One more for tonight - flickering on PAL Dreamcast in 60hz

[Mangaman]

Sorry for bombarding the boards, I'm on a roll and remembered a problem I've had with my PAL Dreamcast's video output someone else might have encountered and found a fix for!

I have a launch-day PAL Dreamcast, so maybe it was a problem with early machines (I've seen it on my brother-in-law's PAL DC as well, and I'm pretty sure his is a launch machine, even though he bought it second-hand, but a friend of mine had a later-model PAL DC and had no problem). Anywho, in 50hz there isn't a problem, but it you set a game to 60hz (or if it boots in 60hz by default like a lot of import games), there is a constant flickering at the very top of the screen. The picture doesn't roll or anything, it just flickers in different colours - I remember that if it's a white screen, it flickers dark blue, grey and black in no discernable pattern; definitely looks like something's messing with the signal. It goes the entire horizontal length of the screen and is only a few cm long if measured vertically, but its annoying as hell. I've tried it in s-video and composite and it happens regardless. In VGA there isn't a problem though.

The only thing I haven't done is bridge R422 which changes the colour signal from PAL to NTSC (does nothing to the refresh rate), so I'm thinking it might be worth a shot to see if that fixes it up when I push it to 60hz.

As an aside, my display is fine with all the machines I've thrown at it (NTSC 3.something/4.43, PAL, PAL60, etc), so I know it's only a Dreamcast problem. I've also tried it on a couple of displays and the problem has occured on each one. The only time there hasn't been a problem is when I hook it up via VGA - no problems there.

Anywho, any thoughts on this? Again, sorry for getting carried away with posting tonight, hopefully I'm not being too much of a pain!

-Mangaman-

[Link83]

Not quite the same problem but when I use any system in 60hz on my Toshiba CRT I get 'flickering' in the corners of the screen. I assume its down to the TV as my old cheapo supermarket one didnt used to do it.

I actually made a thread about it years ago on another forum, here:-
http://ntsc-uk.domino.org/showthread.php?t=54966&highlight=60hz+flickering
Read the reply I got from Toshiba!

As you say the flickering isnt there in 50hz. My flickering doesn't change colour though, and I have just learnt to live with it 

[Mangaman]

Thanks for the reply Link83 - I love that response from Toshiba, what idiots!!!!

If I was getting flickering across all my 60hz sources I'd know it was the TV, but I've hooked up plenty of devices in composite, s-video and component running in vanilla PAL, PAL60 and NTSC, and I've never had a problem with any of them, it's only the DC. I don't think it could be the cables as I get the problem with my official DC cables as well as my Hais VGA box (used for S-Video), but like I said, when running it in VGA (which I'm pretty sure uses a 60hz refresh rate by default), there's no problem. By extension, I'd imagine RGB would be fine as well, but I don't know much about SCART and RGB signals, except that they're apparently very nice

So, I'm still stumped I brought up this topic a few years back on another message board, but didn't have any luck. Given the resident gurus here, I figure someone may have some ideas

-Mangaman-

[Link83]

By extension, I'd imagine RGB would be fine as well, but I don't know much about SCART and RGB signals, except that they're apparently very nice

I was actually running the PAL Dreamcast through an Official RGB Scart cable (and it is very nice  ) and still had the flickering, so it may not solve the problem 

[Mangaman]

Bummer, sounds like it's being a real pain in the rear with your setup I might try bridging R422 over the weekend if I get time (well, I'll install a switch to jump between the two modes) and see how I go. Will post up here if I've had any success so if anyone else out there is in a similar position, hopefully it'll help!

In the meantime, if anyone has any other bits of knowledge to impart, please feel free to do so

-Mangaman-