lights in the KX170B and KX175 inop

reyobs1950

My Warrior's lights in the two nav/COMs will not come on. Both the Com and Nav work fine, just no night lights coming on. Checked the old pop out fuzes, nothing popped. Instrument lights come up fine.

So, I don't know exactly where the lights are located inside the two nav/coms, but with both out I suspect it is not an inside the box issue. Something must be disconnected/shorting out.

Any suggestion in fixing?

Tom_Jax

Do any of your avionics back lights work? If no, I would look at the radio lights rheostat. If some work, and others not, look at the wiring. Can be a hassle getting to the dimmer below the stack without removing some of the equipment. If your shop has a bench power supply and the schematic you can put power on the pin on the radio and see if the boxes are working.

reyobs1950

Tom Jackson, hey you are just up the road from me, I am in Charlottesville!

The instrument lights seem to be fine. The only issue is apparently the lights in the two radios. I will have to cover up the plane to block out all the light to tell if the compass light is working.

Tom_Jax

I have a KX170B that I removed from my Arrow, happy to work something out to get it to you. Nav and Com both worked when removed. Make an offer, I'm happy to fly to CHO and drop it off.

n36601

Reyobs:

My Warrior's KX-170B internal lighrs are energized by rotating the thumbwheel. Not the thumbwheel that energizes the panel lights, the other thumbwheel. Most likely the dimmer circuit for that thumbwheel has failed. Hopefully, it's not the thumbwheel rheostat or switch, as that component is very hard to source. Replacing the transistor that serves that circuit may fix your problem. The transistor is very easy to source.

Are your position lights working properly?

VFRs,