Dreamcast VGA (incorrect) frequency problem

[rakamakafon]

Hello, some time ago I've decided to get into Dreamcast gaming and purchased one. I've successfully tested in out with the supplied composite AV cables and everything worked. Some time later I got around to purchase a VGA cable for it, to get the best picture quality from the console possible. It was one of those cheap all-in-one cables from China, which have both VGA and stereo connectors in one cable. Sure, it probably isn't the best quality out there, but probably should be good enough to check out the VGA output on the console.

Now the problem: it outputs (or at least it's trying to output) a 15.7 khz signal via VGA, instead of the 31 khz signal, which causes the displays to freak out and display an "out of range" service message, without displaying any type of video signal. I've tried both with a game and without one. I've tried a CRT PC monitor and an LCD one. The results are still the same.

So... what may be the problem here? Is it just a shitty VGA cable (I've seen people use such cables with no problems, so maybe it's just defective?) or maybe there's some problem with my console itself? Is there any way to tell, without having another Dreamcast to test against? As far as I've managed to read up, the signal frequency depends on the signal from two particular pins in the connector, so maybe the problem is somewhere there? I would appreciate any help here.

[mvsfan]

It sounds like the cable is actually wired for 15khz 240p RGB instead of VGA. it probably has molded plugs that arent easy to get open, and if it does i would return it. if it doesnt and its easy to open, i would re wire it.

In the console end of the cable pins 6 and 7 are your mode select pins. they both need to be grounded to select VGA and get the cable to output properly. Pin 1 is ground.