Epson 3880 stoped printing after changing pump and cap assembly

I’ve been trying to bring my 3880 up to speed for its conversion to K7 inks. I had recurrent and inconsistent nozzle checks, and following the advice of others decided to change the caping station. The service manual proved very easy to follow and I thought I had done everything correctly.

However, after starting the printer I noted that it did not print at all despite sounding, and the head moving, as if it was working fine. There is no trace of ink on a test sheet whether the test print is sent from the printer’s control panel or from my Mac.

I also noted that the cap has absolutely no ink on it despite running a cleaning cycle. It looks like ink is just not coming out of head. Of course it was printing fine before the replacement. Any ideas would be much appreciated…