Perhaps those are the Factory Updated Parts that are mentioned in the Service Bulletins or someone was being proavtive about have the components on hand in case it went poof - Chris
Ha ha, if only I was so lucky!!! Actually this design predated the venerable 458.
These parts were in a box that was sent along. I think the owner just got one of everything when a channel went. One of the diodes is unsoldered. I may be using some of these. I did test the 4 outputs and one each of the NPN and PNP is totally shorted - all pins. That's as far as I got last night.