Best options for dealing with a flakey KNS-80. (Replace with used/upgrade?)

[johncuyle]

I recently purchased a 231.  Its primary nav is a KNS-80.  The unit is flakey.  It worked for about 80% of the flight home, then went into a weird state where it seemed to cycle modes randomly and lose any configured VOR frequencies, etc.  It now randomly works fine or does that.  I need to do something about it before I can fly in IMC.  My first COM is also not great.  The com really isn't too bad, just noisy.  I'm trying to figure out what my best option is.  I'm fine flying with the KNS-80.  It's easy to use, and has a decent feature set, so lowest cost option, assuming it is the unit itself and not the connector on the rack or wiring behind it, would be to swap it out for another used one.  I'm new to plane ownership and curious what others would do in this situation.  I don't want to put the money into any sort of significant panel upgrade at this time, but I could see swapping out the unit for an integrated nav/com (something like a kx-155 would be fine) and dedicated DME, with the idea that it would become my secondary nav/com in a few years when I do the ADS-B upgrade (at which point some sort of WAAS GPS/nav/com will probably end up being my primary since I'll need a GPS upgrade anyway.)

[LANCECASPER]

There are a lot of these (KNS80) in good shape for sale - it's an easy, cheap swap until you decide what you eventually want to do.

[Jerry 5TJ]

Wow, what a great range of options you have!  

If I were in your position: I'd buy a couple of cheap KNS80s off eBay and use them as parts donors to keep one going.  Disclosure: I'm a retired RF EE with knowledge & test gear to do so.   Paying shop rates to do that would get expensive fast.  

Or you could mount an Aera 560 or 660 or 796 on the yoke and use it for enroute navigation, file /G (illegal but likely safe) and off you go.   

Or install a BNC connector so that if your unreliable comm radio flakes out you can connect your handheld VHF radio to an external antenna.  That will work just fine.

Or rip out everything now and put in one reliable GTN650 which will become your #2 unit sometime in the bright future.  Who says you need dual Nav/com?  That's 1960s era lore; the gear is far more reliable now.  Should it happen to fail you can fly an approach just fine using your iPad / Foreflight in an emergency.   (If you don't believe me hire a CFII and go try it)

Or tell your kids they're going to inherit your fascinating log books (and perhaps little else) & put in a whole new panel.  $100K would cover it.  Ok, $125K.

Have fun!

 

 

 

 

 

 

 

 

 

 

[ArtVandelay]

I think it overheats, a CB solution would be to channel cooling air onto the unit.

Try running a hose from the foot well air vent and see if that fixes the problem, if it does you can install a fan.

[carusoam]

Welcome aboard JC,

I vote no on the /G recommendation...  Somebody might ask to see that your database is updated...

The KNS80 was the coolest way to navigate via VORs until the GPS became accepted.  Then it became less and less desireable as WAAS GPS approaches became more available...

Sounds like you have a loose connection or a heat problem.  Have you tried to remove and reseat the unit?  Often, radios have a tendency to get dirty connections.  An electronics spray cleaner might be helpful.

Old WAAS Garmin radios are flooding into the market with all the GTNs and Avidynes getting installed.  There must be an equal number of KNS80s hitting the EBAY these days.

Best regards,

-a-

[carqwik]

I remember when the KNS-80 was the rage...never figured out to fly a parallel course with one of those but....  The GPS boxes are way more capable and powerful than the KNS-80.  Get a non-WAAS unit for now or splurge for a WAAS-unit and at least you are partly on the way to ADS-B compliance.

[Alan Fox]

I have probably 4 of these , 250 each , less than a repair...

[Pitchristian]

John , I just redid the panel in my grumman cougar and pulled out the kns80.its just sitting in my hangar was working fine. I will take something less than you can get off eBay if youre interested. Pm me or email pitchristian@yahoo.

Christian smith 

[pinerunner]

Mine went bad and my avionic guy found one and replaced in for just under $1000. I forget the exact price. They're old and hard to get parts I guess. I'm holding out for a GTN 650. I like my KNS80. They were the sweetest thing going back in the 90's. I still like that it has DME incorporated but I imagine once I get GPS I'll probably stop using it. For as long as they're still around they're still nice for VFR. But compared to cheap VFR GPS which you can get on your IPad?... 

[gsxrpilot]

Damn! I've got one still in the panel and working fine. It will come out as soon as I get a day to get it done. But there are lot's ahead of me for sale.

[johncuyle]

Thanks everyone.  I pulled mine out and re-seated it once without it improving things.  It's not an overheating issue (though it might be a heat damage issue, the panel is all original including lack of an avionics fan) as it exhibits the behavior even cold (got up very early a couple days to get to the airport by dawn so that I could cycle the power on when I knew it was cold <60 degrees F).  I've got some contact cleaner and will give cleaning the contacts a try.  If that doesn't work, I'll probably want to pick up a spare from someone here and hope it's the unit and not the rack/connector.  I like the unit itself (VOR/DME is about as easy to use a nav tool as exists) so I'm not in a huge hurry to upgrade.  If cost weren't an object I probably would take Jerry's advice and yank the entire stack in favor of a single GTN 650.  It'd probably take enough mass out of the panel I could net a useful load increase even after the nice engine monitor that's first on my want list and the intercooler that's second ;).

[Mark89114]

Buy about 5 of them and tie them all together and then go buy a boat and use them as anchors.

 

[LANCECASPER]

20 hours ago, johncuyle said:

Thanks everyone.  I pulled mine out and re-seated it once without it improving things.  It's not an overheating issue (though it might be a heat damage issue, the panel is all original including lack of an avionics fan) as it exhibits the behavior even cold (got up very early a couple days to get to the airport by dawn so that I could cycle the power on when I knew it was cold <60 degrees F).  I've got some contact cleaner and will give cleaning the contacts a try.  If that doesn't work, I'll probably want to pick up a spare from someone here and hope it's the unit and not the rack/connector.  I like the unit itself (VOR/DME is about as easy to use a nav tool as exists) so I'm not in a huge hurry to upgrade.  If cost weren't an object I probably would take Jerry's advice and yank the entire stack in favor of a single GTN 650.  It'd probably take enough mass out of the panel I could net a useful load increase even after the nice engine monitor that's first on my want list and the intercooler that's second ;).

Buy one from Alan for $250 - he's the used avionics guru on here. 

 

17 hours ago, Mark89114 said:

Buy about 5 of them and tie them all together and then go buy a boat and use them as anchors.

 

I don't agree. Having a working KNS-80 in the panel at least allows you to file /R and you can use a capable handheld to make things easier. A newer navigator looks nice but won't get you there 1 knot faster.

[Bob_Belville]

1 hour ago, daver328 said:

You have to put in brand new left and right panels, a new GTN-750, a new GTN-650 underneath it, a new ADS-B Transponder, a new JPI EDM -930 primary instrument monitor, a new audio panel ... and all new duel Aspen glass ... with a new Garmin G5 as a standby ...

;-) 

Listen to this guy, he's a pilot, that's deity to earth bound creatures.

[Danb]

Hey Bob how'd Maine go? Hi Nancy

[Fredrich Clarkson]

Does anyone still have one of these?  I need to replace my KNS 80.  The glideslope has stopped working.  No one will work on them anymore.  I will be replacing it with a GTN750 or 650, but the backlog is about 6 months!  I need to do an IPC and you need at least one precision approach. 

[PeteMc]

15 minutes ago, Fredrich Clarkson said:

Does anyone still have one of these?  I need to replace my KNS 80

I've got the whole system.  It was working when I pulled it, but could take to get check.

 

[carusoam]

On 1/28/2022 at 10:25 AM, Fredrich Clarkson said:

Does anyone still have one of these?  I need to replace my KNS 80.  The glideslope has stopped working.  No one will work on them anymore.  I will be replacing it with a GTN750 or 650, but the backlog is about 6 months!  I need to do an IPC and you need at least one precision approach. 

See if @Alan Fox has something for this…

-a-

[rbp]

I have a non-WAAS GNS530 with antenna, rack, and backplate for $3800. my primary nav/com/gps for the past 20 years, in fine shape, for $3800. email 54x@pasker.net 

[Biblebath]

I am hoping someone can help me. I have a late model M20B with a KNS 80 for navigation. The RNAV and the DME work fine but when I change over to VOR the CDI only reverse senses, like I'm flying a back course. I have spent about 2.5 hours with my CFII to find out what is going on and we both are unsure why it is this way. Any help would be great or if you know some one I will be happy to reach out.

[KSMooniac]

Welcome.  I would contact Bevan Aviation in Wichita as I believe they still work on these.