Transistorized Ignition - how to measure dwell?

[ptspringer]

I'm trying to tune my 1972 350SL (4.5) which has transistorized ignition. As I understand it, the mechanical points inside the distributor switch a small voltage to the transistor "switchgear", which drives a much larger current to into the primary circuit of the coil. I'm afraid if I hook up my dwell meter incorrectly, I could put too much voltage into the input of the transistor unit (why is it called a switchgear?) and burn it out. I have an old-time dwell meter that has a setting on it for transistorized ignition. How do I hook it up? (across the coil leads, from one of the leads to ground, which lead)

Thank you,

Paul

[Arthur Dalton]

http://www.peachparts.com/shopforum/vintage-mercedes-forum/184778-setting-dwell-transistorized-ignition.html#post1474349

[stevebfl]

It ain't called a switchgear its called a switching unit and they call it that because it switches the coil on and off. There were three versions of the transistor ignition used and the electrical hook -up varied. The most commonly usefull point was a round hollow connector mounted to a two point buss connector. It can be found by following the green points wire from the dist down to the front of the left fender behind the headlight. The wire is screwed to one terminal of the buss and the connection point is mounted there also.

[ptspringer]

I'll finish tuneup today.

Paul