Odd Comp Monitor Behavior: contracts based on activity!

I have an old and very well-used hand-me-down Sony E500 20" Trin. I specified when I started work here that I wanted a 19" Trinitron and this is what they gave me. The graphics folks were no longer able to use it, it had been used so long the contrast and color values aren’t up to par (something about phosphor?). I don’t need perfect color, just sharpness and decent size & resolution, so that’s fine with me.

It does have this one weirdness though: I go to a menu (e.g., the Apple Menu) and the moment I do, the whole image on-screen contracts, like I’d brought up the monitor’s hardware MENU and used the horizontal and vertical SIZE controls to shrink the screen inwards a touch. Or, when I’m in FileMaker, I go into layout mode (whether by going Command-L or picking it from menu doesn’t matter) and for the duration of me being in layout mode the whole image on-screen expands, losing me some edge pixels in the process, again as if I’d tweaked the hardware SIZE menu to expand the screen outwards a notch.

Now, how the heck could & would the monitor know or care what I’m doing in my various applications and OS? It’s a glorified hi-resolution TV tube, that’s all! (I could see it if I had one of those wireless mice and the signal by which the mouse was sending info was somehow affecting the monitor, but it isn’t; and besides…layout mode in FileMaker??)

I have to assume my OS is in some oddball fashion doing something different in its pixel-spewing routine when menus are down or FileMaker is in layout mode, something that this old monitor (but no other monitor) for some reason interpolates at different physical sizes than the pixel-spew coming in when menus are not down or FileMaker is not in layout mode.

But what could that “something” be? On any other display, the same OS and same apps, same physical computer & all, = no weird size-hiccups when I invoke menus and etc.

BTW – the resize-change isn’t instantaneous like a fluctuation. The screen “pulls in” or “puffs out”, the resizing is fluid and continuous over about a half-second when I click on a menu or change modes in FileMaker.

Other – The Sony is hooked to a CardBus video card, the computer is a PowerBook. The problem manifested itself under a different OS (MacOS 9) and a different card (the RoadRocket I used before I got the OS X compatible VillageTronic card). I’m at 1152 x 870 x 32 most of the time. The other screen (the built-in TFT) has its own chunk of desktop / display realestate and that one doesn’t react when I click menus & so on.

My initial impression is that the high voltage transformer (also known as fly-back-transformer) is giving up the ghost. Symptoms are often exhibited when an onscreen image quickly changes from dark to light. Pull down menus (when large enough) against a dark background can cause this instantaneous resize when the fly-back-transformer has been compromised.

Have you heard any crackling noises, smelled burning plastic or wax? If so that would confirm my suspicion. Depending on the monitors value it may or may not be worth repairing.