vga to RGB scart problem

[wilch]

well i finally soldered my cable. i used the simplest method possible as described here: http://forum.arcadecontrols.com/index.php?topic=77370.0 but i linked scart pin 16 to 20 rather than using an external voltage (so i would need to switch to AV mode manually) and i twisted VGA 13 & 14 together then linked to scart 20. i've read that people have had successful with this method. when finished i checked every pin and the casing for continuity. i should also mention i used a regular vga cable & chopped off the end and soldered it to the scart connector.

i'm using a radeon 9250 card and my tv is 21" sony trinitron PAL (50/60hz).

my card has a DVI connected to an LCD as primary display. firstly i installed 15hz using soft-15 and selected my secondary display (the TV which was previously connect via s-video) then set my primary to 640x480 (just in case) then shut down the pc. i connect the rgb scart and rebooted. when windows XP loaded up i tried to enable the greyed out secondary display, but it just remains greyed out without any error or warning... i selected AV with the tv remote but there's no image. i can understand that the lack of voltage to the cable may be a problem for the tv image, but shouldn't the display at least be enabled in windows on the other monitor?

i'm new to this so my understanding is basic. can i even use 2 displays while using soft-15khz?
is one supposed to enable the tv using the usual method (as used by rca, s-video) while using a vga ti scart?

thanks in advance for any advice!

[wilch]

ok, i selected 'force TV detection' in catalyst control centre then rebooted. i can now enable the secondary display and it is no longer greyed out. however, the image on the TV is still black after selecting RGB AV with the remote, so i guess it must be the lack of external voltage...

can anyone explain how this is achieved? i know i can use my PCs 5V supply, but i'm worried about blowing something up! how do i connect the wires to the PCs supply socket? i'll need to keep my PCs side panel open obviously, is this safe?

thanks

[apfelanni]

i used some old 1:1 wired 15 pin monitor cables for mamescart purpose and took the 5v from pin 9 of the vga plug. nowadays those cables are rare and expensive . usually pin 9 ( with some others ) is missing and the rgb wires ofthen are coax.   


http://community.arcadeinfo.de/showthread.php?t=9269 and


http://digilander.libero.it/venturi1975/index.html#A1

[wilch]

i managed to get an image without external molex. i installed soft-15khz to both primary & secondary displays, soldered VGA 5 to Scart 17 for grounding and left the bridge from scart 16 to 20.

i see the image but it isn't right. green is very dominant and is affecting the whole screen.

the image rolled so i enabled composite sync and set horizontal to positive and vertical to negative which fixed it, but whenever i change resolution the screen goes black until i change vertical to positive then back to negative again using the other display. anyone else had this issue?

lastly, am i right is thinking there is no way to filter the flickering using a vga to scart?

[apfelanni]

i askeds a tv -arcade guy for help with the rgb-scart matter ( green-yellow bright picture ) and he said it could only be the sync level output. the rgb level on vga should be 100 % scart compatible . some resistors or potis like its shown in the italo forum diagram would possibly help. yesterday i bought some fitting resistors to solder a cable for a field test and get rid with the problems on some mamescart tvs . this weekend its about 35 deg celcius here , so soldering isnt fun at all , but i ll report as soon i come up with some results.  


rgb flickering ?? maybe ure using interlaced resolutions , like windows 800x600 . ure scart 5o hertz tv cant handle high res in progressive mode but most of the lowres games . if u need crystal clear windows mode u have to get a multisync or highres crt.

[apfelanni]

ok ladies .. i took the time to solder a cable for my problem tv set with the sheme taken from the italo forum. the only diff i made is taken 5 volt + resistor from pin 9 to 16 , instead of a molex pc con and skipped the pin 8 wirering , coz the tv set automaticly switches to av when started . if ure mamescart presents discoloring and or brightness probs u may try it out.