arfink wrote:I've been pointed this way by some folks who were unsuccessful in trying to help me RGB mod my monitor. Thanks in advance for the help! I'm currently trying to convert an old "prosumer" monitor for arcade use. It's the Proton 602M, and in its day it was a very high-end monitor. I got this one from the original owner, who barely used it since the 1980s, and the tube and chassis are still in absolutely fantastic shape for their age. It apparently has been serviced for a recap at least once in its life, so it was very well cared for. This monitor also had a special power supply with drive and deflection circuits built separated from eachother, with a crazy-weirdo split flyback like nothing I've seen before. As you can see, the convergence and geometry are still pristine. Hence, why I'd love to build it into an arcade machine.
Note that this monitor has no OSD, no closed captioning, no PIP, nothing of that sort. Originally it came with composite input and TTL RGB input, and that's it. Much of the onboard logic is done with discrete transistors, but there are a handful of ICs whose datasheets I cannot seem to find because of age.
(the image below was generated with composite input)
Unfortunately I'm having issues with modding it for RGB, and I'm hoping some folks here could help or at least point me in the right direction. When I have my signals hooked up, it looks like this:
Right now I have a Neo Geo MV1C mobo hooked up to it, and the RGB signals are attenuated with 240 ohm resistors, and the sync is attenuated with a 1k resistor. I am currently inputting sync through the composite input jack, and RGB are connected to some convenient test points labeled TP-54R, G, and B. You can see them on these circuit diagrams.
Annotated Circuit Diagram.Red and Green highlights indicate RGB input test points, yellow indicates various sync injection points I tried. Note that only sync injection point 1, the composite input, had any effect at all. All other injection points seemed to produce no image at all.
Block Diagram
More circuit diagrams for daughter boards
Additional Photos: https://photos.app.goo.gl/cF9RUwfsmknwD5LK9
I am not an expert at all, but are you sure you are not going into the RGB lines that go straight to the neck and skipping any benefits the IC would be giving you? Again, I could totally be wrong. If you are, there was someone in the thread that did that but it was a very different circuit that they had to make.