Post#19 » Sun Sep 25, 2016 8:55 pm
Hi, I was able to do a little more testing on my setup. I use F-355 Challenge, Test Drive Le-Mans, Shenmue 1 & (Shenmue 2 UK PAL with a boot disc) as my "reference material".
First, I went back to running the Dreamcast using only the TOMEE cable directly to the NEC MULTI-SYNC LCD1970GX monitor (this is an older LCD 4:3 display), and that worked out pretty well. The monitor itself has a small shortcoming where depending on the viewing angle, the very edges might get a little brighter on a black screen. Usually top and bottom, but sometimes the sides too. I noticed this even when it was on, but nothing was sending signal to it. When actually playing the Dreamcast on it, I did not see any of the odd hazy artifacts like on my TV. Everything looked really good.
I then put one of my two random monitor cables in the signal path between the TOMEE and the monitor and did not see any degradation. I then swapped it for the other random monitor cable and again did not see any degradation. In all cases with the monitor, I just saw a little brightness around the perimeter sometimes when the image was dark, and also depending on the viewing angle. I also sometimes saw something like screen door effect if you look closely enough, but I think that is not the monitor, but actually something in the Dreamcasts' actual valid signal, perhaps with how it renders certain shading effects, because I actually noticed that on the TV too, but scaled up since the picture is bigger. I don't think it's actual screen door affect, but it looks kind of like it. But, for the most part, the monitor did just fine being fed the signal from the TOMEE cable alone.
Another thing that I learned about this monitor is that I am able to stretch the image horizontally and get "perfect" aspect ratio. The whole image then has to be shifted over to fit, and it winds up a little off-center, but the whole screen is still full, no black bars. (This monitor actually does not render those black side-bars from the DC to begin with, but the Aspect Ratio is still off to start with.) I had to re-adjust the H-Pos at least once between games (I think going from Shenmue to Shenmue 2, and I may have had to adjust the A/R between 355 and the Shenmue titles, but no big deal, I was able to see them all with full screen, "perfect" A/R, with the image just a bit off-center.
So I would say that this monitor accepts the TOMEE Dreamcast VGA cable with no issues, and does a good job with handling the inherent Dreamcast A/R issues as well.
At that point I'm thinking unless the monitor itself is shielded better or handles the VGA signal somehow better than my TV, there is nothing wrong with my TOMEE cable, or my monitor cables, and perhaps the TV simply does not do well with VGA input.
I did check one thing concerning my perceived lack of ground on pin 5 when testing all 3 of my cables. I tested again and discovered that when the monitor cable is plugged into the TV (or the monitor), those devices will provide a ground path for pin 5. Pins 4,5,6,7,8,10,11 all had path to ground when plugged into the TV or the monitor. I tested from the cable pins to the earth plug on both units just to make sure. The TV had a little more resistance on the R,G,B pins vs the monitor (76ohms vs 75ohms), and on the ground pins as well, where the TV showed about an ohm, the monitor showed about half an ohm. I don't know if that makes a difference, but I doubt it.
I've read that the DC VGA signal is over-driven. I've also read that the signal is under-driven. I've also read that the pixel clock is a weird timing and perhaps that is causing the problem with my TV.
I hooked the TOMEE / monitor cable combo back up to my TV to do some more basic tweaking within the TV menus.
This TV is a real PITA when it comes to settings, and I was able to clarify how some of them differ.
In PC mode through the D-Sub, you have three picture setting modes. Dynamic, Standard, and Movie.
You can change Backlight, Contrast, Brightness for all of them, and Sharpness seems to automatically be set and locked, although it might even automatically change , but you cannot adjust it in any picture setting mode. The sharpness displayed 75 in Dynamic, 50 in Standard, and 20 in Movie, but I swear that they might have changed by themselves at some point, and I will check into that more closely.
The "Screen" menu will let you adjust the aspect ratio via the Course and Fine settings in any mode, as well as H-Pos and V-Pos in any mode. (In 4:3 or 16:9 I could not get the A/R as "perfect" as the 4:3 monitor , although I might go back in there and try some more.)
Ahead's where things change up a little. In Dynamic mode, the "Detailed Settings" menu gets greyed out and you cannot see what is going on in there.
In Standard mode, the Detailed Settings menu is now active, and the Black Adjustment is set to off and not adjustable, the Dynamic Contrast levels are selectable, the Gamma is adjustable, the Colorspace is set to Native and not adjustable, the White Balance is adjustable, Flesh Tone is set to 0 and not adjustable, Edge Enhancement is off and not adjustable.
In Movie mode, the Detailed Settings menu is the same as Standard mode, except that Colorspace is set to Auto and not adjustable.
The final menu across all three modes is the "Picture Options" menu, which is the basically the same across all three modes, and where the Color Tone is selectable (movie mode has a few more choices), size is selectable (3:4 or 16:9), Digital Noise Reduction is auto and not adjustable, DNEI is off and not adjustable, and HDMI Black Level is set to Normal and not adjustable.
So basically if you start out across all modes with the same Backlight, Contrast, Brightness, and Color Tone, it boils down to you won't know what the TV chooses to set within the "Detailed Settings" in Dynamic Mode. Dynamic Mode seems to activate the Dynamic Contrast to some degree, although not as "dynamically" as simply choosing "Standard" mode and running the Dynamic Contrast on "Low", if all other settings are equal.
I ended up with the settings below as a baseline across all modes, and then compared Dynamic mode to Standard mode with different Dynamic Contrast settings (Off, Low, Medium, High). Right now Standard with Low Dynamic Contrast seems to be the best choice for me, and these settings below seem to be close to where I want to be.
Mode : Standard
Backlight : 8
Contrast : 90
Brightness : 44
Sharpness : 50 (not adjustable, value might change automatically, need to observe)
Screen
Course : 35
Fine : 0
HPos all the way right
Detailed Settings
Dynamic Contrast : Low
(all other settings in this submenu left at default or not adjustable)
Picture Options
Color Tone Normal
Size 16:9
(all other settings in this submenu not adjustable)
This gives me a nice picture, despite the weird VGA ghost fog that sometimes pops up. I have no idea what to call it. One way I can see it really well is if I open the Shenmue notebook with a dark background, the screen above and below the notebook pages will have a yellow fog over it.
I'll probably roll the dice and throw a part at it and buy a known-good-quality VGA monitor cable, as I don't know the quality of the ones that I have, but if they were bad I would think that any problems would show up on the monitor as well, unless the monitor is protecting itself from noise better, or if that pixel clock timing has something to do with it, and the monitor can handle it while the TV cannot.
I also ordered a used 3rd-party VGA box, but it is the orange "Madness Games" one and I have heard people say that it is crap as well. Other people say it works fine. I will post up when I get that going next week sometime.
Just as an aside if anyone is wondering, my TV accepts S-Video from my D.C. S-video cable, and it looks just fine with no weird artifacts, although it is 480i.
I also wanted to say that I did one more test by hooking up my laptop back up to the D-Sub on my TV with one of my monitor cables, and ran some you tube videos and stuff like that, and saw no VGA fog or any issues. That was not 640 x 480, rather it was whatever the best choice is, 1920x780 idk. Modern resolution. I did boot the laptop in low res mode 640x480, but it would kick the VGA external output signal back to modern resolution when displayed on the TV.