Where to buy Avionics Repair Parts

I recently purchased a KLN-90b and one of the outer knobs was difficult to turn. I ultimately pulled the face plate and fortunately it looks like some clean up and a new plastic part should fix it.

I was looking for a recommendation on where to buy Avionics repair parts, either new or surplus/used.

Thanks for any assistance you can provide.

Larry

parts

Try Rocky mountain avionics in Kalispell Montana, Glacier park airport.