epson stylus pro 9700 cap problem ?

hi, I have a strange problem, after changing the printhead sudenlly the tape from the printhead dissconected and the printer turn off, I have fixed that. Now I can't start the machine, Power on.... and the epson dont't see the inks. In service mode I have the 1439 error, this is cap error. Service book recomendedto check the ap cap sensor or change the ink system mechanism. I have another epson so i changed both and still the same error.
What could that be ?
please help