Forget what you have read about this monitor on the net. It uses a resolution of 1280 x 960, NOT 1280 x 1024.
Since it uses syncronization on the green cable instead of on 2 separate cables, an adapter is needed. I use the 0215-PCS PC Sync Adapter from Griffin Technology. It costs $30, and gives an excellent signal. (Not anymore. They are discontinued, BUT you may get them from me, since I still have some left, including cables.)
Spec: A1097C is a monosync monitor from Hewlett packard. It is not adjustable, but is made for one single mode only, which is 1280 x 960, at 72 Hz, a perfect 4:3 monitor. Sync on green.
This is what it looks like. There are 3 BNC connectors on the back, so synchronization has to be on the green wire. There are rumours that there are variants with 5 connectors. (According to Dusan Jankovic it is possible to adjust this monitor for lots of other resolutions by using a screwdriver on the hidden controls, marked with yellow on the picture. There are markings on the metal inside.)
# Modefile written by !MakeModes version 0.26 (14th December 1994)
# 1280 x 960 (72Hz)
mode_name:1280 x 960 (72)
If you managed this on another card, please email me.