Thanks for the suggestion, yeah , was thinking that it was probably caps, have seen that issue too often on motherboards built around that same time. Also really like that BASH Solution! Might be almost cheaper than having to have the two plate amps recapped by someone. I had thought about maybe selling them, as $ is a bit tight lately (wife got told her job's gone next week- merry xmas), but may need to shelve that idea for now . It's always something...
Update: Well, whatta yah know, turns out it was my wiring that was the issue, seems I'd forgotten that in order for the sub amp to get signal you actually need to use the jumpers to do exactly that! I had them connected from the amp to the amp, instead of from the amp to the high level input. All better now. Whew!