69 Electrics

[JPM]

I have a question about the Bosch Tach adapter p/n 0 227 990 001 wired with the Bosch CDI on my 69 911. Wiring diagram SL 33 refers to it as Switching SCR, for the 69 Model and SL 35 calls it the Intermediate Unit, for the 70 Model. In a picture of the electrics it is called the RPM Sensor.

From what I have read in Pelican forums and in the PET catalogue, it is referred to as a Ballast Resistor(3 pin silver can). Some have opened it up to take a look and make measurements and it bears no resemblance to what I think of is an SCR(semi-conductor controlled rectifier). Is the part misidentified in the SL 33 factory manual?

My connections do not match the wiring diagram either. I have the high voltage lead from the CDI going to one pin, a second pin feeds the ignition coil transformer terminal A and the third pin feeds the Tach, I guess. If it was an SCR where is the controlling pulse coming from?

Another oddity, I have what looks like a radio noise suppressor on the left. It is a 2 pin cylinder (2200mF), one pin gets switched power and the second ground pin goes to the CDI ground terminal.

I might add that it all seems to work, so what am I worrying about! Just trying to make sense of it all.

[patz]

Ingo is the resident CDI expert. 3.6@cox.net

[kav]

I had similar questions about my 69' T on the 'other' site.

Engine bay wiring help.

Hopefully this helps.

-Kav.

[JPM]

Thanks for the inputs guys.
I forgot to add that the 69 911T is the orphan of the factory wiring diagrams, as lamented in several posts from the very missed Warren Hall and Grady Clay. Prospero Garage confirmed that he doesn't have one for the 69T. So the best we can do is using SL 33 for 911E/S as guidance,

Kav, your setup looks familiiar including #4 hanging brown wire. My yellow wire is connected to another yellow wire through the WECO connector(I believe it goes to the starter solenoid). I really enjoy your videos and salute your temerity for taking on the restoration of your 911. I am currently planning to relocate my fuel pump to the front cross member.

JP