Main > Monitor/Video Forum
How to use SCART for our hobby
Zebidee:
Try the molex power first, especially 5v+100ohm resistor => 2v at SCART 16. Then see if that works.
wilch:
i managed to get an image without molex power, but i'm having other problems. im writing about this on 3 different threads now so i'll link to this one: http://forum.arcadecontrols.com/index.php?topic=66402.1880
check that out if you'r interested. any help is appreciated, thank you
wilch:
i'm starting fresh on a new vga-rgb scart. my new vga cable arrived and it seems much better quality than the last. pin 9 is present and the RGB wires each have their own shielding.
can i use vga pin 9 instead of bridging scart 16 - 20? does a radeon 9250 pin 9 give out 5v?
UPDATE: on closer inspection i've realised this cable is designed differently. vga grounding pins 6,7,8,10 all share a common link with each other and the shielding/casing. there is a small sheet of metal connecting the pins, but there are no wires. the shielded RGB wires have an additional wire wrapped around them within the shielding which i may be able to solder to the corresponding scart RGB grounding pins. would it be ok having all ground pins on both vga and scart side being linked. there is no wire coming from vga pin 5 at all
Zebidee:
--- Quote from: wilch on July 30, 2010, 09:09:12 am ---i'm starting fresh on a new vga-rgb scart. my new vga cable arrived and it seems much better quality than the last. pin 9 is present and the RGB wires each have their own shielding.
--- End quote ---
Experience has taught me to always check the VGA cables with a multimeter set to 'ohms' before starting the job. Anything more that a few ohms resistance, especially on the sync, can cause noticeable problems. This can sometimes even be a problem with purchased VGA extension cables. I've tracked issues to this before, after much frustration and head-scratching. (caveat: some, e.g. Sailorsat, actually seem to suggest putting resistors on the sync, but I don't think that would do any good in most cases).
--- Quote ---can i use vga pin 9 instead of bridging scart 16 - 20? does a radeon 9250 pin 9 give out 5v?
--- End quote ---
Yes, but you also need the 100ohm resistor
--- Quote ---UPDATE: on closer inspection i've realised this cable is designed differently. vga grounding pins 6,7,8,10 all share a common link with each other and the shielding/casing. there is a small sheet of metal connecting the pins, but there are no wires. the shielded RGB wires have an additional wire wrapped around them within the shielding which i may be able to solder to the corresponding scart RGB grounding pins. would it be ok having all ground pins on both vga and scart side being linked. there is no wire coming from vga pin 5 at all
--- End quote ---
Grounds are usually common at both the TV-SCART input and video card output ends anyway. Check it out with your multimeter on diode-test, if you are curious.
wilch:
thanks for the reply Zebidee. im familiar with testing continuity but not the ohms setting. what would i be looking for when testing the cable?
i built the cable best i could with what was there.
VGA SCART NAME
1 ---- 15 Red Signal
2 ---- 11 Green Signal
3 ---- 7 Blue Signal
13+14 ---20 Sync Signal (neg. H-Sync + neg. V-Sync = neg.
the vga pins 6,7,8 and 10 were all linked to the shielding/casing so i bridged scart pins 17, 13, 9 and 5 to the scart casing which is linked to the vga casing. so all ground pins vga & scart are common
well i tried it out and got a black screen. if i set vertical sync to + then i get a rolling image... i think maybe i should double check all links for continuity and reinstall drivers... any other suggestions?