DME Schematics questions
 

I was looking thru the DME schematics and trying to figure everything out. Has anyone else looked at them and figured them out?

Does anything come out of the test pin (pin 12) on the DME. It looks like it goes to a serial output pin on the 8051.

Where does the CASIS light signal come from? Pin 11 says it goes to the tach but it comes from a pin on the injector solenoid driver. The only input to the driver looks like a signal from the 8051 that must be the injector on time command, the PWM signal. The injector driver couldn't figure all that out on its own could it? Pin 21 also goes to the tach but it looks like the tach signal.

Someone said the only custom chip in the DME was the amp for the reference mark/speed sensor. I can't find anything on the injector solenoid driver either. Anyone have a part number on it or a similar part. I can only find one other part that has the PNP transistor to shunt the back EMF of the coil but t has a very different pinout.

These aren't urgent questions I was just killing time.

Does someone have a link to a DME schematic? I am building something that really would be easier with an idea of what is inside the box.

Wayne

See FR Wilke's web site. Click on "Download Schematics" on the left side of the page at the bottom of the blue list.

Wow! Wilke's website has some amazing info. Does anyone know if he reverse engineered all of the info himself?

My project either just easier or it just got larger. It will take a little bit to digest all of it.


Wayne

Wayne

I'll bite What are you trying to do? I'm just a EE curious how Bobby Bosch solved all the electrical challenges and how to fix it when it breaks.

I hate to think how long it took to draw that schematic. I'm surprised it is available for free.

For those of you curious about "the DME " I would suggest
getting a copy of the Volkswagen Of America, Inc Corporate Service Training manual WSP-490-521-00 "DME Testing Plan"
published in 1983 to educate Porsche Techs on the how too's.
This is a 23 page manual that contained the Introductory Service
Training Information.
Anyone wishing a Reprint email me privately and I,ll see what I can do for a small fee to cover costs.

Keith -Wichita, Kansas Regional Membership Chairman