avionics trouble

[tmbg]

I have a KNS-80 in my cherokee, and I just recently started my instrument training. Sunday morning I flew with my instructor at 8am (an unholy hour which my plane and I rarely see ), and the KNS-80 was Tango Uniform! Pressing the VOR button (which normally takes it out of RNAV mode and puts it in VOR mode or cycles CDI sensitivity) was accomplishing the same function as pressing the DATA button. Weird. Further, the CDI had needles centered and both off flags, despite being tuned to a valid VOR which I could Ident, and DME data was showing correctly.


Sunday evening I flew again alone, and the KNS-80 was working perfectly! I flew again last night with my instructor, and again, it was working perfectly.


I have a couple other problems with the panel... my DG is pretty well shot, it precesses about 30 degrees every 15 minutes, and the spring in the adjustment knob is gone, so if I'm not consciously pulling it all the way out every time I set it, it'll freeze. Also, my second nav is a Narco NAV-121 which I put in last fall, and I have no ident audio out of it, and last night my instructor was tuning it and the center frequency select knob started spinning freely. Hopefully it's just a setscrew, I didn't look closely at it yet, but my avionics guy said that it's common for them to strip the nylon gears inside

Also, my compass light is out, and it's not the bulb.

SO, plane's in the shop getting the DG replaced, he's gonna try to get the compass light working and look at the NAV2, and pull it if necessary to send it to Narco for repair. As for the KNS-80, his suggestion was just to fly it til it breaks again, other two options are to send it off for a hot/cold test, and repair if necessary, or replace that plus one of my slim comms with a 430, to the tune of $11k

[Spike]

The 430 is a fantastic unit. Ive had one in the Cessna for about 3 years now and it really is the cats meow.

[tmbg]

yea, I know it's a really great machine. I trained in alaruses, and they had 430s in them. I'd love to own one, but it's really a question of money. I'd have to get a loan to do it, and I'm not really in a position to do that right now


Since the primary problem is losing my NAV1 AND my DME, maybe I'll get an apollo SL50 or SL60. I can get a 50 for about 1k or a 60 for 1600. That'd give me non-moving-map GPS, but then I'd really also need another nav radio with a glideslope :/

[Spike]

Sounds like you might be getting stretched a bit thin with the project and the rating. Maybe pick one, focus on it, and then return to the other?

John

[cjensen]

I agree with Spike here. Get the IFR rating done! That's one rating that is SO elusive for many people, and if you start/stop/start/stop, you'll never get it. I see it all the time here at our flight school.

The RV will always be there...get the rating if there is a choice that needs to be made. One month, and it's over with! Then back to the RV...

[tmbg]

I'm definitely focusing on the rating, but I don't have an additional $11,000 to spend on the rating OR the RV right now!

I already had the DG replaced and the NAV2 pulled for overhaul. I'm pretty sure I'm gonna snag a yellowtagged KNS-80 and swap them, then sell mine as-is/repairable.

[cjensen]

That sounds like a smart plan to me! I had a KNS-80 in my 140, and while a bit dated, it worked great! Besides, a good handheld is every bit as good as a 430...just can't shoot the approaches with one (legally)!

[BrickPilot]

I have a KNS-80 in my cherokee, and I just recently started my instrument training. Sunday morning I flew with my instructor at 8am (an unholy hour which my plane and I rarely see ), and the KNS-80 was Tango Uniform! Pressing the VOR button (which normally takes it out of RNAV mode and puts it in VOR mode or cycles CDI sensitivity) was accomplishing the same function as pressing the DATA button. Weird. Further, the CDI had needles centered and both off flags, despite being tuned to a valid VOR which I could Ident, and DME data was showing correctly.


Sunday evening I flew again alone, and the KNS-80 was working perfectly! I flew again last night with my instructor, and again, it was working perfectly.

Could it possibly be condensation inside the unit? Early in the morning - dew forming inside? While it's out, make sure it's cleaned thoroughly - dust and grime could help cause shorts as well. Couldn't hurt.

[pilot2512]

As a former ga avionics bench tech( now w/ the airlines) my memory seems to recall a service bulletin that affected these unit for this problem. board to board connections have been a problem. Have your avionics shop check your mod status.