Hey All. I have been a member for some time, but haven't really been "active". I have a really good '72 Cherokee 140 that I used to take my lessons and get my license. Plane is in excellent condition, and has many features added to it. My dilemma, is that I have an old MK16 radio in in, and I want to take it out to install a working 12E that I have on the shelf. The previous owner of the airplane was a stickler for keeping all documentation pertaining to the installed equipment, other than an installed RST-501 Audio Panel. I was wondering if anybody out there happens to have a set of schematics or a wiring installation diagram that I might acquire somehow. I looked on their website, and the farthest back they go is a 502, which is significantly different than the 501. The 501 works well, and due to much medical maintenance to myself and my wife, there isn't any AMU's to upgrade this year. Plus, insurance and the annual are coming due in the next couple of months. My MK16 is on the fritz, so I have no backup radio, but I have a good 12E on the shelf, so I would love to get it installed. Thanks for looking.