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

"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.

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

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

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

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

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

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)

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.

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