Avionics (Radio Problem) Narrowed Down... I Think???

Will do.... Thanks Mark!

OK, now take that old relay, get a piece of bond copy paper and some pure
isopropyl (the 99% stuff) alcohol, tear/cut a strip of the bond paper about
a quarter of an inch wide, soak the first two inches of the paper in the
alcohol, and run the paper between EACH of the contacts of the old relay,
holding pressure on the top and bottom contact just enough so that the paper
doesn't tear.

You will find as the contacts leave the alcohol part of the paper a strip of
black "gunk" down the dry part of the paper. Keep running the paper through
these contacts until the paper no longer has a black stripe on it -- and
then go to the next set of contacts. Don't forget to do BOTH sets of
contacts on a pole -- the upper and lower both get equally dirty.

Now do the NEXT set of contacts and so on. You now have a perfectly clean
relay for the next time the new one honks up.

(BTW, this trick works for switches, relays, and anywhere else you have a
relatively low current set of contacts.)

Do NOT use a file or a "relay contact cleaner" strip. These will peel any
precious metal plating off in the first swipe.

Jim


"three-eight-hotel" wrote in message
oups.com...
Received a new relay on Wednesday, plugged it into the audio panel and
slid the audio panel back into the stack this morning.

Thanks! I will do that...

Off topic question:

The audio panel from the front, has every indication that it has marker
beacons (O, M, I indicators), but there's nothing there... Simply no
led's or wires to the panel. This would seem like a fairly simple
thing to implement??? Should I just cut my losses and be happy I can
communicate, or am I getting greedy, thinking I could go to Radio Shack
and with minimal effort, upgrade this existing audio panel by myself?

If you think it's not worth the effort, I'll close this thread and open
a new one on how to repack and seal the front nose strut, or how to
find the source for fuel in the cabin smell after topping the tanks, or
tip tanks... Keep em' full or not??? :-))

Thanks!
Todd

RST Engineering wrote:
: OK, now take that old relay, get a piece of bond copy paper and some pure
: isopropyl (the 99% stuff) alcohol, tear/cut a strip of the bond paper about
: a quarter of an inch wide, soak the first two inches of the paper in the
: alcohol, and run the paper between EACH of the contacts of the old relay,
: holding pressure on the top and bottom contact just enough so that the paper
: doesn't tear.


I find old business cards are just the right thickness & strength to handle
this task. Since my old company changed area codes, then logos, I have enough
old business cards to last a few lifetimes.
--
Aaron C.

: : OK, now take that old relay, get a piece of bond copy paper and some pure
: : isopropyl (the 99% stuff) alcohol, tear/cut a strip of the bond paper about
: : a quarter of an inch wide, soak the first two inches of the paper in the
: : alcohol, and run the paper between EACH of the contacts of the old relay,
: : holding pressure on the top and bottom contact just enough so that the paper
: : doesn't tear.


: I find old business cards are just the right thickness & strength to handle
: this task. Since my old company changed area codes, then logos, I have enough
: old business cards to last a few lifetimes.
: --
IIRC, the Bendix mag service instructions allow for cleaning of the points
using exactly that... a business card. Note, however, that pulling it through is
*NOT* allowed... simply closing the points on it and opening it back up.

I think that it has to do with the microscopic roughness on the mating
surfaces. Once they've "worn in," dragging a card through will cause the "teeth" not
to mate anymore.

-Cory

--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

You might be able to find light bulbs at The Shack, but more probably would
be a model train shop for 12 volt grain-of-wheat lamps.

Jim



"three-eight-hotel" wrote in message
ups.com...
Thanks! I will do that...

Off topic question:

The audio panel from the front, has every indication that it has marker
beacons (O, M, I indicators), but there's nothing there... Simply no
led's or wires to the panel. This would seem like a fairly simple
thing to implement??? Should I just cut my losses and be happy I can
communicate, or am I getting greedy, thinking I could go to Radio Shack
and with minimal effort, upgrade this existing audio panel by myself?

"three-eight-hotel" writes:

Thanks! I will do that...

Off topic question:

The audio panel from the front, has every indication that it has marker
beacons (O, M, I indicators), but there's nothing there... Simply no
led's or wires to the panel. This would seem like a fairly simple
thing to implement??? Should I just cut my losses and be happy I can
communicate, or am I getting greedy, thinking I could go to Radio Shack
and with minimal effort, upgrade this existing audio panel by myself?

Does the panel have the decoders; just no indicators? It could be
the PCB section for that function was never populated, or it's a
daughter board that was not installed...


--
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

hmmm...??? If you followed any of my previous posts, you wouldn't be
surprised that I don't know what decoders or PCB's are... LOL!!! ;-)

The holes for the tri-colored lights are on the panel and labeled, but
there is nothing behind them. No led's, no wires... Is there an
entire daughter board that runs the MB's? I may be biting off more
than I can chew, but looking at pics of other Cessna audio panels
on-line, it just looked like there were led's and wires running to the
main board, but it was hard to tell...

Thanks,
Todd

three-eight-hotel wrote:
hmmm...??? If you followed any of my previous posts, you wouldn't be
surprised that I don't know what decoders or PCB's are... LOL!!! ;-)

The holes for the tri-colored lights are on the panel and labeled, but
there is nothing behind them. No led's, no wires... Is there an
entire daughter board that runs the MB's? I may be biting off more
than I can chew, but looking at pics of other Cessna audio panels
on-line, it just looked like there were led's and wires running to the
main board, but it was hard to tell...

I've got the Marker Beacon receiver out of a Tomahawk if you need one,
don't have the pin outs for it though, its a TKM unit...

three-eight-hotel wrote:
/snip/
If you think it's not worth the effort, I'll close this thread and open
a new one on how to repack and seal the front nose strut, or how to
find the source for fuel in the cabin smell after topping the tanks, or
tip tanks... Keep em' full or not??? :-))

Thanks!
Todd


Todd,

Close this thread now! Those old Cessna audio panels (actually, just
switching panels) were junk the day they were new, and have NOT improved
with age. To make the marker beacons work, you need a marker receiver
box (R403B, IIRC), plus all the associatd wiring, PLUS the missing
components on your "audio panel".

IMHO, it's not worth it. Stop putting any money in to the unit you
have, and save up for a true upgrade, when you "just gotta have"
improved capability.

Happy Flying!
Scott Skylane
N92054