W116, Body and Interior Specific Aid

The radio in my 84' 300d is a Becker Grand Prix Electronic and when I start the vehicle the radio comes on, then cut in and out every 2 seconds consistently. Now if I turn the radio power button off, then turn it back on a couple seconds later it works fine. I want to stay original, any advise? Thanks.

I have been having intermittent hard starting with the engine warmed up. The problem only happens after the engine has warmed up to 80-90 C. The car has new glow plugs decent compression (300+ average)and starts right away when it's cold (below freezing).
The car always starts eventually but I have to crank for awhile 10-30 seconds. Same problem when running on diesel or veg and with oil just changed or ready to be changed. I don't think that I'm getting air in the lines and again it's intermittent so sometimes it starts right up when warm?

My heat has stopped working just in time for the cold weather! The temperature control unit works fine except for the complete lack of heat (the buttons all seem to do what they're supposed to). The heat gauge on the dash shows that the engine is getting hot, but none of the temp. control settings (defrost, bi-level, etc.) make hot air blow. The air coming out of the system is the outside temp.-frigid! I recently rebuilt the vacuum pump after the diaphram tore and a little oil got in the lines. But this sounds like an electrical problem, no?

I recently got the Mercedes factory HVAC manual, but I don't know where to start with this problem. I have the vacuum and wiring diagrams and now have a rough idea of how the system works (it's complicated!).