Vintage Cars: 1980 240D, neutral safety switch, shift linkage

Question
Having trouble with 'ignition starter'.  Turn the ignition, nothing happens?  We have a 'get around'..sometimes works.. shift from park all the way down to low repeatedly, then try ignition sometimes 'works':-)?

We have taken the car to a mechanic, and 'repaired' however normally after a few weeks, the ignition behaves the same way again?  Afraid to drive, don't want to get stuck!

Really love this car, I am the second generation owner and would love to maintain/restore like new.  It's my commuter car.

Answer
sounds like your neutral safety switch on the tranny.   Not to bad to replace. Is your mechanic familiar with MB's - if so he should know this is a common issue, pretty straight forward fix.  SOme folks try to adjust shift linkage when problem is switch

Also common - bad ground to body off battery

My bet - neutral safety switch..