D800 does not restart after CR unit replacement

[EDUT]

Hi all.

After replacing CR unit on Surelab D800, the printer does not restart.
When pressing start button, the blue led flashes once, I can hear sort of 'clic' ; and that repeats every 2 secondes endlesssly. No start.
I checked connectors, sensors, ...everything seems ok
Did I miss to check something.  Any idea ?
Thxs 

[EDUT]

Argh... Sorry guys... found connector not fully inserted .... apologies...