OCM 50Hz - 60Hz

Door luppie

Paladin (864)

afbeelding van luppie

23-06-2008, 18:50

Hi, this weekend I bought an OCM, but have a strange thing with it.
Deafult the video output is in 60Hz, when connected to my Dell 2407FPW flatpanel it has a perfect picture.

But when I'm starting some Demodisks that sets the frequentie to 50Hz, my flatpanel goes black.
I think it's strange that my screen is able to show a 60Hz NTSC picture and not a 50Hz PAL picture (living in the Netherlands and we normaly use PAL)

Is this an OCM issue or a flatpanel issue (or a user issue LOL! )

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Van Grauw

Ascended (10580)

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23-06-2008, 23:31

I think most VGA monitors require minimum 60Hz input frequency, and if you change to 50Hz the monitor doesn’t understand the signal. Think the solution is to use an RGB cable instead, or try a different monitor/tv. Or see if the demo has a 60Hz option (holding select while loading or something? worked for some demos, at least).

Van Edwin

Paragon (1182)

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23-06-2008, 23:38

IIRC, there's a problem with the frame size in 50 Hz VGA mode. There was some discussion about it in the improvement thread.

Van DamageX

Master (217)

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24-06-2008, 03:12

I'm guessing OCM's VGA output just doesn't work right at 50hz. I have a VGA monitor that works at 50hz on my Amiga, but not with the OCM.

Van luppie

Paladin (864)

afbeelding van luppie

24-06-2008, 10:56

OK tried somethings. If I use loadrom I have the possibility to switch between PAL & NTSC so I'm using that to test what works and what does'nt work.

Te problem that i'm having is showing when I use the svhs connector to my monitor. If I switch the DIP switches to use VGA instead and connect the OCM with a VGA cable to my monitor it works both 50Hz & 60Hz but the quality of the VGA is poor, the svhs is giving me a much bether picture.

So now I know that both 50Hz and 60Hz is working on my display, but only when it's connected to my VGA, why does'nt it work on svhs ??

Van SaebaMSX

Hero (533)

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24-06-2008, 12:08

Have you checked the firmware versions by HRA? As Edwin said it was discussed before, but I don't know if it was fixed.

50/60Hz works for me too through VGA Output with a VGA->RGB cable, but I don't know if it is because of the version. I've never tested the S-Video connection.

Van luppie

Paladin (864)

afbeelding van luppie

24-06-2008, 12:17

RGB is not an option for me, cause my monitor doesnt have a RGB connector.

I use the firmware 2.2b from KdL, the only thing I can find is that : Forced all VGA modes at 60Hz
So I think that if I use VGA and swap the refresh rate to 50Hz the OCM will still force it to use 60Hz and it wont do that on svhs.

Van Ge.Nie.

Rookie (30)

afbeelding van Ge.Nie.

26-03-2009, 17:20

S-Video works fine! Even sharper vieuw than regular SVHS (=scart?). My problem is that I don't have colour. But that is most likely due to the DIP-switches.