182RG question

I am hoping to tap some of the expertise here to solve a problem I have run
into.

I am a retired guy who was called by a local Part 141 school to fill in as
their flightline mechanic until they could find a permanent A&P. They have
an early 182RG (serial 141) that has an ongoing electrical problem.

My first question concerns the ammeter. I have definitely confirmed that the
ammeter is defective. It appears like the ENTIRE gage cluster will have to
be replaced. The parts manual shows that the original gage is not available.
A supersession was listed which also consisted of a single gage. However
when this was pursued it was not available as a single replacement.

So my question is has anyone come up with a solution for a single defective
gage in this cluster that does not involve replacing the entire thing? How
about an instrument shop that would rebuild the ammeter? I have been unable
to find an instrument shop that would bother with an ammeter.


Here's my second question. I think the reason the ammeter broke is that it
simply wore out. The voltage and hence the current is constantly varying.
The original ammeter needle was oscillating so much that you couldn't tell
if the system was charging or not. I put a test ammeter in series and the
although the ammeter could be read, it was still oscillating. A check with
an analog meter showed fluctuations that increased in frequency as the RPM
was increased. Ditto for increasing the load. A scope shows about 900 mv
peak.

Persons before me have replaced the alternator and regulator. (a note here,
the regulator is the simple 3 wire unit)
All grounds were cleaned and remade.

Any hints of where I should begin my search would be greatly appreciated. I
have to pull this beast out of the hanger to run it up. With out Northwest
weather I haven't had two clear days to work on it outside and I'm too old
and stiff to do a lot under the panel. So any hints or experience of a
similar trouble would really be appreciated.

I'm going to jumper the alternator field portion of the dual master switch
to start with but beyond that ----------------


Thanks in advance

Paul Anton

Have you tried posting to a type club for the Cessna 182 line? They are
full of great ideas such as you are asking.

I know there is a general Cessna club for such things.

Kobra


"Paul Anton" wrote in message
...
I am hoping to tap some of the expertise here to solve a problem I have run
into.

I am a retired guy who was called by a local Part 141 school to fill in as
their flightline mechanic until they could find a permanent A&P. They have
an early 182RG (serial 141) that has an ongoing electrical problem.

My first question concerns the ammeter. I have definitely confirmed that
the ammeter is defective. It appears like the ENTIRE gage cluster will
have to be replaced. The parts manual shows that the original gage is not
available. A supersession was listed which also consisted of a single
gage. However when this was pursued it was not available as a single
replacement.

So my question is has anyone come up with a solution for a single
defective gage in this cluster that does not involve replacing the entire
thing? How about an instrument shop that would rebuild the ammeter? I have
been unable to find an instrument shop that would bother with an ammeter.


Here's my second question. I think the reason the ammeter broke is that it
simply wore out. The voltage and hence the current is constantly varying.
The original ammeter needle was oscillating so much that you couldn't tell
if the system was charging or not. I put a test ammeter in series and the
although the ammeter could be read, it was still oscillating. A check with
an analog meter showed fluctuations that increased in frequency as the RPM
was increased. Ditto for increasing the load. A scope shows about 900 mv
peak.

Persons before me have replaced the alternator and regulator. (a note
here, the regulator is the simple 3 wire unit)
All grounds were cleaned and remade.

Any hints of where I should begin my search would be greatly appreciated.
I have to pull this beast out of the hanger to run it up. With out
Northwest weather I haven't had two clear days to work on it outside and
I'm too old and stiff to do a lot under the panel. So any hints or
experience of a similar trouble would really be appreciated.

I'm going to jumper the alternator field portion of the dual master switch
to start with but beyond that ----------------


Thanks in advance

Paul Anton

Any digital options?

.....


Any hints of where I should begin my search would be greatly
appreciated. I
have to pull this beast out of the hanger to run it up. With out
Northwest
weather I haven't had two clear days to work on it outside and I'm
too old
and stiff to do a lot under the panel. So any hints or experience of
a
similar trouble would really be appreciated.

I'm going to jumper the alternator field portion of the dual master
switch
to start with but beyond that ----------------


Thanks in advance

Paul Anton

May want to check with Paul Malkasian up in Sequim, (360)683-6245, he
has a very good reputation for rebuilding all kinds of OEM Cessna
gauges. Also, before further experimentation, verify you do not have an
automotive regulator - VERY bad deal on airplanes. Unlike aircraft
units, turning off power to the S pin (turning off half of a split
master) does not cut field to the alternator, but shuts off the
regulator itself, resulting in easy 90-100V out of a healthy alternator
at high RPM.

Don't overlook something as simple as a slipping belt.

Paul Anton wrote:

I am hoping to tap some of the expertise here to solve a problem I have run
into.

I am a retired guy who was called by a local Part 141 school to fill in as
their flightline mechanic until they could find a permanent A&P. They have
an early 182RG (serial 141) that has an ongoing electrical problem.

My first question concerns the ammeter. I have definitely confirmed that the
ammeter is defective. It appears like the ENTIRE gage cluster will have to
be replaced. The parts manual shows that the original gage is not available.
A supersession was listed which also consisted of a single gage. However
when this was pursued it was not available as a single replacement.

So my question is has anyone come up with a solution for a single defective
gage in this cluster that does not involve replacing the entire thing? How
about an instrument shop that would rebuild the ammeter? I have been unable
to find an instrument shop that would bother with an ammeter.


Here's my second question. I think the reason the ammeter broke is that it
simply wore out. The voltage and hence the current is constantly varying.
The original ammeter needle was oscillating so much that you couldn't tell
if the system was charging or not. I put a test ammeter in series and the
although the ammeter could be read, it was still oscillating. A check with
an analog meter showed fluctuations that increased in frequency as the RPM
was increased. Ditto for increasing the load. A scope shows about 900 mv
peak.

Persons before me have replaced the alternator and regulator. (a note here,
the regulator is the simple 3 wire unit)
All grounds were cleaned and remade.

Any hints of where I should begin my search would be greatly appreciated. I
have to pull this beast out of the hanger to run it up. With out Northwest
weather I haven't had two clear days to work on it outside and I'm too old
and stiff to do a lot under the panel. So any hints or experience of a
similar trouble would really be appreciated.

I'm going to jumper the alternator field portion of the dual master switch
to start with but beyond that ----------------


Thanks in advance

Paul Anton


I have a Cessan-172 that had a serious ammeter swinging problem. Mine is
the '65 model with the push-pull switches for the master. My A&P
installed a mil grade DPST toggle switch. No reoccuring problems. The
Cessna switch had enough resistance in the alternator side of the switch
(this model does not have the split switch) to disrupt the regulator. If
you ever take one apart, you will see how cheaply they are made.

--
Regards, Ross
C-172F 180HP

I'm not an A&P, but have some electronics/electricals background.
Normally when you see that much oscillation in a ammeter, its either
the diodes in the alternator or the voltage regulator.

A local school was having the same problem with a recently acquired
Cherokee -- the neddle swung back and forth a good 10-15 amps varying
as the load changed. Got to checking and found an unmarked voltage
regulator in it. Checked with the owner who says "Oh yea, its from a
Saab! Works good, doesn't it?"

So, don't discount a wrong part in it. Just because its "worked"
doesn't mean its the right part.


Chuck



On Wed, 11 May 2005 18:30:35 -0700, "Paul Anton"
wrote:

I am hoping to tap some of the expertise here to solve a problem I have run
into.

I am a retired guy who was called by a local Part 141 school to fill in as
their flightline mechanic until they could find a permanent A&P. They have
an early 182RG (serial 141) that has an ongoing electrical problem.

My first question concerns the ammeter. I have definitely confirmed that the
ammeter is defective. It appears like the ENTIRE gage cluster will have to
be replaced. The parts manual shows that the original gage is not available.
A supersession was listed which also consisted of a single gage. However
when this was pursued it was not available as a single replacement.

So my question is has anyone come up with a solution for a single defective
gage in this cluster that does not involve replacing the entire thing? How
about an instrument shop that would rebuild the ammeter? I have been unable
to find an instrument shop that would bother with an ammeter.


Here's my second question. I think the reason the ammeter broke is that it
simply wore out. The voltage and hence the current is constantly varying.
The original ammeter needle was oscillating so much that you couldn't tell
if the system was charging or not. I put a test ammeter in series and the
although the ammeter could be read, it was still oscillating. A check with
an analog meter showed fluctuations that increased in frequency as the RPM
was increased. Ditto for increasing the load. A scope shows about 900 mv
peak.

Persons before me have replaced the alternator and regulator. (a note here,
the regulator is the simple 3 wire unit)
All grounds were cleaned and remade.

Any hints of where I should begin my search would be greatly appreciated. I
have to pull this beast out of the hanger to run it up. With out Northwest
weather I haven't had two clear days to work on it outside and I'm too old
and stiff to do a lot under the panel. So any hints or experience of a
similar trouble would really be appreciated.

I'm going to jumper the alternator field portion of the dual master switch
to start with but beyond that ----------------


Thanks in advance

Paul Anton

On Wed, 11 May 2005 18:30:35 -0700, "Paul Anton"
wrote:

My first question concerns the ammeter. I have definitely confirmed that
the
ammeter is defective. It appears like the ENTIRE gage cluster will have to
be replaced.

Here's my second question. I think the reason the ammeter broke is that it
simply wore out.

Paul, I've started working in avionics and aircraft electrical systems in
1979. I've never seen an ammeter "wear out".

The voltage and hence the current is constantly varying.
The original ammeter needle was oscillating so much that you couldn't tell
if the system was charging or not.

Seems to me that if you verified that the current was oscillating, the
ammeter is not broken. I would suggest that you pull circuit breakers and
see if you can isolate what system is making the ammeter oscillate like
that. If your alternator and regulator have been recently replaced and they
check out OK, there aren't that many systems in a 182RG that can make the
ammeter behave that way.

Juan Jimenez wrote:

On Wed, 11 May 2005 18:30:35 -0700, "Paul Anton"
wrote:


My first question concerns the ammeter. I have definitely confirmed that
the
ammeter is defective. It appears like the ENTIRE gage cluster will have to
be replaced.

Here's my second question. I think the reason the ammeter broke is that it
simply wore out.


Paul, I've started working in avionics and aircraft electrical systems in
1979. I've never seen an ammeter "wear out".


The voltage and hence the current is constantly varying.
The original ammeter needle was oscillating so much that you couldn't tell
if the system was charging or not.


Seems to me that if you verified that the current was oscillating, the
ammeter is not broken. I would suggest that you pull circuit breakers and
see if you can isolate what system is making the ammeter oscillate like
that. If your alternator and regulator have been recently replaced and they
check out OK, there aren't that many systems in a 182RG that can make the
ammeter behave that way.


A Cessna master switch can cause the problem. See earlier post.

--
Regards, Ross
C-172F 180HP

"Ross Richardson" wrote in message
...
Juan Jimenez wrote:

On Wed, 11 May 2005 18:30:35 -0700, "Paul Anton"
wrote:


My first question concerns the ammeter. I have definitely confirmed that
the
ammeter is defective. It appears like the ENTIRE gage cluster will have
to
be replaced.

Here's my second question. I think the reason the ammeter broke is that
it
simply wore out.


Paul, I've started working in avionics and aircraft electrical systems in
1979. I've never seen an ammeter "wear out".


The voltage and hence the current is constantly varying.
The original ammeter needle was oscillating so much that you couldn't
tell
if the system was charging or not.


Seems to me that if you verified that the current was oscillating, the
ammeter is not broken. I would suggest that you pull circuit breakers and
see if you can isolate what system is making the ammeter oscillate like
that. If your alternator and regulator have been recently replaced and
they check out OK, there aren't that many systems in a 182RG that can
make the ammeter behave that way.
A Cessna master switch can cause the problem. See earlier post.

--
Regards, Ross
C-172F 180HP

I saw that, but the problem is that it is not legal to replace the master
switch with a "military" switch unless it is FAA approved. That is not to
say that it can't be done, but my guess is that if this is truly the root
cause of the problem, Cessna would have already issued an SB and an
alternate p/n for a replacement switch.

Juan