It is strange that your Sony TV does not have a menu button on the front panel. Most TVs made in the last ten-fifteen years or so should have such a button; both of my sets, my RCA CTC185 in the living room and my Zenith Sentry 2 in the bedroom, have menu buttons that will bring up on-screen menus for brightness, contrast, color, tint, even auto-color.
Sony was an excellent brand of color TV 20-25 years ago; one of my great-aunts had a Sony 12" color portable that lasted at least twenty years, and was replaced by another Sony that worked very well until she went into a nursing home several years later. However, I don't know why Sony left the menu button off your set. You said yours was made in early 1991; hmmm.
I would think a set that recent (built nineteen years ago) would have had a front-panel menu button. How did they expect anyone to adjust color, tint, etc. on a set like this without the remote?
It's a mystery to me. This set was built just about the time universal remotes were becoming popular, as most universals made then (and now, for that matter) were programmed to operate any brand of IR-controlled television, VCR, cable box, etc. made since the '90s. (Every universal remote I have ever used with any late model TV I've owned, including the two sets I have today, has had control codes to activate most functions, including the menus, on most sets.) Perhaps Sony's R&D folks figured that if the user needed access to the video menus via a remote, they could get a universal and gain access to them that way; thus, no need for a front-panel button to activate them. Maybe they thought that the color on these TVs was so stable that viewers would not need access to the color controls at the set (they may have been well hidden on the original remote as well). It is also entirely possible that the R&D people may have designed your Sony without a menu button to prevent children from fiddling with the video and other controls behind their parents' backs, but these are all just wild guesses. Without seeing your set, I couldn't begin to explain the reasoning behind Sony's decision to omit the front-panel menu button.
Sometimes a universal remote will give you access to fewer features on your TV than the original did. The GE remote I use with my RCA CTC185 TV, VCR and DVD player is a perfect example, as it will operate every function of my TV except commercial skip, which I never used much anyway so I don't miss it. This remote also does not have a button for setting favorite channels. On the other hand, I have an All For One universal remote that does have a favorite channel button. I'd use it instead of the GE remote except that the All For One universal does not allow for use of both a VCR and a DVD player--the remote has a function button marked "VCR/DVD", but it can only be programmed for one or the other, not both. (The manual does not have control codes for my late-model Memorex DVD player, either.) There is an AUX function button on this remote, but I have never been able to program this button for either my DVD or VCR, when the DVD/VCR function button has been set for one or the other.
Since VHS is almost a dinosaur in today's HDTV world, I would expect that the newest All For One remotes are being designed with only three function buttons--TV, DVD and AUX. The VCR function will have been omitted. This kind of remote would be perfect for today's twenty-something generation of viewers who grew up (or are growing up) with DVDs, and do not remember (or have a very hazy memory at best of) VHS VCRs. I don't think very many home theater installations have VCRs anyway, as these machines are analog NTSC and probably will not work (or they will operate poorly if they work at all) with today's digital high-definition TVs; a three-function remote will operate these modern systems just fine as well.
For home theaters with a flat-panel HDTV, a DVD and a TiVo or other type of DVR (digital video recorder), to say nothing of a high-power 5.1+-channel sound system, ordinary universal remotes usually cannot be used to operate all devices; these systems require fancy (and expensive as the dickens) home theater remotes such as Logitech's Harmony series to fully unlock their potential. These remotes will operate all functions of fancy home theater systems and often have LED or LCD screens to show the selected functions; some of the very advanced (to say nothing of the most expensive) HT remotes even have touch-screen controls.
There was an article in US News and World Report magazine a few years ago (several years before HD and digital television swept the country) that talked about how technology is all but driving people crazy. One person interviewed for this article said that his fancy new TV had 23 video input modes and a blue million buttons on the remote; more often than not, it took him forever just to change channels. "Half the time I can't even get the stations (I want to watch)," the person said. He went on to say that when he complained to his wife about this, she countered, "Hey, (don't come crying to me). I didn't design the (darn) thing!"