Chosen Solution
Extremely extremely dim. So much so that when I powered it at a local Mac repair store he said you were saying it is dim but it appears it is not booting. I had to show him in extremely dark room that every thing is working except that the screen is very dim. Tried all the brightness settings, resetting PRAM settings, changing external display but still no solution yet .
S B sounds to me like a bad graphics card. Replace it and re-evaluate
Have you tried another computer with the display, also you may need to replace the GPU if that fails.
This is a very odd duck! My first thought was either the display or the GPU board you have in the system was bad. But I would have expected a messed up image as well if the scan was off. Given the age of the system have you replaced the PRAM battery? Let’s start with that. Do you have a DVM to check the power supplies voltage.
