I have an old PowerMac G4 (quicksilver) with an Nvidia Geforce 2 MX Twinview monitor. I have bought a Belkin ADC (apple display connector) to DVI adapter and used my DVI to HDMI connector to attach it to HDMI2 on my TV.
However, the TV never shows HDMI2 as available on my Samsung PN50A450.
Using the same cable, but my mini-DVI to DVI cable, I am able to connect my MacBook just fine.
I have manually configured the Mac's settings for the monitor (which it is detecting and using a SAMSUNG color profile) to match the HDMI/DVI input display modes in the manual (resolution, hz, vz, pixel frequencies and refresh rate). i have tried settings for several of the resolutions, etc. None of them trigger HDMI2 to show as active on the TV.
I have attempted to make some changes in the service menu to see if it would help. They didn't (so i changed them back). However, when enabling "PC" mode in the EDID setting (with my TV on and HDMI1 selected, and the computer still connected to HDMI2), while it is "waiting" to test the connections, the PC video momentarily flashes over the HDMI1 connection.