If your are in the U.S You may also try Peninsula Avionics:

14229 SW 127 Street
Miami, FL 33186
305-238-6550

I'm pretty that's who worked on my radio a few years ago. But be ready for sticker shock. My Dittel wouldn't turn on. I sent it out and was told it was the internal battery, which didn't make much sense to me. But what do I know. Well over $300 later it had a new battery, bench tested and checked out and still didn't work. It turned out to be a loose wire on the fuse holder.