Hello guys ! Im new here on forum and i need help with some questions to do the vga mod! Its really needed the 2 resistors of 15o ohms 4.7 and the 3 capacitors of 220 uf ? I see people doing with only the 2 150ohms resistors or even with none , directly to the vga conector . Its possible use a rgb scart cable dreamcast conector and then conect the cables to the vga female conector to avoid open the console and soldering in the board ? I think the rgb cable have all the pins needed ( v-sync,h-sync, rgb , 5v etc ) . Well i see the monkeys guide continues wrong ,since we need to put the v-sync and h-sync cables from the dreamcast conector passing in the two 150 ohms resistors first ,right ? Sorry the bad english ( im from portugal) i hope you guys can help me , since i see here very people with experience in this type of things . Regards :friendly_wink:
I've made a lot of internal vga mods with the mmonkey tutorial and all of them worked fine. Also, if you have a cable with all the needed pins, you can make an external vga box with that.
The Dreamcast has 2 modes using the RGB lines. 15K RGB and 31K VGA. The RGB mode has a dedicated C-SYNC line and VGA has the dedicated H and V SYNC lines. Both use the same RGB out lines. RGB is selected by grounding pin 7. VGA by grounding pins 6 and 7. RGB is on pins 16, 15, 14 in that order. H and V SYNC on 9 and 8 in order. C SYNC on pin 10. GND on pin 1. I'm not sure on the resistors and such needed ATM. Picture of pins if it helps:
Right. Most games can use VGA. For peak compatibility, you'd have to wire in both a VGA and scart connector with mode switch. Some titles like Skies of Arcadia only enabled 15khz (PAL disk) or 31khz (NTSC disk).
Thanks for the responses ! So and i can conect the cables without capacitors or resistors ? Its made diference for the image quality ? And the wires i can use rj45 lan cables in the case of using a internal vga mod? regards... Well i do the internal mode using the scematics of Moonkeys guide swapping the 2 cables from the dreamcast conector of ( H-sync and V-sync ) to pass 1º in the two 150 ohms resistors and its works amazing !!!!! I use rj45 cables for all and a cable more strong to 5v and ground and sound ,and seeing the videos on the net of some of 3º party vga boxes i think the internal vga mod have much more crisp and brillant image ! The only thing im concerned ( not very important ) its im only can switch from rgb to vga mod since i turn of the dreamcast , so i can play with composhit cable in a tv games not compatible with vga , but to do the trick in my crt monitor its not possible, its normal the two modes only change when we disconect the power of the dreamcast ? Im doing something wrong? I use a switch like this but without the two unused pins marked in yellow ! But this pins dont have any use so ... Its not really +possible swap from the modes with the console power on and switch from rgb for vga after the first loading screen of the not compatible vga games ?
If you connect video pins 6 and 7 together (even if not grounded) it can cause issues with rgb cables. By the way, if you don't care about rgb cables, soldering those two pins to the shield of the VGA plug makes the mods switchless. Using a bus chip that switches when a pin is low/high could make it both switchless and RGB friendly.
IM sorry but im misunderstood ( srry the english ) the rgb mode works well if i put in a tv ! I put the rgb and vga cable in the switch like in the image but in the dreamcast conector they are separate since if i put it together i cannot use rgb mode anymore in old tvs ! But my doubt is if its possible switch from rbg -vga modes with the console turn on ! Its because i use a switch with the missing two unused pins ? or its not possible switch the modes with console power on ? Because i want to play not compatible vga games with vga quality in my crt monitor . Regards...
OH god! Im really beeñ misunderstood! In no the monitor dont acept the rgb mode but im seeing people in the youtube doing swap tricks ! IMagine i put a game like skies of arcadia or others in vga mode, they put me a warning message saying the game dont acept bla bla bla . What i want to do is , put the switch in rgb mode ,then turn on the dreamcast , my monitor gonna says no signal etc ! but the game are entering and when i listen the gd-rom loading from the sega logo to the game , turn the switch to vga again and the monitor turns on and tricks the game to acept the 31khz mode ! The problem is i cannot change to vga again since i dont turn off the console and this way i cannot trick the game ! Do you guys understand now ?
I think I got it. You want to trick non-vga games into booting in VGA using the "switch trick". Afaik switching to VGA right after the end of the bootup animation should works. Maybe it has to be connected to a TV to work, I never tried without. Good Luck! FG
My VGA box has a switch to enable 15khz VGA for compatibility issues. You can boot with 15khz mode first then turn on the switch for 31khz.
Thanks to all for the responses ! And im sorry to not explain all correctly ( my english is average ) Well its all doing well now , the only thing i have to do is ... put the switch in rgb mode and turn the console on , and after the game boots to sega logo put the switch in vga again ! My monitor continues saying ( no sync ) but after 10 seconds or more its turns on with the game loaded !!! Because its take so many time to do this i thinking im doing something wrong with the vga mod and the switch but i have only to have a little patience ,looolll! Thanks and regards to all of you guys
For now its not needed , but like i said in the pm maybe i buy one of your box with the scanlines and vga mod ! Do you have a sd card too ?
