Service menu in flat-panel TVs; "high voltage" on flat panels?

[Jeffhs]

Are there on-screen service menus in today's flat-panel televisions, accessed by keystrokes on the remote? I'm not interested in altering any service-control settings on mine (rebadged Sylvania 19" FP); I am just curious, after reading the posts dealing with the OS service menus (and the methods used to access them) on 1990s-era CRT sets. .... Which reminds me. Is there an OS service menu on the Zenith Sentry 2s? Again, I am curious since I have such a set, which does not seem to have variable adjustments for height, width, centering, et al.

Again, I am definitely not interested in changing (and will not change) any service control settings on either my FP set or my Sentry 2; I am simply curious as to whether the sets have on-screen menus for service adjustments since, as I mentioned, the Zenith does not seem to have variable potentiometer controls for height, width, linearity, etc. (unless they are hidden behind the set's back cover, which I have not removed in the 16 years I've had the set); I do not see any such controls on the FP either. Are FP TVs so stable that they do not need manual adjustments for picture size, height, width, etc., even to compensate for component aging, or do the components in FPs not age as quickly as those in CRT sets, due to lower voltages in the former? For that matter, are there any really high voltages (in the kV range) anywhere in today's FP sets? I would think not, since LCD displays typically do not need thousands of volts to operate properly.


Thanks in advance.