John Gill wrote:
Dave:
I have had some experience with this problem on Dell/Sony GDM-17SE2T
monitors. Behind the flyback, there is a small transformer in location
T403. Mine had the number 998-11 on it.
These transformers develop small cracks in the core that is on the
outside of the windings. This somehow affects the horizontal width.
I had two monitors with narrow widths. Replacing the transformers
with ones from junked chassis fixed the problem.

Just a followup John, after checking the voltages and finding them
spot-on, I pulled T403 and had a good look at it - sure enough a small
crack. When I eased off the tape around it a section of the core
dropped off.

So thank you very, very much for sharing this with me, (and the rest of
us), this would have saved me hours checking resistors, ESR on caps, etc.

I only hope I can get a replacement now, (either the whole thing or
poss. the cores).

Thanks again,
Dave