more like this ?

Blue are the U20 inputs and Red outputs
pin 9 Gnd J210-1,3
pin 10 12V J210-6,7

wpc89-u20-in-out.JPG

Made some improvements

wpc89connect75pct.jpg

Column drives, matrix rows, enable and direct inputs are defined by color.
Now everyone can repair the switch input of the wpc'89 board.
Picture will be ready in a few weeks.

The big picture, I checked it several times for errors but looks OK now.

I think you are right about that, although I can read schematics, these kind of pictures help me as an addition next to the schematics.
Chris H., You are free to publish it on PinWiki.
If someone has suggestions or additions, please tell me.

WPC89-CPU-board-200dpi.jpg

Thank you .
This picture is automatically compressed with uploading, the original is even better but also 3 times bigger file.
Will have to work on my website and post it there somewhere in the future.

Send and received, great !

Made some final changes, U14 corrected from LS37 to LS374 and changed text Q1 section into "coin acpt enable".
I will upload it to Chris H. so it can be found on the PinWiki when implemented.

To complete this picture, here is the diagram of the switch inputs with the corresponding colors.
In the pinball-manuals this picture is not entirely error-free, this one is clear and simple redrawn.

enjoy

wpc89-cpu-switch 2 IEC-639.jpg

Thanks Ingo, really appreciate you find this an awsome pic.,

The list with errors goes on and on at this page in the manual.
The individual comparators are so close drawn to each other, that it looks like all pin3 (+12V) and pin12 (GND) are connected to each other.
Also, J205 has only 5 of 12 pins correct in the manual, better skip this page
Well, as always, don't trust the manual and verify twice.
I'm sure these pictures will help a lot of people. Lot of time has spend in verifying schematics and board, buzzing with meter and scope, but even then a mistake is easy made.

Next picture will be an easy one I think, a balltrough PCB or so, and will get it's own topic instead of hijacking this one (sorry Demetris)

Nice work, Ingo but you need a lot of time and patience.

I think all the pin 3 + 12 of LM339's shouldn't have been drawn in the picture at all, in the schematic-manual the power pin connections of the IC's are already mentioned in the upper right corner.