I am trying to connect my PC with my HDTV. My PC has a GeForce 7300GT video card with VGA, DVI, and TV out. I have an adapter that will allow me to connect to the TV through component cables using the TV out port. The TV can accept a VGA connection, HDMI, and component (among other types). My choices are limited to HDMI and component if I wish to watch 720p content (according to the TV manual).

My problem is that I don't know the values for HorizSync and VertRefresh that go into the xorg.conf file. I have searched my HDTV manual, the internet, and called customer support without success. Normally, I would just tinker around until I found the correct values, but I have read that incorrect values can damage the TV.

Is there a safe way that I can determine the ranges for those parameters? I have read that the TV can broadcast information about itself via the HDMI port. Is there a safe way to use this functionality?

Thanks.

You should give more information like TV Make/Model,Linux Distribution and what video driver you are using.

I highly recommend Search/Google as opposed to my Opinions/Recollections but maybe they will at least point you in the right direction.

If you use a DVI to HDMI (adapter or cable) and you are using the Nvidia proprietary drivers then
Option "UseEdidFreqs" "TRUE"
would specify using the EDID (Extended Display Identification Data) this is the default so unless you specify otherwise the drivers generally take care of you, on my systems (Gentoo/FreeBSD) you can read this (EDID) information in boring detail by going through the /var/log/Xorg.0.log

I have not used component connections personally on a PC so I won't comment on them.

720P is only 1280x720 so i find it odd that the TV does not support it through VGA

Personnally I have 56" RCA rear projection CRT, whose user manual states computer connections are not supported, Useing HDMI the picture is fine for Video/Pictures/10' UI stuff, Text is only passably readable on a normal Desktop setting at 720P, on 1080i settings the screen flicker is just unbearable.
I have yet to damage it by feeding it the wrong signal, I have installed Fedora,Ubuntu,Gentoo and Windows on it, the closest I think I have come to damaging it was by tweaking power strip on windows.

Assuming that you are in the USA (or are running a 60Hz system), then the the field rate is 60Hz and your VertRefresh = 1/60 = 16.7 milliseconds. For a 1280 x 720 progressive display, you have 720 lines in the field (720/2 for interlaced). This means that your HorizSync rate = VertRefresh/360 = 46.3 microseconds (or 23.15 microseconds for progressive).

For a 1920 x 1080i picture, just substitute 540 (interlaced) for the above calculations. You should not go higher than a 60Hz refresh rate, unless your display manual says you can.

NOTE: In video, an interlaced picture = 1 frame every 1/30 second, each frame consists of 2 fields with half of the vertical lines.