King KT76A KT76 mounting tray

[Brian2034]

Ancient history I know!
Can one of our avionics gurus explain the difference between the 76 and the 76A transponder mounting tray/ back plate. I know the transponder is ancient and needs an upgrade into this century. But I'm  just looking to get the Mooney up an flying this year and then decide on future updates.

[Yetti]

 

[Brian2034]

Thank you,

I’ve read that thread but it doesn’t tell me what I need.

 

[N201MKTurbo]

You need to get the install manuals for both and see what is different. 

[65MooneyPilot]

I just looked at the IM manuals and it looks like the connector on the KT76A has more connections and is different. The trays have different p/n’s. KT76 only has 12 connections and the KT76A has 15 connections. The connectors are labeled differently with letters and the KT76 are numbers.

[Aaviationist]

There isn’t a scenario where just putting in a modern transponder isn’t a better idea. 

[wombat]

Meh....  I think there are scenarios where tossing in another old one makes sense. Not many...

If you are planning an upgrade to a transponder that you can't use now (say a GTX-345R remote transponder) but don't want to install the GTN-750 right now. Or if you already have the KT-76A and plenty of spares for it, and the labor to do the install is cheap.

But maybe I'm making excuses because I nearly did the same thing.  I didn't end up doing it, but was pretty close.

Yes, the pinouts between the two transponders (KT76 and KT76A) are different.  Annoying.  I don't know if they are physically compatible, but I do know they are not plug and play.

 

I was able to upgrade to a Garmin GTX-327 with very minimal effort.   I think it was a total of about 20 pins that I had to make.  I'm really glad I did that.

 

[N201MKTurbo]

If you are thinking of moving to a KT76A from a KT76, just remove the pins from the old connector and insert them Into the new connector. 
 

No matter who does the work, you will need a transponder cert after it is done.

[Aaviationist]

9 minutes ago, wombat said:

Meh....  I think there are scenarios where tossing in another old one makes sense. Not many...

 

There are none if you don’t have the correct tray, or wiring. 

[wombat]

Well, you can't install anything without the correct tray, or wiring.

But a KT-76A with tray and wiring can be had pretty cheap.  If you have some local airport friends they might give you one for free.

There is a KT-76A tray and wiring on ebay right now for $75.    So this is probably just a couple of hours of work to make the thing operational.

[MikeOH]

1 hour ago, Aaviationist said:

There isn’t a scenario where just putting in a modern transponder isn’t a better idea. 

BS

My KT76A died a couple of years into ownership. I found one on eBay for $125 and had my A&P swap it and the got the cert. Total cost was $300. Still working fine 5 years later. I already had a TailBeacon for ADSB-out and a Scout for in.

No way spending multiple AMUs would have been a “better idea”!

[Brian2034]

I have a KT76A that’s questionable and was thinking of going with a AT165 that’s available but it’s labeled as a KT76 upgrade, not a A

[Brian2034]

Thank you 65 Mooney Pilot

Looks like it’s just a simple repin to interchange a 76 /76A

[A64Pilot]

44 minutes ago, MikeOH said:

BS

My KT76A died a couple of years into ownership. I found one on eBay for $125 and had my A&P swap it and the got the cert. Total cost was $300. Still working fine 5 years later. I already had a TailBeacon for ADSB-out and a Scout for in.

No way spending multiple AMUs would have been a “better idea”!

I bought my Mooney it had an old KT-76A in it, worked but wasn’t a digital display and of course didn’t display the alt I was transmitting. It simply just didn’t match the rest of the radios.

A yellow tagged kT-76C was maybe a couple of hundred bucks, slides right in and is plug n play with an A.

What I can’t wrap my head around is all these people that spend tens of thousands of bucks on new glass, when their engine is past TBO, sure it may last a little longer but the clocks ticking.

I just don’t fly IFR anymore and my dual ILS, with Garmin 430 old King instruments is just what I want, and guess what, I can still buy replacements cheap, and or still have the old King stuff repaired, but bet the much newer 430 if it’s not already but soon won’t be supported anymore.

[Aaviationist]

4 hours ago, MikeOH said:

BS

My KT76A died a couple of years into ownership. I found one on eBay for $125 and had my A&P swap it and the got the cert. Total cost was $300. Still working fine 5 years later. I already had a TailBeacon for ADSB-out and a Scout for in.

No way spending multiple AMUs would have been a “better idea”!

You are talking about a direct swap replacement. Yes that makes sense. 
 

but when you don’t have the tray or connector and you newly install that radio, as I said, no. That does not make sense.