King DME's

Just wondering if anyone has removed a King DME from their aircraft.
Ours was removed to satisfy Canadian regs when it was imported from
the US. The AME told us just to replace it after certification. I
noticed a locking cam at the front centre of the DME. Trouble is when
I insert it into the tray it does not seem to go into the tray the
entire way. I don't want to force it be I'm afraid I might damage the
terminal plug in the rear. If anyone has removed and replaced a unit
before your comments would be appreciated.

Thanx Jurgen