I've been curious what it would take to convert a B&W Mac Classic to grayscale and VGA with the ORIGINAL CRT and analog board.
I haven't really been able to find many details on how the Color Classic VGA mod works, it seems all that's required to support a 31.5kHz horizontal scanning frequency is just to boost horizontal deflection voltage from 60V to 68V, then tweak some trimpots? Is that all it takes? If so, couldn't in theory a similar mod be performed on the B&W Macs as well?
The B&W analog board only supports a TTL video input and I admit I don't really understand how the video amp works, but being that the CRT itself is analog and so is most of the circuitry in the video amp circuits, I would think it should be possible to modify it to accept an analog VGA signal for a rather low cost. The Classic doesn't have the NAND inverter like the 128k/512k/Plus, so I tried feeding it variable voltage. It appears as though the screen will display grayscales between 1-2V, although it's difficult to tell since I don't have a proper picture.
Thoughts?
I haven't really been able to find many details on how the Color Classic VGA mod works, it seems all that's required to support a 31.5kHz horizontal scanning frequency is just to boost horizontal deflection voltage from 60V to 68V, then tweak some trimpots? Is that all it takes? If so, couldn't in theory a similar mod be performed on the B&W Macs as well?
The B&W analog board only supports a TTL video input and I admit I don't really understand how the video amp works, but being that the CRT itself is analog and so is most of the circuitry in the video amp circuits, I would think it should be possible to modify it to accept an analog VGA signal for a rather low cost. The Classic doesn't have the NAND inverter like the 128k/512k/Plus, so I tried feeding it variable voltage. It appears as though the screen will display grayscales between 1-2V, although it's difficult to tell since I don't have a proper picture.
Thoughts?