I have a BK2000 that has a light matrix issue. The first 4 columns light exactly how they should in single light test. When I get to the second half of the matrix, all 4 lights in the corresponding columns light up when I test a single light. So for the entire second half of the light test, there will be 4 lights on for each lamp. The lights flash just like they should. Nothing is locked on, just 4 lights flashing for each second half of the light test.
I have even disconnected the connectors for the strobe and return off the cpu board and checked the transistors withe a logic probe. The transistors are not functioning like the first 4 with all wires disconnecting. It is acting like something in the cpu board is telling it to act differently.
What I have changed - all new tip 42 transistors, new pre driver transistors, new 7408 chip for the second half of the matrix, and a new 6821 PIA.