Monitor trouble! Input not supported. PRAM and NVRAM reset with no results!

Hi there.

I have a problem which I'm hoping to find a solution.

I recently purchased from ebay a g4 tower.
I connected an (known working) LCD monitor to said g4 tower (spec unknown).

G4 chimes when turned on and I get a grey screen with apple logo and the circular dashing icon telling me to wait. I wait. Then the screen flicks to black and I get input not supported.

Having spent numerous hours google-ing and searching forums I decided to post for help as all the topics i've read about talk about doing a PRAM and NVRAM reset.

I have done a PRAM reset and heard the extra chimes several times (several times of hearing several (upto 5) chimes). So PRAM reset check!

I have done a NVRAM reset and done the "command + Option + O + F" reset nvram splurb and rebooted (Which the monitor displayed so nicely). So NVRAM reset check!

Same result, grey "startup" screen with circular dashing icon flicking to input not supported.

Is there an easy solution to this problem?

Would putting in a different graphics card temporarly force a lower res / refresh rate so it would be supported?

Can I type in a different string of commands following the "command + option + O + F" to force the os to use a lower screen res / refresh rate?

Help warmly appreciated.

Josh

It'd be good to know the size of the LCD monitor and the specs of the G4 tower's video card .... then we could determine the compatability between them. This could possibly be the main issue.

I have no idea about the mac as I can't get a GUI to tell me so it's kinda mute. I know the monitor is supported by old macs as it's been given to me via a friend with old g4's. So i know it's not a simple compatability issue.

Do you think a reinstall of the os could help? I don't have the current install disks for this mac so I may be up/down grading. Do you think this may help??