Hexbus TI-99/4a Adapter Schematic needed

[TI998owner]

Hi Group,

I am interested in a Schematic of the prototype TI-99/4a Hexbus

Interface, also I am interested in the logics replacement chips numbers

That would replace the PAL chip used in the original design.

, Michael Becker designed a working replacement TI-99/4a Hexbus

Adapter, and built a couple of them many years ago. That schematic

Is one I am interested in also.

Thanks I. Advance for any help

TI998owner Lee