Hmm,
Definately NO continuity between pin 12 Z26 and pin 15 U5. Might be an error in schematics as the track from pin 15 u5 pin 10 Z12.
Marty,
Just checked on two (2) spare boards I have and Pin 15 of U5 goes to Pin 12 of Z26 on both. One was a System 80a and the other system 80b. This is as per the schematic. You sure your looking at the correct ICs. U5 is the middle of the three 40 pin 6532s abd Z26 is the bottom right hand IC.
