ZX8-CCB PCB Connections

The ZX8-CCB composite video converter for the ZX81 needs three input signals:
  Ground, +5VDC, and the video signal from PIN 16 of the ULA.

There are several differend version of ZX81 and TS1000 Printed Circuit Boards.
Here are two marked up photos of a USA ISSUE ONE ZX81.

The photo above just shows three possible PCB points you can get the signals from that you need for a ZX8-CCB.

 This marked up photo emphases how the signal point information can be derived from the shematic.