Converting monochrome video signal to VGA monitor?

Hi, I recently received a Commodore A2024 monitor. This is a 15" monochrome/ grey-scale monitor which has a special converter board inside, that converts the 15kHz video output by an Amiga computer to 31kHz. It also supports a "tiled" mode, whereby Amiga video frames are combined to produce a 1024x800 or 1024x1024 pixel image. Unfortunately the monitor was damaged in transit and the tube is cracked. However the converter board should be usable. I want to make an adaptor to connect the converter board to a standard VGA/multi-sync monitor. Has anyone on the list connected an old workstation (or maybe an Atari ST?) with monochrome output to a modern monitor? Those should be similar. There should be no problem with the horizontal and vertical scan rates. I need to look at the board circuitry, but I'm pretty sure the horizontal and vertical sync signals will be at TTL levels, which is fine for connection to a VGA monitor. The monochrome video signal is output on a phono/RCA socket. Inside the monitor, a coaxial cable goes from that to the PCB at the end of the tube. I need to determine the video signal level. Apparently VGA uses 0.7V p-p, so I might need to add a resistor in-line to reduce the voltage if it's any higher. Unfortunately I don't have access to an oscilloscope. Could I just arrange for a full-screen white image to be shown, measure the voltage using a normal DC multimeter, and multiply up the value shown to account for the proportion of each scanline corresponding to sync/flyback? Once that issue is solved, I should be able to connect the video signal to the green signal pin of a VGA monitor and get a green picture. In order to get a grey-scale picture, can I simply connect the video signal via resistors to each of the R, G and B pins on the monitor connector? If so, what resistor values would be needed? If not, I guess I could use or build a 1-to-3 splitter/amplifier circuit, then connect the 3 outputs of that to the R, G and B lines. -- M