose wiring on alternator/elsewhere. bad alternator diodes {do you hear a whine in the audio?} It's not a battery issue. I was driving a borrowed CRX to a friend's funeral when it stopped dead on the PA Turnpike. The plug on the alternator [small wires for field, etc] had come loose. I was quite fortunately at the top of a hill, as the battery was down to 10V per my DVM. Even after roll-starting the car, and watching the voltage ...slowly.. increase, it could barely keep up with the headlamps on. Made it to my BiL's and then found the nut on the output lead was loose; I burned my finger touching it. Loose == voltage drop == I^R == heat; that 10mm nut was dispersing ~50 watts by my guess. Both my fault; as I'd replaced the alternator bearing for the owner weeks before. -- A host is a host from coast to & no one will talk to a host that's close........[v].(301) 56-LINUX Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433 |
#7
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Electrical issues question
On Sun, 25 Dec 2005 16:02:55 +0000 (UTC), David Lesher wrote:
A Lieberman writes: I realize that lots of theories may exist, and trouble shooting is a crap shoot from afar but I am wondering, what would cause a full discharge indication when I put my landing light on. Which kind of ammeter? Zero-center, or only alternator output? I'll guess zero center here. Zero center would be my guess. Zero is at the top and needle is centered, and I *think* it goes up to 40 plus on the right, and 40 minus on the left? Possible. But let's run some tests. Compare what happens with various loads at near-idle, and at run-up. The alternator will make power at idle; but not its full rated output. Same symptoms at cruise or at idle. Same needle deflection visually, maybe *very slightly* less at cruise RPM. After running the landing light for a minute or so at idle, turn it off and increase RPM. Does the alternator recharge the battery, then back down again? As soon as I turn the landing light off, the needle jumps back to just below the zero indication. Turn off the nav lights, and the ammeter indicates normal level at zero. What is "full"? 30A? or is the ammeter unmarked? Not sure what the full load is, but going on memory, I thought 40 came to mind.... Needle is just about full throw to the left. Or would it be something silly with my electrical wiring? Battery is only 2 years old, starts with one or two turns of the prop, so can't imagine it being the battery. It could be: loose belt poor grounds/loose wiring on alternator/elsewhere. bad alternator diodes {do you hear a whine in the audio?} Yes, I do hear a whine only on startup. After the prop turns, if it is there, I don't hear it. Understanding costs vary, how much would I be looking at should it be an alternator? Lycoming AK4 360 180 hp is my engine. Allen |
#8
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Electrical issues question
A Lieberman wrote:
Ah yes, the electrical gremlins. We just finished rebuilding/replacing our charging system. Every so often, the voltage would be 12.4-12.5 volts or so after first engine start of the day. After 1/2 hour of flying, it would be back up to around 13.1 or so. Turned out that our alternator needed to be rebuilt and the voltage regulator and over voltage relay were toast. Garmin 430 is in, Very nice. Is that Allen saying "Merry Christmas to me"? May just go ahead and get a new COM2 when I take it back. After 11.5 AMU's, whats another 2.5? Peanuts. Well, ok, a lot of them...but...in aviation/AMU terms, (almost) a drop in the bucket :-) I think you'll like the 430 Allen. I keep finding new stuff with ours. Helps that my CFII knows the unit very well. -- Jack Allison PP-ASEL-IA Student Arrow N2104T "When once you have tasted flight, you will forever walk the Earth with your eyes turned skyward, for there you have been, and there you will always long to return" - Leonardo Da Vinci (Remove the obvious from address to reply via e-mail) |
#9
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Electrical issues question
Don't overlook the inexpensive link of the alternator power switch.
This switch carries a lot of current and arcing can over time cause the switch to deteriorate. This reduces field current to the alternator and reduced performance. |
#10
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UPDATE Electrical issues question (was: Electrical issues question)
On Sat, 24 Dec 2005 13:40:46 -0600, A Lieberman wrote:
I realize that lots of theories may exist, and trouble shooting is a crap shoot from afar but I am wondering, what would cause a full discharge indication when I put my landing light on. Update, newsflash, the whole niner yards.... Defective alternator was the final verdict. A$P ordered another one and I should be flying tomorrow afternoon (I hope!). Allen |
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