replace a kx 170b with kx155

Jon Gunther

Jon Gunther

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Jon Gunther
Hello, can anyone tell me what would be required to replace a kx 170b with a kx155. My glideslope indicator quit working. Im not sure which cdi I have but I know it has a built in glideslope computer. I have been seeing several kx 155's come up for sale and was trying to decided if it was worth it to make the swap or just peruse a kn-75 computer and a new cdi.

Thanks for your help
 
You KX170 indicator is incompatible with a KX155. A KX165 would talk to your existing indicator.
 
I would be replacing both. From my research the problem is with the indicator. The VOR/LOC work fine but the Glideslope is inop
 
New tray, new indicator, new wiring between. Is your plane 14V or 28V? The KX170 is a 14V unit that can be fitted with a 28V converter. The KX155 has different models based on the voltage (if I recall properly). Most of the newer radios can run on either.
 
why replace a 40 year old radio with a thirty year old radio? the 155 although a great radio has seen its day. displays are not available as are a lot of other parts in the radio. if its time, buy a new radio or at least a serviceable unit like a sl-30.
 
unsafervguy said:
why replace a 40 year old radio with a thirty year old radio? the 155 although a great radio has seen its day. displays are not available as are a lot of other parts in the radio. if its time, buy a new radio or at least a serviceable unit like a sl-30.
Click to expand...
Because the 40 year old radio is built like a brick s#!+house (except for the damned nylon gears) and the 35 year old radio is built out of toothpicks and tissue paper.

Jim
 
Jon Gunther said:
Hello, can anyone tell me what would be required to replace a kx 170b with a kx155. My glideslope indicator quit working. Im not sure which cdi I have but I know it has a built in glideslope computer. I have been seeing several kx 155's come up for sale and was trying to decided if it was worth it to make the swap or just peruse a kn-75 computer and a new cdi.

Thanks for your help
Click to expand...
The KX 170B and the KX 155 [14V] are identical w.r.t. operation.
Your CDI will work on the KX 155 and even has a pin to select which voltage input.
 
The only advantages to the KX155: the last 40 comb channels and flip flop. As Jim points out, the KX170B is pretty bulletproof.

On the other hand, the SL-30 is a real nice nav com though you'll have to get a new indicator.
 
unsafervguy said:
why replace a 40 year old radio with a thirty year old radio? the 155 although a great radio has seen its day. displays are not available as are a lot of other parts in the radio. if its time, buy a new radio or at least a serviceable unit like a sl-30.
Click to expand...
BoB?
 
A little update on the problem I was having. We decided to try swapping the radio boxes first. We have the KX-170b and a Mac-1700, since they are interchangeable we swapped them. On the next ILS test we did, we found that the glideslope did work as expected however, the localizer is 5 degrees off. We verified this by having the second radio tuned to the localizer as well. We have also performed several duel VOR tests on different stations and have the same 5 degree difference. The CDI that is in question is a KI-214, our next step in trying to get this fixed is to take it to the avionics shop and see if they can calibrate the CDI. Crossing our fingers.
 
I have one of each, along with the rest of my old equipment going up for sale soon. Audio panel, transponder, etc. King stuff
 
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