The modified hybrid board is designed to operate in three different modes. All analog outputs share a commone trace. The second mode in which the shift in is sent to all Vikings at once and the analog outputs are sent through different traces. The analog outputs of I and II share a trace and the analog outputs of III and IV share a trace. Here is a color coded postscript file of the modified hybrid board .
Jumpers connect different pins in order to switch between the three modes.
The following section describes which pins need to be connected for the different modes of operation. The original hybrid had one connector on it. An Erni connector. The modified hybrid has a ten pin connector added to it to handle the additional analog output lines. Bias Lines Other Modifications Traces and pads to three digital inputs to the Vikings were erased since they are no longer used.