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Odd problems with nav of a 155A


Niko182

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For the time being I have 2 KX155A nav Comms in my aircraft. My issue seems to revolve around the HSI , but id put money on it that its a connection issue. When I tune localizer or ILS into the nav, it works perfectly. When i input a VOR into it, I get a flag. Ive tried it with a VOT check and same thing. I dont think somethings wrong with the kx155a, since when the frequency is in and set it to show the radials on screen, theyre pretty accurate. I tried switching the #2 and  #1 nav and it made no difference. 

 

I thought id ask here. Its not worthwhile thorwing money at it. The plane goes in for avionics on the 4th of january, and everything is getting ripped out. Literally nothing in the panel is staying except for the CBs and the panel lights. And i can fly light IFR just fine with a spare nav.

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1 minute ago, carusoam said:

Niko,

Can you swap your KX155s to demonstrate the radio is not the problem?
use the electronics cleaner on the connection while you are in there...

Best regards,

-a-

Already done

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 When tuned to a localizer, the system is tracking a single, distinct,  radio beam(forget the GS at this point). When tuned to a VOR, the system now needs to "resolve" which of the 360 radio beams to track. Unless the radio knows what radial to track, it will drop a flag. May I assume the HSI is a KI 525A?

 By all means try to swap the radios and check it, I'm curious what you will find with this one. Do you have NAV/GPS switching to that HSI, maybe an old MD 41?

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What does the nav audio sound like? If you can’t hear it neither can the decoder.

When I used to work for Raytheon Data Systems, the engineering department said to use a dollar bill to clean edge connectors. I have found their method to work the best. Just fold the bill over the edge, pinch it with your fingers and slide it back and forth. If there is not enough room to fold it over, just rub it on the fingers. It will clean and polish the gold plating without removing it.

And for aviation use, a hundred dollar bill will always work better...

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I had to refresh my memory, but the difference between a 155 and 165 is that the 155 requires an external resolver converter, maybe a KN 72.  So, that may be your culprit.  Look for a narrow rectangular box, standing on edge.  May be mounted in back....

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1 hour ago, Bob Weber said:

 When tuned to a localizer, the system is tracking a single, distinct,  radio beam(forget the GS at this point). When tuned to a VOR, the system now needs to "resolve" which of the 360 radio beams to track. Unless the radio knows what radial to track, it will drop a flag. May I assume the HSI is a KI 525A?

 By all means try to swap the radios and check it, I'm curious what you will find with this one. Do you have NAV/GPS switching to that HSI, maybe an old MD 41?

This is a Mooney Eagle so it's probably an STEC ST-180 HSI. (http://vonesh.com/pdf_files/HSI.pdf)

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On 11/1/2019 at 5:18 PM, carusoam said:

Got it, after I posted the extraneous question... :)

Looks like chasing the wire to the HSI is next...

Got the wiring pin outs for the HSI?

Best regards,

-a-

Did you get the HSI Pinouts?  If not, which one do you have?  KI525A?  NSD360? Email me if you need them still and I will see what I can do my friend!!!

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On 11/3/2019 at 8:19 AM, N201MKTurbo said:

What does the nav audio sound like? If you can’t hear it neither can the decoder.

When I used to work for Raytheon Data Systems, the engineering department said to use a dollar bill to clean edge connectors. I have found their method to work the best. Just fold the bill over the edge, pinch it with your fingers and slide it back and forth. If there is not enough room to fold it over, just rub it on the fingers. It will clean and polish the gold plating without removing it.

And for aviation use, a hundred dollar bill will always work better...

 

 

I routinely used a green tag form soaked in IPA. Today I preach Stabilant 22, I will be trying the hundred dollar bill and report back!

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