Hello,
The 5000 does not have four pin speaker link or power link, the best way to connect them is via RCA.This is much better than speaker level anyway. Also the pre amp in the 5000 was better than the later 5500,6500,7000 which are more basic.
Be sure to set the pentas to max sensitivity when connecting via RCA, also note that either speaker level or RCA you will not get display from the pentas with the 5000, that came from the 5500 onwards.
Erik