ISO used Nav/Com radio

[201Steve]

I have a KX170b installed as navcom2 that I’m having a little trouble with. It is barely useable for communication. If I dial in the ATIS, I can barely hear it until I’m like 2 miles from the field, can’t talk on it without getting feedback in the ears. The VOR indicator that its hooked to seems to work pretty well so it’s not totally useless... but in the market to see what folks might have laying around they part with?

[Andy95W]

That sounds more like an antenna problem to me.

[carusoam]

Cleaning antenna connections and grounds may work wonders...

Might be this vacuum tube things wearing out...

There is a resource for getting those fixed..

or find that shelf full upside down used radios that was for sale around here...

Search from @Alan Fox to find the inventory...

PP thoughts only, not a radio salesman...

best regards,

-a-

[EricJ]

Definitely worth checking connectors, cables, antennas, etc., to see if it can be brought back easily.  You'll want to check a lot of that stuff since it may affect any replacement radio, too, anyway.  Elsewise used KX170s are not expensive, and if you don't mind spending a bit more the TKM slide-in replacements are very good and much more modern (I have one).   

[201Steve]

Thanks for the feedback! Will probably be a good first project on the panel to get familiarized with the innards.

[201Steve]

On 6/25/2019 at 9:30 PM, EricJ said:

Definitely worth checking connectors, cables, antennas, etc., to see if it can be brought back easily.  You'll want to check a lot of that stuff since it may affect any replacement radio, too, anyway.  Elsewise used KX170s are not expensive, and if you don't mind spending a bit more the TKM slide-in replacements are very good and much more modern (I have one).   

Seems like spending $3,500 on a TKM, I'd almost rather find a used 430, spend an extra $1,000 to also have another GPS. I don't understand why basic radios are still so expensive.

[KSMooniac]

You can likely still get a 170B repaired for modest cost...Might be worth it to extend the life a bit before shelling out more money for a modern replacement. I'd rather do that in conjunction with a well-planned (and scheduled) panel update versus needing to get something installed "right now," especially considering the current avionics shop load with the ADS-B rush.

But certainly start with antenna connections!

Sent from my LG-US996 using Tapatalk

[EricJ]

6 hours ago, 201Steve said:

Seems like spending $3,500 on a TKM, I'd almost rather find a used 430, spend an extra $1,000 to also have another GPS. I don't understand why basic radios are still so expensive.

Look for used of either.   Since a TKM is a slide-in replacement, there would be no installation costs since it requires no changes and you can legally do it yourself per the FARs.   Likewise if you find a servicable KX170.

 

[jaylw314]

9 minutes ago, EricJ said:

Look for used of either.   Since a TKM is a slide-in replacement, there would be no installation costs since it requires no changes and you can legally do it yourself per the FARs.   Likewise if you find a servicable KX170.

 

Are you sure about that?  I could understand reinstalling it if it got repaired in the shop, and even replacing it with an identical unit, but replacing it with a slide-in alternative under preventative maintenance?

It's splitting hairs, I know, and I imagine many A&P's would sign off on it without charging you anyway, but still...

[EricJ]

6 minutes ago, jaylw314 said:

Are you sure about that?  I could understand reinstalling it if it got repaired in the shop, and even replacing it with an identical unit, but replacing it with a slide-in alternative under preventative maintenance?

It's splitting hairs, I know, and I imagine many A&P's would sign off on it without charging you anyway, but still...

Doesn't need an A&P sign-off, because it does fall under preventative maintenance.   Maintenance record entered by the owner is sufficient.   The pertinent FAR is 43 Appendix A(c)(31):

(31) Removing and replacing self-contained, front instrument panel-mounted navigation and communication devices that employ tray-mounted connectors that connect the unit when the unit is installed into the instrument panel, (excluding automatic flight control systems, transponders, and microwave frequency distance measuring equipment (DME)). The approved unit must be designed to be readily and repeatedly removed and replaced, and pertinent instructions must be provided. Prior to the unit's intended use, and operational check must be performed in accordance with the applicable sections of part 91 of this chapter.

 

[jaylw314]

31 minutes ago, EricJ said:

Doesn't need an A&P sign-off, because it does fall under preventative maintenance.   Maintenance record entered by the owner is sufficient.   The pertinent FAR is 43 Appendix A(c)(31):

(31) Removing and replacing self-contained, front instrument panel-mounted navigation and communication devices that employ tray-mounted connectors that connect the unit when the unit is installed into the instrument panel, (excluding automatic flight control systems, transponders, and microwave frequency distance measuring equipment (DME)). The approved unit must be designed to be readily and repeatedly removed and replaced, and pertinent instructions must be provided. Prior to the unit's intended use, and operational check must be performed in accordance with the applicable sections of part 91 of this chapter.

 

It's the "removing and replacing" part that gets me.  That wording suggests it's intended to be the SAME unit that is removed and replaced, as opposed to if they had said "removing and installing."

Is there any clarification or written interpretation on stuff like this anywhere?

[EricJ]

Just now, jaylw314 said:

It's the "removing and replacing" part that gets me.  That wording suggests it's intended to be the SAME unit that is removed and replaced, as opposed to if they had said "removing and installing."

Is there any clarification or written interpretation on stuff like this anywhere?

I don't think it suggests anything other than you remove one tray-mounted box and replace it with another that meets the description in the paragraph.   There is nothing that says they have to be the same make/model or even same function.   Many people have replaced Garmin 530/430 units with Avidyne 540/440 units this way, too.

My IA was fine with it when I swapped the TKM in for a King unit and made my own maintenance entry, and he won't sign off owner maintenance, period.   He was fine with it because it only needed my signature.

I looked around a bit and couldn't find anything from the faa that speaks directly to this point, but there is this that sheds only a little more light on "preventive maintenance" and pretty much just says to use good judgement: 

https://www.faa.gov/regulations_policies/advisory_circulars/index.cfm/go/document.information/documentID/99859

[Yetti]

first step is to re rack it.   figure out the allen wrench size.  Turn it the correct way.  Remove it and replace it several times.   What this does is clean the connectors in the back of the radio.    This is also the first step in fixing an old IBM mainframe computer.

Edited June 28, 2019 by Yetti

[bob865]

LIke everyone said, re-rack it.  Be careful with the 170's.  There is a switch that if you turn the latch too much to remove will break.  If you haven't already visited kx170b.com yet, I recommend you do.  He explains how to remove the radio without damaging the wafer swtich.  Pluse he has a whole section on "weak" radios.  The quick summary of that section is, it's not the radio.  Last step, if you need a radio, throw a post in the for sale section with a Want To Buy (WTB) heading.  I did this when I was in need of a new KX170 a month or two ago and had two offers within hours.  Maybe those guys sold all of the radios, but that will get you more attention for finding a new radio than the avionics/panel section.