Where is the CMOS battery on an HP OfficeJet L7500/7600/7700 series?

(This is #1 in a series of 3 posts. This posting may sound like a
FAQ, but the information I've dug up so far doesn't apply to this
printer family.)

I want to eliminate the "ink cartridge missing or damaged" error from
my HP
all-in-one. I'm exploring three options, and option one is removing
or
isolating the CMOS battery in the printer. Unfortunately, the only
diagram
I could find on the web is for a different model of AIO. Can someone
tell
me (or point me to a website that shows) the location of the CMOS
battery
in an OfficeJet L7500/7600/7700 series AIO?

--
Regards
Ray