Zenith SD2743H TV Service menu?
 

Hi all,
I have a Zenith SD2743H TV that forgets it's programming when unplugged.
I have read in the newsgroups about a "Service Menu" and some ways of
accessing it, but this model does not have a "Menu" button. How do I get to
the service menu?
Also there are three buttons accessible through little holes - what do they
do?
Thanks,
Harvey