KT-76A transponder is flakey

My KT-76A transponder stops working after an hour or so of use. If I pull
it out, it feels very hot to the touch. I was thinking of buying another
transponder off ebay. Can I just slide mine out and another in myself ?
What other transponders are pin and slide-in compatible ?

Thanks !
Peter
N1447U

"Peter Hoeve" wrote in
news:mD7rb.145589$Fm2.125604@attbi_s04:

My KT-76A transponder stops working after an hour or so of use. If I
pull it out, it feels very hot to the touch. I was thinking of buying
another transponder off ebay. Can I just slide mine out and another
in myself ? What other transponders are pin and slide-in compatible ?

Legally the transponder is the only one you can NOT do this to. The entire
*system* is suppose to be certified together.

Frankly, however, and especially if you are VFR only, then there are "some
pilots" who would plug it in and do a test flight. On the test flight have
the local approach control give you a transponder readout at a couple of
different altitudes. If this looks good, it probably is good.

But that's just "some pilots." Seriously, the correct thing to do is to
have a shop do stick it in and do the certification, with appropriate
logbook entry. Will cost about $200.

-----------------------------------------------
James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721
-----------------------------------------------

"James M. Knox" wrote in message ...

Legally the transponder is the only one you can NOT do this to. The entire
*system* is suppose to be certified together. '

In addition to the certification issue, the transponder is excluded from the
owner maintenance.

But that's just "some pilots." Seriously, the correct thing to do is to
have a shop do stick it in and do the certification, with appropriate
logbook entry. Will cost about $200.

The transponder itself will probably only run half of that...unless you
managed to muck with the encoder or the static system in the process.

Ron, Ron, Ron...

What happened to your mantra from years past...

The transponder connected to the #1 circuit breaker
The circuit breaker connected to the battery bus
The battery bus connected to the #2 circuit breaker
The circuit breaker connected to the landing light

So you are simply troubleshooting the landing light circuit, yes?

{;-)


"Ron Natalie"
shared these priceless pearls of wisdom:


-
-In addition to the certification issue, the transponder is excluded from the
-owner maintenance.



Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

"Peter Hoeve" wrote:

My KT-76A transponder stops working after an hour or so of use.

Could just be the oscillator tube getting out of alignment as it expands as
it gets hotter. I had the opposite problem -- my KT76A wouldn't work on cold
mornings until it had warmed up -- and it didn't even take an hour of bench
time to get the thing adjusted into spec. Of course, I'm no expert, so ask
you local friendly avionics shop what they think, but it could easily be
something that simple...

--
Mike Granby, PP-ASEL,IA
Warrior N44578
http://www.mikeg.net/plane

I thought the FARs explicitly prohibited the transponder.

Jim Weir wrote:

Ron, Ron, Ron...

What happened to your mantra from years past...

The transponder connected to the #1 circuit breaker
The circuit breaker connected to the battery bus
The battery bus connected to the #2 circuit breaker
The circuit breaker connected to the landing light

So you are simply troubleshooting the landing light circuit, yes?

{;-)

"Ron Natalie"
shared these priceless pearls of wisdom:

-
-In addition to the certification issue, the transponder is excluded from the
-owner maintenance.

Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

--
--Ray Andraka, P.E.
President, the Andraka Consulting Group, Inc.
401/884-7930 Fax 401/884-7950
email
http://www.andraka.com

"They that give up essential liberty to obtain a little
temporary safety deserve neither liberty nor safety."
-Benjamin Franklin, 1759

"Ray Andraka" wrote in message ...
I thought the FARs explicitly prohibited the transponder.

It prohibits it under the "remore and replace radios" clause.
However, if we're diagnosing faults in the landing light circuit....