I have an 8050D radar. A bit oldish, but a solid performer. Issue - it worked fine yesterday, but today the tuning bars don't show any tune indication and the image is very weak and only shows in the .25 and .50 rranges. Seems the tuning circuit/ function has quit or gone out of range. Any ideas on where to look for adjustment of locating the source of the problem. I like this old simple set. It is a "tank".