Inoperative ZDE(s) after CES Software Upgrade to Version 7
It has been noted on some aircraft that after upgrading the CES to V.7 the CES Diagnostics page showed ZDE 3 (or 4) inoperative and the Diagnostic Details page showed a failure of the MDSB BUS controller. The switch panels associated with the ZDE did not respond.
This is usually not due to a faulty ZDE.
Perform at least 8 boots of the system and you can expect that after the 3rd or 4th boot you have a ZDE 3 or 4 inop with a MDSB bus controller fault. You may have to do another 8 boots.
One more tip - if replacing a ZDE on a Version 7 aircraft, boot the aircraft on only one MCE cabinet (MCE 2 preferred because you will have the Galley TSE. i.e. pull breaker for MCE 1). A new ZDE seems to accept the software on the first boot up if only one MCE is live.
