Originally Posted by Mark_Likes_Games
1- Is the only way to leave the service menu to turn off the TV?
Yes, at least that I'm aware of.
2- If I make some changes to parameters and NEVER WRITE them to memory, what does the command  then [enter] do?
I don't know, nor do I know why you would press  then enter, but then again it's been quite some time since I've worked in the Sony's SM ...
I've only used the 1+3, 2+5 and 3+6 number keys when working in SM. 7~9 keys were "off limits" for my fingers
.... From KenTech's "02-navigating Service mode" post :
Originally Posted by KenTech
CAUTION: AVOID keys 7 and 9, as they are part of a key-sequence that can reset all of the deflection or image-decoding settings back to a "factory-newborn" state. If you think you've hit any key by accident, STOP. In a few seconds it will revert back to SERVICE mode, as you'll see at the right side of the screen. All dangerous key-sequences are combinations of *three* keys, by the way.
Does this reset even things I didn't adjust to some other default values?
The key combination that does that is the one Ken Mentions as quoted above. Don't do it
. Going from others who did make that mistake(after many warnings here cautioning them NOT to do it), The "other default values" are not the defaults as they were "adjusted" at the factory, instead they are likely some set of useless(except perhaps for those at the factory starting on every set with the "same" set of values to start with) defaults present BEFORE any factory adjustments were made.
Also in the post "02 - Navigating Service Menu" it says press - Enter to reset settings but this resulted in a message something like "feature not available" (I don't quite remember).
FWIW, I think I may have tried that once+ I think it may worked on my XBR960, but other than testing it, I never used it as I preferred, basically, not giving myself that "option", although on occasion for testing some things out(w/o writing any values) I did use the power cycling option to clear my "new" values(often on those occasions I wanted to power back up outside of SM anyway) ..... And instead, was sure to be careful enough to log everything as necessary and it was easy enough to change values back if I had already written them+ended up wanting to use something different or the "factory adjusted" default values ...
Hope some of that helps ....
Sorry if this seems basic.
Not at all.