Hey all, I'm back with a head-scratcher, and luckily not a tech issue this time, just something... strange.
Since I installed it, my 6000's Program insert hasn't worked at all. There's a mod to add one later in the signal path, but it seemed weird that you'd need to add one at all. It's taken literally a year and a half to realize why: The only mix buss cards in this console are two 26 cards. There aren't even slots in the master section for another two cards, their usual spots are unpopulated. Moreover, C1 and C2 on the buss inputs have also been removed, so theoretically the cards shouldn't be getting any input. And yes, the bus compressor all three busses work fine, as do their inserts as far as I know.
Right now, I'm operating on the assumption that a previous owner modded this console so that all three busses went right from the 688 and into the pre-VCA insert returns, in some attempt to improve sound quality by removing the shared buss cards and avoiding the transistors on the input stage. Does anyone have experience with any mod like this? And if so, would it be possible to revert some of these modifications and bring all the buss inputs into the proper input on the card instead? Would there be any reason to do this besides trying to get the console to sound closer to stock?
Edit:
So, after tracing mod wires and consulting the spotty schematics I have, it seems like my console's service manual is the real issue here. Not only is it missing a ton of schematics for the 688V and some of the master section cards, but it looks like it was put together with an earlier(?) revision of the 6000E in mind, and nowhere does it state that the 26 cards are supposed to be fed directly by the stereo outs of the 688. You live you learn, I guess.
