Today's Message Index:
----------------------
0. 09:39 AM - Coming Soon - The List of Contributors - Please Make A Contribution Today! (Matt Dralle)
1. 09:41 PM - Troubleshooting radio whine/noise on Cessna 182P (sacha)
Message 0
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Coming Soon - The List of Contributors - Please Make |
A Contribution Today!
Each year at the end of the List Fund Raiser, I post a message acknowledging everyone
that so generously made a Contribution to support the Lists. Its my way
of publicly thanking everyone that took a minute to show their appreciation
for the Lists.
Please take a moment and assure that your name is on that List of Contributors
(LOC)! As a number of members have pointed out over the years, the List seems
at least as valuable a building / entertainment tool as your typical magazine
subscription!
Assure that your name is on this year's LOC! Show others that you appreciate the
Lists. Making a Contribution to support the Lists is fast and easy using your
Credit card or Paypal on the Secure Web Site:
http://www.matronics.com/contribution
or by dropping a personal check in the mail to:
Matt Dralle / Matronics
581 Jeannie Way
Livermore CA 94550
I would like to thank everyone that has so generously made a Contribution thus
far in this year's List Fund Raiser! Remember that its YOUR support that keeps
these Lists going and improving! Don't forget to include a little comment about
how the Lists have helped you!
Best regards,
Matt Dralle
Matronics Email List Administrator
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Troubleshooting radio whine/noise on Cessna 182P |
Hi Folks,
it's been a while since I've posted - it's nice to be back. I am the maintenance
officer of a flying club which recently purchased a 1972 Cessna 182P and I've
recently been quite busy... here is the story:
A week ago I was flying VFR at night and the alternator breaker popped in flight.
Luckily the battery had just been replaced and I was close to the airport
so I was able to land without further incident.
After I landed I reset the ALT breaker and noticed a whine in the headset and a
low (12.9V bus voltage). The whine varies in pitch with RPM and in volume with
electrical load (eg. when I turn on the landing lights).
I replaced the alternator and that made no difference to either the whine or the
low voltage. I then replaced the alternator regulator and bus voltage is back
up to 14.1V but the whine is unchanged.
Recent changes to the aircraft include:
- new Slick magnetos (a month ago, right after purchasing a/c)
- new battery (the day before the alternator failed), as previous battery appeared
dead (had the charging system been broken for a while?)
It all sounds like it could be the result of some kind of ground loop but I can't
quite see how that hypothesis fits with the history of the problems.
Does anyone have any ideas?
Sacha
PS. I've been reading the AeroElectric connection chapter 16 and based on that,
here are the next tests I plan to do:
a. Turn off alternator switch and see if noise disappears
b. Disconnect antenna or turn down radio volume and see if noise disappears (means
its entering the system through the antenna and not through the wiring)
c. Check whether the phone and mic jacks are insulated from the (metal) airframe
(but that's not something that recently changed, so unlikely to be the cause)
d. If noise not generated by Alternator, suspect mags:
i. try turning off one mag in turn and see if noise disappears.
ii. Try disconnecting the p-leads and see if noise disappears.
iii. Otherwise spark plug harnesses might be suspect and should be tested for
conductivity.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=449962#449962
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|