Actually, the problem really seems to be more about the arcade monitor not being recognized properly by the video card. I see that three 75ohm resistors can be used to modify the VGA cable between the J-Pac and video card (and I'm going to try that) to get the secondary display to work in Windows, but I'm wondering what the benefit of that is. If that mod is successful, will CRT EmuDriver be able to detect my monitor's resolutions through the J-Pac, or am I going to have to fidget with each resolution manually? Am I better off bypassing the video component of the the J-Pac?
Hi ncflagg,
Your J-PAC isn't the culprit here, it's the arcade monitor that doesn't load the rgb lines. Even if you attempted a direct connection you'll be facing the same problem. The resistors trigger monitor detection so Windows won't switch off the video output to the arcade monitor. That's all it does, it doesn't have any effect on what resolutions are detected or anything (I don't understand what you mean there), you control all that through VMMaker.
That said, keep in mind this trick comes at a cost: you'll get a considerably dimmer picture, as part of the current will be drained to earth. Instead of 75 ohm resistors, try using higher values, as high as it still works, so you'll loose less brightness.
I've got some 100ohm resistors so I'll start with that. Thanks for the tip!
I haven't heard of this trick to get an arcade monitor recognised, but I can see how it would work. I did an online search but unfortunately found nothing, so would appreciate a link if there is one?
I'd suggest sticking with the 75 ohm termination resistors if possible because this matches the video input impedance expected. If impedance is mismatched then you will get more interference on the video lines in particular any stray capacitive loading and reflection. If that makes the image not bright enough, then try using this simple home-brew RGB amplifier with your 75 ohm resistors:
https://www.retrorgb.com/thsamps.htmlJust follow that design and add your 75R terminators to the RGB inputs. I'd probably also try adding 0.1uF (104) ceramic capacitors in series on the RGB inputs, after the 75R terminators. That "AC couples" the inputs to the homemade amp per industry convention and minimises DC crosstalk between the devices.
I'd also add an extra 22uF capacitor across the 5v and GND terminals, in addition to the ceramic 0.1uF cap that is already there. This will minimise noise on the 5v supply line. The 22uF cap would be electrolytic, so pay attention to polariy (+ to 5v, - to GND)
Then feed from that into your JPAC as normal.