Fairchild 670 Lateral/Vertical Matrixing Info

I'm building a PM670 and want to incorporate the Lateral/Vertical matrixing scheme included in the grandaddy original.  The Fairchild 670 manual and schematics I have don't include the matrixing circuitry.  Does anybody have any info on it?  I've searched the forum high and low (and in between) but haven't found anything substantive.

Thanks,

---Joe

Joe, look closely at the schematic.  It's there in the transformer switching on the input secondaries, etc.  Unless you mean something else. 

You might want to read through the http://www.groupdiy.com/index.php?topic=29056[/url mod thread.

If you're hacking the Edcors for this, you can simply split the center tap to two (thus fully exposing the two primaries). Some minor desoldering surgery is needed for this (thanks to emrr's tip we know this).

If you're using some other transformers, chances are the primaries are already fully accessible.

Other than that it's just a lot of extra wire, and to simplify things up you might wanna think about using a little utility PCB(or vero board) with relays. (I know I will)

Thanks for the responses. This will get me on my way.

---Joe

Does anyone know about the fairchild 653, I am looking for the schematic. There is a 663  posted on GDIY, but it is not the same unit.
any help would be great.

Thanks, Tony