Digital BW, The Print

Just picked up an Epson 1400 and a set of UT-14 carts to mess around with.
First I installed the six Epson color carts to make sure everything worked ok with the
printer, which it did. So I popped in the UT-14 carts...and not a spec of ink came out of 
them.
After many cleaning cycles and prints of purge files, a trace amount of ink appeared.
Switched back to the Epson color carts and everything worked great again. Switched
back to the UT-14 carts and nothing.
Anyone have any problems with these prefilled carts for a 1400? 
Or am I missing something simple, like I need to remove one of the rubber plugs on the
cart?
Stumped.

Jim Rohan