Meridian XL external power warning

Shame on Magellan for not documenting the differences between
versions of its (old) Meridian XL product; the PDF user manual
available on Magellan's website states that the external
power/data cable should only be connected to a 'black'
Meridian XL but 'black' is not explained (is my gray and
black XL 'gray' or 'black') nor is the reason for the warning.

I inspected the PCBs in the unit to determine if the connector
pinouts corresponded to published data on the web and also
'ohmed' power and ground as a precaution and tried to determine
if there is an onboard step-down regulator. Everything seemed
ok, but upon applying +12VDC to the unit, it permanently failed
(had worked on battery). It turns out that what regulation
may exist is limited to about a 5 volt input.

FWIW, not that there are many folks still using the device:
be warned.

Michael