I have a buddy with a PRC113 and wanted to know about the dial backlight, what they are, LED or incandescent, type of bulb, or if there is a bulb at all involved. He also has a low squeal or tone in the audio and wondered if that was a common problem and common fix. Please tell me it is so I can tell him and he can fix it and not me fix it. Charlie, W4MEC in NC