tap tempo help needed!

[ninjadave7]

i have 2 dd-5 delays that i'm trying to sync up with one tap tempo switch.  for a long time I used a y-cable and that worked perfectly.  then one day i decided to add a nova delay to the mix thru a parallel jack.  worked fine.  then i took away the nova, reconnected the dd-5's to the y-cable and they won't acknowledge a tap tempo is even connected.  when a connect 1 at a time through a standard cable everythings cherry, and i remade the y-cable using different cable and connectors as a trouble-shooting step, so hopefully that isn't it.

i also tried a stereo jack, with one delay on ring, the other on tip, with 2 wires to the jack from the same lug of the switch.  nothing.

what else could the problem be?

any help would be appreciated!